# Need help setting up a large lathe (air interlock)



## Entropy455 (Jul 24, 2018)

I just purchased a large hobby lathe. It’s an Axelson-Clearing Model 2516, manufactured in 1960, with a 40-horsepower drive motor, about 18 feet between centers, weighing roughly 25,000 pounds (weight estimated by the crane operator). I intend to power the machine with (qty 2) 40 horsepower rotary phase converters, wired in parallel. My problem is that I’ve been unsuccessful in locating any literature on this lathe (e.g. wiring schematic, parts list, operator’s guide, lubrication & maintenance requirements, etc). I am particularly interested in the air interlock – where the machine will not energize without being fed a source of compressed air. Why?


Any help would be greatly appreciated!


----------



## TonyM (Jul 25, 2018)

Was it originally fitted with a pneumatic chuck. Normally these had a safety interlock to prevent rotation if air pressure drops below a set level.


----------



## SmithDoor (Jul 25, 2018)

Entropy455 said:


> I just purchased a large hobby lathe. It’s an Axelson-Clearing Model 2516, manufactured in 1960, with a 40-horsepower drive motor, about 18 feet between centers, weighing roughly 25,000 pounds (weight estimated by the crane operator). I intend to power the machine with (qty 2) 40 horsepower rotary phase converters, wired in parallel. My problem is that I’ve been unsuccessful in locating any literature on this lathe (e.g. wiring schematic, parts list, operator’s guide, lubrication & maintenance requirements, etc). I am particularly interested in the air interlock – where the machine will not energize without being fed a source of compressed air. Why?
> 
> 
> Any help would be greatly appreciated!


Axelson is very good lathe 
In 50s and 60s the ever one when horse  wild. I found even on large lathe the most horse was 5 up. After spending $5,000.00 in parts1983 (Today that is over $12,000.00) to upgrade my my power to 480 volts and 400 amps to run one lathe. This disappointing to find the best I could 5 horse on a single cutter
After that I use10 horse power an save money. 

After spending look at how much power can I use on a tool.
I found that tools they made from 1930 to 1940s was most horsepower that any could use on machine tools 

Dave


----------



## SmithDoor (Jul 25, 2018)

They same for turn on and off machine tools.  I do not know how many ways to could  turn on and off a motor in 60s and 70s.

Dave


----------



## Wizard69 (Jul 25, 2018)

you have one very nice lathe there.  





Entropy455 said:


> I just purchased a large hobby lathe. It’s an Axelson-Clearing Model 2516, manufactured in 1960, with a 40-horsepower drive motor, about 18 feet between centers, weighing roughly 25,000 pounds (weight estimated by the crane operator). I intend to power the machine with (qty 2) 40 horsepower rotary phase converters, wired in parallel.


Im not sure id go that route.   First will you ever actually use that 40 horse power?    It is not for me to say but it is something to think about.   Also consider how much of that HP is going to overcome friction.   I just have a hard time imagining a cut using 40 HP of energy on a geared lathe.   

Id seriously consider the possibility of a VFD and a smaller motor.  You would need to research the latest drives to see if a suitable unit exists for single phase service.   Then you have to balance the costs against two 40 HP motors acting as rotary phase converters.    You would also have to consider if your electrical service can even handle the start up of such a phase converter.   If you need to implement a soft start solution a VFD might be cheaper.   This especially if you can get by with a smaller motor.   


> My problem is that I’ve been unsuccessful in locating any literature on this lathe (e.g. wiring schematic, parts list, operator’s guide, lubrication & maintenance requirements, etc). I am particularly interested in the air interlock – where the machine will not energize without being fed a source of compressed air. Why?


Interlocks are very common in machinery.   Until you have a manual in hand your best bet is to trace out the entire pneumatics system.   That being said i wouldn't be surprised to find a clutch brake unit on the machine.  Lesser possibilities include pneumatic actuated shifting forks, control valves for coolant and lubrication.   On a machine that old there are other possibilities for the air.  

In any event the machine wouldn't operate without air to the clutch brake.   This would be the primary reason for an interlock.  


> Any help would be greatly appreciated!



Check out the lathes web site in the UK to see if they have info.


----------



## Entropy455 (Jul 26, 2018)

It will take 80 horsepower of rotary phase converter to start a heavy 40 horsepower gearhead lathe (rule of thumb). Once the lathe is running, I could theoretically turn off one of the 40 horsepower converters, and it will run just fine up to about 30 horsepower of spindle power, on the single converter. The problem with staring large gearhead lathes is the very high surge-power required during startup. If the converter is too small it will stall out, and trip the main breaker. I have 350 kcmil feeder wires feeding the shop (240 vac single-phase), being feed via 37.5 kVA transformer. The transformer is large enough to run an honest 40 horsepower 3-phase motor via rotary phase converter - in steady-state. The question is how badly the lights will dim with 80 horsepower of converter, staring a 40 horsepower lathe (which could draw upwards of 1400 amperes during startup). Worst case I'll request the power company install a 50 kVA transformer - which they'll happily charge me for. . . . I figure the idle current for two 40 horsepower converters will cost about 68 cents per hour (assuming 12 cents per kWhr), which is not a big deal for a machine that will only see occasional use.


----------



## Entropy455 (Jul 26, 2018)

Here’s pictures of a 10-horsepower converter I built to power my smaller machines. Works like a champ.


----------



## Wizard69 (Aug 9, 2018)

Did you ever finalize this?

While ive seen nothing advertised recently id shop around for a solid state VFD to run this size motor.  Unless you find used your rotary converter motors will cost a fine penny.  

There is no doubt such a VFD (if it even exist) would be expensive but you would gain advantages such as soft start and variable speed.  You might even save on the cost of a new service transformer.

A little edit:  

Im wondering if you chased down the reason for an air interlock.   If it is for a brake clutch you might have more manageable motor start up currents.  Also other soft start solutions might be viable. 

There are likely a dozen ways to get this lathe running.  It is just a matter of figuring out the correct path for your usage.


----------



## Entropy455 (Aug 9, 2018)

Not resolved (yet).

The chuck seems to be a traditional D-type locking mechanism (non-air). My best guess is that air is somehow used within the clutch/gearbox/transmission.

Right now all of my effort is on the phase converters. It is going to cost me about 2500 bucks to build a pair of 40 hp converters - provided I use SSRs in lieu of contactors. I'll take pictures of the converter construction. . . .


----------



## dkwflight (Aug 10, 2018)

Some hobby lathe.
Maybe you can lease it to a shop.


----------



## Wizard69 (Aug 10, 2018)

Entropy455 said:


> Not resolved (yet).
> 
> The chuck seems to be a traditional D-type locking mechanism (non-air). My best guess is that air is somehow used within the clutch/gearbox/transmission.
> 
> Right now all of my effort is on the phase converters. It is going to cost me about 2500 bucks to build a pair of 40 hp converters - provided I use SSRs in lieu of contactors. I'll take pictures of the converter construction. . . .


I'd resolve the issue of the air usage first.    A lot of these big lathes had a clutch brake assembly either on the motor or on the power input to the gear box.   If so you would see a pretty huge difference in start up effort if you have the clutch off at motor start.   That may mean being able to start the motor with one phase conversion motor instead of two.   If so (we don't even know if it is possible) you would save the cost of the additional motor and the associated electronics.


----------



## DJP (Aug 10, 2018)

This lathe for hobby use makes the discussion of shellac checks pretty insignificant.

Have you considered hooking up air pressure to see what moves or what leaks? That may help.


----------



## Entropy455 (Aug 10, 2018)

I don't even know what air pressure to feed it. . . Most industrial tool air is around 90 psig. But what if this thing only requires reduced 20 psig air? I'm really nervous energizing this machine, without a schematic diagram, or at least OEM operating instructions.

The electrical enclosure has almost a dozen large electrical contactors. I'm assuming the machine is wired for 460 Volts, as it would be highly unusual for a lathe of this size to be wired for 230 Volts. I can rewire the main spindle motor for 230 Volts, however the lathe's existing contactors might not be rated for twice the operating current. I might simply purchase a 3-phase step-up transformer. We'll see. . . . . Again, I haven't torn into the electrical yet. I'm still trying to find OEM literature/operating instructions. I'm also gathering parts for the phase converters. Even if I "can" run this thing on a smaller converter, I want to power it properly (It's my OCD).

Below are my medium lathe, small lathe, and my large mills. I had to build a gantry crane to move the horizontal mill, because it was beyond the capacity of my forklift. Needless to say, my large lathe is beyond the capacity of both my forklift, and my gantry crane. . . .


----------



## Richard Carlstedt (Aug 11, 2018)

Time out ..We had an Axelson in our Newark California shop up until the early1990;s 
It is a fine lathe. our Plant air was 90 to 120 PSI. I can not recall why it needed air, except that it had a clutch assembly. Most all our lathes had Auto Lube systems , by Bijur or Lincoln so that is most likely the reason and if the lube system did not respond to a micro, you got no rotation.
Time out note is for the reason to have two RPC's ???  ( I think you wanted to start up sequentially ?) 
If the motor can idle ( and I am sure it can ) you only need the make the motor have a self starter and use a 5HP (single phase ?) motor coupled to it with a over-running clutch . The 5 HP will easily get it up to speed, and then there will be little in-rush of current on the larger lathe motor.
I think you really should investigate a "Phase Perfect" unit for your application.
Rich


----------



## Richard Carlstedt (Aug 11, 2018)

Forgot to say our shop was 240 Volts 

Rich


----------



## Entropy455 (Aug 12, 2018)

My reason for two converters - 

It takes 80 horsepower of phase converter to start a 40 horsepower gearhead lathe. A single 80 horsepower phase converter may trip my 200 amp main breaker, simply by starting the converter.  Additionally, when making heavy cuts on a single converter, I'll be drawing upwards of 180 amperes - which leaves me very little reserve for other loads in the shop.

This is why I'm installing a second 200 amp panel in my shop. One 40 horsepower phase converter will be connected to one 200 amp panel (via 150 amp breaker), and the other 40 horsepower converter connected to the other 200 amp panel (again via 150 amp breaker).

Only one converter will have an automatic start function (i.e. momentary starter caps wired into the circuit). I will automatically startup one 40 horsepower converter, than energize the second converter - then I can safely start the lathe. I'll be able to take heavy cuts, to light cuts, to everywhere in between - and I won't have to worry about tripping either of the mains, because the load will be split between two service panels.

Unless I can get a 40 horsepower phase-perfect for under 2500 bucks, I'll be sticking with rotary phase converters.


----------



## Entropy455 (Nov 7, 2018)

Today I picked up a matched pair of 40 horsepower electric motors - for building my rotary phase converter for the big lathe. The motors set me back 600 dollars for the pair (purchased at surplus auction). Next I need to purchase contactors, and a few boxes of motor caps. I'll take pictures of the construction process. . . . .


----------



## Ghosty (Nov 7, 2018)

Entropy455, done a quick search and came up with this, http://www.vintagemachinery.org/mfgindex/detail.aspx?id=2137&tab=3  Don't know if it will help.
Another one  https://ozarktoolmanuals.com/machin...eavy-duty-engine-lathes-service-parts-manual/
Cheers
Andrew


----------



## Entropy455 (Nov 8, 2018)

In 1954, Axelson merged with USI-Clearing - a company known for building monster size presses & shears. This Axelson-Clearing Model 2516 lathe was the product of this company merger. The US Navy paid top dollar for this lathe back in the day. Sometime in the early 1980s, the Navy donated it to a college. I purchased the lathe at-auction from the college in July, for essentially scrap value. No one at the college had actually used it for over 25 years - which is why they sold it. The college staff knew almost nothing about the lathe. As far as getting information from the Navy - unfortunately the procurement/contract records are likely hard-copy, and long-gone (i.e. were probably never scanned electronically). USI-Clearing shut down their lathe manufacturing due to poor sales. It was shortly after the war, where most companies were already tooled up with heavy-duty machines, and there simply wasn't a demand for more large lathes in the 1960s. I've read that USI-Clearing is still in business today making parts for the oil industry (well heads and pump equipment). I'm going to make a last-ditch effort and contact them - to see if they've got copies of original lathe literature. We'll see. I might just have to do this old-school, and simply turn it on to see what happens. . . .


----------



## ignator (Nov 9, 2018)

You're probably are going to need to make your own wiring diagram for the lathe.  If there is a MIL specification number, you might be able to find the attached manual. But I bet it will not be online to the general public. My former place of employment had paid access to these library's. 

Your initial post about a "large" hobby lathe, it's HUGE. I bet the process of moving it from  the school to home has a great story. 
Interesting horizontal mill with a built in rotary table.
Nice building to house your shop.
I've had good luck with VFDs from single phase 240, powering 7.5HP motors.  The drives for these are 10HP, and as I'm never going to use the full power of the machines, the drives don't have to have 2x the power rating. I started with a RPC made from a 5HP motor. It didn't have the guts to start the 7.5HP lathe with no load. And ended up having some sort of overvoltage that caused a short in one of the motor contactors (cheep plastics probably contributed to this, but the short was between phases, and on disassembly, I could not see the carbon track). 
I don't think the running current will be an issue with your contactors. Are the coil voltages line, or is there a lower voltage transformer for running the controls? If that transformer has different input voltage taps, then the lathe was intended to run on 220/440. A dozen contactors, there must be some relay logic usage, as my large lathe (2004 era) only has 5.


----------



## DanP (Nov 9, 2018)

"Hobby" lathe, that's the biggest hobby lathe I have ever seen or imagined!


----------



## mcostello (Nov 10, 2018)

Depends what Your hobby is!


----------



## MachineTom (Nov 10, 2018)

You may consider posting on the Practial Machinist board. Folks there a mostly industrial sized tools. Most likely someone can help you  there.


----------



## Entropy455 (Nov 10, 2018)

I made a post on Practical Machinist Boards - not one reply. . . .


----------



## ignator (Nov 10, 2018)

Entropy455 said:


> I made a post on Practical Machinist Boards - not one reply. . . .


They are extremely 'sensitive' to post titles. I would ask them again there with something like;
"Axelson-Clearing Model 2516 Air chuck operation question".  I see your post there from July. Also ask about a schematic or manual in the post, but describe how your wanting to understand the supply pressure, and any issues about operation. They want very descriptive titles, and machine details so they don't have to ask "20 questions".


----------



## ignator (Nov 10, 2018)

Entropy455 said:


> I made a post on Practical Machinist Boards - not one reply. . . .


Also don't say anything about "HOBBY" they don't play well with us.


----------



## Entropy455 (Nov 10, 2018)

I'm about to pull a permit for my second power panel. I figure I need 300 amperes at 230 volts to adequately power my phase converter (150 ampere breaker for each converter-motor).  This will permit me to operate my lathe up to about 30 horsepower (the lathe has a 40 horsepower motor).

If for whatever reason 30 horsepower is not enough - and I honestly can't see that happening, considering the massive cuts required to even draw 10 horsepower - I'll bump the isolation breakers up to 200 amperes each - which will get me an honest 37 horsepower into the cutter. My gut tells me that 30 horsepower will be plenty.

My transformer is 37.5 kVA, which I share with my neighbor. My garage has 350 KCML feeders (185 foot run).  My wires are fine, but the transformer may be too small - not for running the lathe, but for starting it. The lights might flicker every time I start the lathe, which will be a no-go for my wife, and for my neighbors. If this happens, I'll pay the power company to replace the 37.5 unit  with 50 or 75 kVA transformer.

Before I worry about the air supply, and what it does, I'm going to focus on resolving my power-supply issues first. . . . (i.e. building my phase converter)


----------



## Entropy455 (Nov 10, 2018)

Point taken ignitor - I'll repost my question - more specific & detailed, less the word hobby. . . .


----------



## ignator (Nov 10, 2018)

Entropy455 said:


> I'm about to pull a permit for my second power panel. I figure I need 300 amperes at 230 volts to adequately power my phase converter (150 ampere breaker for each converter-motor).  This will permit me to operate my lathe up to about 30 horsepower (the lathe has a 40 horsepower motor).
> 
> If for whatever reason 30 horsepower is not enough - and I honestly can't see that happening, considering the massive cuts required to even draw 10 horsepower - I'll bump the isolation breakers up to 200 amperes each - which will get me an honest 37 horsepower into the cutter. My gut tells me that 30 horsepower will be plenty.
> 
> ...


Should be interesting to hear if inrush current is not a problem. I'm not aware of a VFD that can power a 40HP motor from single phase. I think the issue is they have very good phase loss detectors to protect the input diodes from failure. Someone may have more knowledge with this, as I've never used a VFD greater then 10HP from single phase, to drive 7.5HP motors. But It's clear your going down the RPC route, hope that is fruitful. Unless you're are going to do serious material removal rates, I can't imagine needing more then 5HP of spindle power. I suspect the 40HP just idling uses more then 5HP of power, most of that just inherent losses.
Hope all goes well.


----------



## Entropy455 (Nov 10, 2018)

Inrush current will be the dominant problem. The rule-of-thumb is that the converter should be twice the size of the machine's motor - which is why I'm building an 80 horsepower converter.

I estimate I'll draw 7.6 horsepower worth of electricity at idle, costing me 68 cents per hour at idle - and that's just to run the converter.

I'll take & post pictures of the phase converter construction process. I'll also post pictures of my design schematic. My experience is that rotary phase converters work very well. With an 1800 rpm fully-enclosed motor - if you select quality contactors and quality capacitors for the controls (and remember to grease the motor bearings once per year), a rotatory phase converter should run 60,000 hours before maintenance is required (essentially lasting forever).


----------



## ignator (Nov 10, 2018)

Entropy455 said:


> Inrush current will be the dominant problem. The rule-of-thumb is that the converter should be twice the size of the machine's motor - which is why I'm building an 80 horsepower converter.
> 
> I estimate I'll draw 7.6 horsepower worth of electricity at idle, costing me 68 cents per hour at idle - and that's just to run the converter.
> 
> I'll take & post pictures of the phase converter construction process. I'll also post pictures of my design schematic. My experience is that rotary phase converters work very well. With an 1800 rpm fully-enclosed motor - if you select quality contactors and quality capacitors for the controls (and remember to grease the motor bearings once per year), a rotatory phase converter should run 60,000 hours before maintenance is required (essentially lasting forever).


Seems your well informed.
I started my shop out with a RPC I made from a 5HP 3600RPM motor. Worked OK, but very noisy in my 8x30 shop space. It also was a TEFC motor. I got it surplus, where it had been rebuilt at one time with new ball  bearings, but whomever did this, did not remove the shield from the zerk side of the bearing. Pumped the bell housing full of grease.

But I don't have anything like a 40HP motor to spin.


----------



## Entropy455 (Nov 10, 2018)

There are three advantages of using an 1800 rpm motor for building a phase converter.

(1) they spin slow (compared to 3600 rpm) which means extended bearing life, and less audible noise during operation (fan, hum, etc)
(2) HP for HP, they have higher rotating inertia (more moving mass) than 3600 rpm motors, which provides an extra kick when starting other loads
(3) an 1800 rpm motor has appreciably more copper - which means lower impedance, which means extra kick when starting other loads
Downside is the extra copper drives the cost of the motor up.

To reduce operating noise, always use rubber isolation mounts (i.e. thick rubber sheets/sections) between the converter motor and the converter frame/chassis. Just make sure both the motor, frame, and lathe are properly grounded.

The new solid state drives are pretty trick, but expensive. A 40 horsepower unit is WAY outside of what I'm willing to spend.

I was contemplating mounting a 3-71 Detroit diesel on the other side of the shop wall, and drive the lathe directly at 1800 rpm via pto/belts (replacing the 40 hp lathe motor with a simple belt-driven jackshaft). However I cannot stand the idea of having to start a combustion engine to run my lathe. Starting a phase converter is somewhat of an irritation in itself, but at least I don't have to feed it diesel, change its oil, or keep its battery charged. . .

3 phase power ends about 2 miles down the road. It would cost well over 100 grand to bring it to my house. Maybe if I win the lotto. . .? Until then, rotary converters are the ticket - especially when constructed from scratch to keep costs down.


----------



## ignator (Nov 10, 2018)

Entropy455 said:


> There are three advantages of using an 1800 rpm motor for building a phase converter.
> 
> (1) they spin slow (compared to 3600 rpm) which means extended bearing life, and less audible noise during operation (fan, hum, etc)
> (2) HP for HP, they have higher rotating inertia (more moving mass) than 3600 rpm motors, which provides an extra kick when starting other loads
> ...



The 3600RPM motor presented itself for a very low surplus cost.  I wanted a 10HP motor, but there was only one surplus store in town, and induction motors were only seen once by me with the 5HP motors. It was an avionics company, so most surplus was electronics.
I should have  mounted it (the RPC) on the other side of the shop wall for noise abatement. Once the big lathe would run on a VFD, it pretty much ended my RPC days. I have replaced every single phase motor in the shop with 3ph, and a dedicated VFD for each. They are commodity items now, but I did get most of them off eBay or Craigs list. 
I don't have your 40HP problem. The big advantage is soft start, and the ability to program in the Hz to RPM spindle conversion constant, and have the LED display show spindle RPM where I leave the belt setting fixed. 

You aren't doing this shop upgrade as a hack (reading your description), given a pretty big investment in a higher ampacity panel. I assume you have some pretty costly wire runs, along with service entrance connections. And procuring 2 40HP phase generator motors didn't just walk into the shop. 
That is a nice looking gantry crane build.
The one thing that my big lathe has is a large through spindle hole. My use is repair parts, and I'm assuming you didn't invest in your big lathe to make miniature models, and will enable some tasks beyond your other lathes (and it's hard to say no when quality iron falls in your lap).


----------



## 99Norton (Nov 11, 2018)

Now that you have bought your motors you could have a look at https://unique3phase.com
Has a good breakdown on pro & cons of different types of systems.


----------



## Wizard69 (Nov 11, 2018)

I'm still not convinced that your really need two 40 HP phase converters to run this lathe.   Mostly due to lathes this size having some sort of clutch/break assembly so the motor starts at almost zero load.   There might also be a soft start capability within the controller.   

In any event you may very well have to ring out the entire control panel and generate an electrical schematic of the electrics to really be able to use the machine.    If you haven't done it before this can be a lot of work.    It is even worse if none of the wires have readable wire numbers.   It isn't impossible just be prepared to chase down lots of wiring.    As far as the big contactors go you should have a pair (assuming reversible spindle here) for the main motor, a coolant pump contactor, and possibly a contactor for driving the saddle rapid if any.   So three contactors going to motors of some sort.   I never worked on this brand of lathe so there are other possibilities like a shift assist motor, but three motor contactors seems about right.    There is a remote possibility that the motor starter is far more complicated supporting dual speeds, soft starting or DC braking, if that is the case your controls can be far more complicated.

Considering the era of the machine and the original buyer, you likely have a master control relay (MCR), contactor as part of the E-Stop circuit.   There are likely relays connected to air pressure switches.    One thing I noticed is that you have the electrical panel backed up to the barns wall, you will grow to regret that.   You will want regular access to the panel for maintenance.    Beyond that is you need code compliance you will need most likely 4-6 feet of clearance behind the panel ( I forget the exact distance for that voltage and power level).   In any event post a picture of the panel it might be possible to identify some of the contactors and other components in the electrical panel.

By the way the more pictures you post the more it looks like you got a machine in excellent condition.   Consider yourself lucky.


----------



## Entropy455 (Nov 11, 2018)

The reason I'm using (qty 2) 40 horsepower phase converters, is because a single 40 horsepower converter might not cut it (i.e. unacceptable voltage drop on the generated phases will stall the motor being started). The industry rule-of-thumb for rotary phase converters is 2:1, where the converter is twice the size of the largest motor being started. If the motor being started is heavily loaded (i.e. no spindle clutch on my lathe, or an air compressor, or a conveyer belt, etc) the recommended ratio jumps to 3:1.

For lathe positioning within the shop - I've got (qty 4) 12-ton equipment skates and a pair of bottle jacks that I purchased specifically for moving this lathe around. I'm contemplating moving the ​lathe to the center of the shop, and moving my milling machines along the wall. Another option would be to move my car-lift towards the front of the shop, and move the lathe further back along the wall. I haven't decided yet. . . .

I recently discovered that high current contactors are very expensive. The contactors I need for building my large phase converter cost about 500 bucks each - and I need three of them. . . . My 10 horsepower converter parts were cheap in comparison.


----------



## ignator (Nov 12, 2018)

Entropy455 said:


> I recently discovered that high current contactors are very expensive. The contactors I need for building my large phase converter cost about 500 bucks each - and I need three of them. . . . My 10 horsepower converter parts were cheap in comparison.


Entropy, I'm curious what your contactor specs are.
For [email protected], looks like 30Kw contact rating.
Ebay has 3 used contactors @ $70 ea;
https://www.ebay.com/itm/ABB-EH-110...=item285e0e818b:g:3ysAAOSwyARbLai6:rk:13:pf:0
Some brand new from China $21 each;
https://www.ebay.com/itm/CJX2-9511-...h=item3d44406e74:g:phQAAOSwcp1Zjlpl:rk:1:pf:0

I bet new name brand is very pricey.


----------



## Entropy455 (Nov 12, 2018)

The converter contactors must be rated for a single-phase horsepower equivalent - which is a little over two-times the 3 phase current rating. A contactor for starting one 40 horsepower converter should be about 250 amperes. It wouldn't hurt to go a bit larger, because the bank of capacitors wired in parallel with each motor are a very low impedance dead-short during startup (further compounding the surge-current problem). A 250 amp contactor is the absolute minimum I need, and even then - it's on borrowed time.

www.elecdirect.com has some nice 3-pole 265 amp contactors for 450 bucks (plus 60 bucks for the control-coil). For extended life, I'd rather have the 330 amp unit, but it's 572 dollars (plus coil). . . . ! This particular brand is from India, and it seems to be the best value that I've found thus far.

I am very hesitant to purchase used contactors (I'm not saying that I wont). It's just that sometimes electrical equipment is taken out of service because it's old and worn out - and not every used-contactor salesman is honorable. . . .​


----------



## Entropy455 (Nov 12, 2018)

Here's two pictures of my phase converter motors. These set me back 600 dollars (after tax) for the pair. Ten identical motors went up for sale at once, sold as surplus by Boeing. They look almost new - with exception of aircraft factory mystery dust (pictures are as-received). The paint on the sheaves is hardly worn. I'm assuming they were lightly used ventilation fan motors. The motors are 16 inches in diameter, and weigh about 650 pounds each. These are 1800 rpm, 40 horsepower, 230/460 volt 3-phase.

I'm going to build a frame to mount the motors in a stacked configuration - to save floorspace. I'm also going to cut the motor shafts off, to minimize exposed moving parts.


----------



## ignator (Nov 12, 2018)

Those motors are a pretty good deal, I've always wanted to stop into their surplus store. The company I worked for was a major avionics supplier to them.

I think you can get what you want from eBay new in name brand contactors. They may be shipped off shore (China where we exported all our IP too).

Here is a 250amp, that you can get multiples of Schneider electric $104;
https://www.ebay.com/itm/Schneider-...692880?hash=item3d61cae8d0:g:ZfkAAOSwx3NZZYpi

Here is a 330amp Telemecanique $350;
https://www.ebay.com/itm/Telemecani...=item260944b4ad:g:6DQAAOSwtytZpsmn:rk:37:pf:0

$300
https://www.ebay.com/itm/TC-SHAMROC...IAAOSwEaBaA0kI:rk:100:pf:0&LH_ItemCondition=3

I did a quick search, and for only new, as I agree, you don't know what damage the contacts have from previous life.
But you probably ordered these already. So my post is probably just noise.


----------



## Entropy455 (Nov 12, 2018)

I haven't ordered contactors yet. I appreciate your (and other's) help. Continued input is welcome. . ..

Another option I have is to use high-current SSRs, which are inexpensive (about 40 dollars, in lieu of hundreds of dollars for contactors). The problem is that SSRs generate 1.5 Watts per ampere, and I need (qty 2) per converter. Basically I'll be dumping 600 watts into a heatsink when the lathe/converter are running. On the plus side, there's no moving parts with SSRs. I don't want to go the SSR route, but I don't want to spend 1.5 grand on contactors either. Used or old non-used surplus might be my best route.

I'm going to order the parts I know I need - starter caps, run caps, supply breakers, etc. I still need to build a frame for the motors, and pull a permit for the second 200 amp panel in the shop - thus I've got a little time to continue shopping for contactors. . . .


----------



## ignator (Nov 12, 2018)

I always search eBay 'price plus shipping lowest first' I saw those SSRs, in 3 phase. I'd worry about overload, and them blowing short. And there are so many counterfeit SSRs from China using name brand logos.  600watt heatsink is crazy dissipation. I've only used them in the shop for 3Kw radiant heaters, and just bolt them to an aluminum sheet. I had one of the Fotek brand counterfeit fail last year and it was 25amp rated, 2x the load current.
Is your RPC design to start one of the motors, then use the generated phase to start the 2nd motor? I've never looked at multiple motor RPC topologies. 
I assume your in the Seattle area, and get to work through winter without frozen ground. My wife's parents lived up in Anacortes.

I tripped on this from eBay
https://www.ebay.com/itm/30KW-40HP-...h=item28638455d6:g:9DYAAOSwDkVaF-On:rk:5:pf:0
I was shocked to see this with single phase input. I know this is not your path.


----------



## Entropy455 (Nov 14, 2018)

The first 40 horsepower converter will start automatically - with one contactor for switching power, and another for engaging the start capacitors. The second converter will start off the first, with just one contactor switching power. The generated legs are hard-wired, thus no starting caps are needed to start the second converter. Both converters will have run caps installed, sized for taming the voltage on the generated phases. The load "should" be balanced between the two converters - seeing as they're identical impedance (i.e. matched motors).

My biggest fear of SSRs is they tend to fail closed. . . .

People love the new variable frequency drives with soft start. I must admit, I'd probably fall in love with them too - if I had one. . . Another problem with a fancy digital motor controller for my lathe, is that I've got at least three 3-phase motors - one 40 horsepower for the spindle, and two smaller motors - one for the coolant, and one which I'm assuming is for a pressurized headstock lubrication system. Don't get me wrong, the obstacle of powering the smaller motors separately could be overcome - but I'm going to stick with an old-school solution nonetheless - i.e one large rotary phase converter.


----------



## ignator (Nov 14, 2018)

Entropy455 said:


> but I'm going to stick with an old-school solution nonetheless


I understand, I was more shocked to see a 40HP VFD with single phase input. I've never seen this before. Everyone required 3Ph input, and would not operate because of a phase loss detector. I think this seller also indicated it was a sensorless vector drive, which is a requirement (for high torque low speed operation) from my experience. 

I used a 2nd VFD that was cheep (fractional HP) for the coolant pump on my lathe. But I've never put any coolant in the sump. Just seems messy. I've only ever used it on the mill when doing side milling with an end mill in steel (after burning up a few). I use oil coolant (Mobil Gamma), as something about water soluble stuff seems like a recipe for rust, if you don't remove the setup and wipe down the table (as well the biological experiment in the sump). The oil splatter on the floor was remembered, strange thing the stuff that didn't get cleaned up, evaporated within a week. The other issue I have with coolant, is the vaporized smoke, I believe this is very bad for your lungs. Yet I see many youtube videos of pros having a closed shop with smoke in the air.


----------



## Entropy455 (Nov 15, 2018)

I'm going to hijack my own post, and ask a VFD question - 

Is an inverter-duty, and vector-drive rated motor the same thing? I.e. must an electric motor be rated for inverter-duty/vector-drive, when used with a VFD?

The reason I ask - my little lathe (on page one of this thread) came with an old-school VFD, it works ok. . . . At lower speeds the motor torque basically disappears. It's a somewhat variable speed motor. I know that I'm not supposed to take heavy cuts on a little lathe, but the darn thing has trouble cutting plastic it's so underpowered. My plan is to eventually put a DC motor on it, with a PWM. However I'm starting to think a VFD with 3 phase is the way to go.

Must I purchase an inverter duty motor, or will a quality heavy-duty 3-phase motor work?


----------



## Wizard69 (Nov 15, 2018)

I understand your need for high amperage contractors but please avoid any of the Chinese offerings.  The few Chinese controls I’ve worked with have been crap.  

Your capacitor inrush current will be huge, it may pay to create a precharge / soft start solution with some really large resistors.   Having a contractor blow up is no fun at all.  The worse one I saw was due to a rotor lock up on a 30 hp compressor.  The capacitor bank just makes your startup currents even worse so having a bit of margin is in order.


----------



## Entropy455 (Nov 15, 2018)

I'm half tempted to go old-school and use some giant knife switches - and simply polish off flash marks with sandpaper every few months. . .

My 10 horsepower converter has 80 amp contactors, which seem to be holding up just fine.

I'd like to find some 700 or 800 ampere contactors (obviously used) - which would provide plenty safety-factor.


----------



## ignator (Nov 15, 2018)

Entropy455 said:


> I'm going to hijack my own post, and ask a VFD question -
> 
> Is an inverter-duty, and vector-drive rated motor the same thing? I.e. must an electric motor be rated for inverter-duty/vector-drive, when used with a VFD?
> 
> ...



Yes inverter-duty and vector-drive are the same thing (vector drive should have an encoder for position control, otherwise it's just semantics). The difference (between standard motors and inverter duty) is better electrical winding insulation. 
I've had very good luck with old antique motors, and modern VFDs, which control the edge rate so they are not overly fast. This limits the voltage spikes that cause electrical insulation failure. I have a 1940's motor that is part of a Lima overhead drive line attachment to my 1930's Rockport horizontal mill. I don't use this machine too much. My vertical mill has a 1960's motor, and 100s of hours of time using a Hitachi VFD.
This has been my understanding of the issues when VFDs first came to the market place, their edge rate was too fast.

I've said this recently about sensorless vector VFDs, they produce lots of torque at very low Hz drive of the motor. I learned this by purchasing TECO standard VFDs included with a 1HP inverter duty motor 20+ years ago. The drives would cog the motor shaft (jump discrete movements) and would stop spinning the motor below 20Hz or so. 
Check out below link for motor and VFD packages. I've found them to typically have the best prices on quality VFDs.
https://dealerselectric.com/motor-drive-packages.asp


----------



## Entropy455 (Nov 15, 2018)

Dealerselectric does have freakishly low prices. Thank you very much for the link.

https://dealerselectric.com/Package-NAT1-5-18-56-and-L510-202-H1-U.asp

Assume for the moment I purchase the above combination for my small lathe. The advertised frequency is 0-650 Hz. First obvious question - is it safe to turn a 1,800 rpm motor at 19,500 rpm? My assumption is absolutely not - thus what is a safe upper speed? 3,600 rpm? 4,500 rpm?

If I assume 4,500 rpm is the safe upper speed for the motor, I could direct-couple the motor to the spindle with a  2.25:1 pulley reduction, which would give me a spindle speed from 1200 rpm, down to ??? I.e. what is the expected low-end performance??? The literature is silent (or I simply don't know where to look) . . .


----------



## ignator (Nov 15, 2018)

Entropy455 said:


> Dealerselectric does have freakishly low prices. Thank you very much for the link.
> 
> https://dealerselectric.com/Package-NAT1-5-18-56-and-L510-202-H1-U.asp
> 
> ...



I always set up the VFD for max 3600 RPM. Basis is that the same rotor is used for 4 pole as 2 pole, so it is designed to operate at 3600.
The *L510-202-H1-U *manual has one section for setting the drive up for sensorless vector page 4-21 of the manual. SLV mode. I've not used this model of TECO.
https://www.tecowestinghouse.com/Manuals/L510_instruction_manual.pdf


----------



## Entropy455 (Nov 15, 2018)

The motors being sold in the inverter/motor combination packages at dealerselectric are not specifically inverter-rated. What are the implication of this? Is motor life simply reduced? Is the significant wear & tear on the motor from sustained low rpm operation, or is operation at any rpm hard on the motor with a digital drive?

Here's where I'm going with this - the 40 horsepower inverter you linked in post #42 would likely power my lathe, maybe from a single 200 amp panel (rated input current is not listed anywhere). In theory, I could use my existing 10 horsepower rotary phase converter to power the coolant pump & lubrication pump - and electrically separate the 40 hp spindle motor onto the inverter. At 1500 bucks, this is a much better cost option than building an 80 horsepower converter. I had no idea inverters were available so large, and so inexpensively.

The big question is this - do I need to replace the 40 horsepower motor in my lathe with an inverter-rated motor, or can I use the stock motor? If replacement with an inverter-rated motor falls under the "should replace" or "must replace" category, I'm back to building a rotary phase converter - because a 40 horsepower inverter-rated motors start at about 4 grand. . .


----------



## ignator (Nov 15, 2018)

Entropy455 said:


> The big question is this - do I need to replace the 40 horsepower motor in my lathe with an inverter-rated motor, or can I use the stock motor? If replacement with an inverter-rated motor falls under the "should replace" or "must replace" category, I'm back to building a rotary phase converter - because a 40 horsepower inverter-rated motors start at about 4 grand. . .


The big thing with VFDs is to not have a long connection between the motor and the VFD as the long connection enables a larger standing wave peak voltage. This voltage is what damages the motor winding insulation. My connections are less then 6 feet.


Here is one such article for input;
https://www.energy.gov/sites/prod/files/2014/04/f15/motor_tip_sheet14.pdf

I did an internet search using "are inverter duty motors required for VFD connection".

I doubt that you will ever use the 40HP of the lathe, but I don't know if you intend to use that oil well lathe for commercial removal rates. The inductive reflection voltage is a function of the current pulse value, so low torque operation keeps the V=L di/dt impulse voltage within the insulation of the motor. Also operation with 220VAC, keeps these peaks lower then if 440VAC operation is used.
I really don't think you will have any problems unless you push the lathe cutting power to the limits of the motor, and using 440 operating voltage.
Newer standard motors have improve varnish winding insulation. Your 1960's 40HP is such a motor.


----------



## Entropy455 (Nov 15, 2018)

I've been reading up on the high voltage spikes associated with long wire runs. If I mount the inverter on the side of my late (adjacent to current control panel), my wire run to the motor will be about 5 feet max.

I'm going to give this a shot. An added bonus is that I might not have to install a second 200 amp power panel (or purchase 1500 dollars worth of contactors).

And look at the bright side - if I do burn out the lathe motor, I've got two nice 40 horsepower ready-spares. . . . .


----------



## ignator (Nov 15, 2018)

I integrated my VFD to use the apron mounted FWD/REV lever. As well the foot brake stops the VFD. 
I never made a drawing of this, but I know that the VFD is connected directly to the motor so the FWD/REV contactors are not used.
Switching the connection between the VFD and motor is forbidden. Voltage spikes large enough to blow up the output transistors can occur. 
I see the vendor on eBay will furnish a user manual if you message them. That may be worth seeing how well it's been translated to understandable usage by you.
Sorry I interrupted your project. Oh, and the shipping is ~$275, don't know if you your ebay page shows this.


----------



## Entropy455 (Nov 16, 2018)

I'm not upset about changing my design plan.

A VFD is obviously a better route. My failing to recognize this would make me a grumpy old man - and I'm not there yet. . . . .


----------



## Entropy455 (Dec 2, 2018)

I'm hesitant to purchase the VFD from China (Part number V8-G 2S 30R0G).

The price is good (almost too good to be true). A VFD that will drive a 40 horsepower motor with single phase input is rated for 100 horsepower on 3-phase. These 100 HP units are quite large, and quite expensive ($3,500 typical starting price).

I'm worried that the V8-G 2S 30R0G unit from China will be rated for 40 HP with 3 phase input power, and actually only 15 HP with single-phase input. It might be worth it for me to simply pay double, and purchase a 100 HP unit now - one that I know will drive a 40 HP motor with single phase input power. . . . . The China unit cannot be returned, and I do not like to purchase parts twice. . . .

I'm going to request the V8-G 2S 30R0G manual nonetheless - to see if there's any fine print on the input-power performance. My gut tells me the VFD route will cost closer to 4 grand. Is it worth it????


----------



## gunner312 (Dec 2, 2018)

Axleson is an OUTSTANDING machine, I used to run one that was about the same size but that was a few years ago. Great machines right up there with Cincinati and Clausing-Colchester. One thing I remember is that the spindle bore was about 8"  great for doing shafting. I don't have anything that big anymore, but I have a Wam that needs 440 and I use a 220 3phase converter to a 440 Transformer to power it up but then it's just 10 HP. Most of the time the Air interlocks are low pressure (As I remember or mis-remember as the case may be, usually about 45 PSI but could be as high as 90 psi) The reason for low pressure was so that when the system was under heavy use, you could still run the lathe as long as pressure was above 45 psi. Outstanding Machine. I just sold my big lathe it was only 24 X 144. Good luck
with the Axleson.


----------



## ignator (Dec 2, 2018)

Entropy455 said:


> I'm hesitant to purchase the VFD from China (Part number V8-G 2S 30R0G).
> 
> The price is good (almost too good to be true). A VFD that will drive a 40 horsepower motor with single phase input is rated for 100 horsepower on 3-phase. These 100 HP units are quite large, and quite expensive ($3,500 typical starting price).
> 
> ...


My reading of many posts about VFDs is that you have to double the HP rating to ensure the input rectifier is large enough for single phase.
I see in their eBay auction listing a diagram that someone took the time to show a single phase circuit breaker connected to this VFD.
http://rover.ebay.com/rover/1/711-5...0001&campid=5338413729&icep_item=173468308950
I've repeated the link here for others to see the item.
If you can find a 40HP VFD with the DC bus available as terminal connections, you can add your own single phase rectifier and capacitor filter and not use the built in diodes. I don't see this on this on this drive.
I do understand your hesitation, as $1650 is not cheep. But China can do that price as they don't pay their Engr's the same pay scale, and their overhead has no comparison to any first world country. 
Hope they provide a manual in PDF via a message link. And it's translation validates single phase input at rated current.


----------



## Entropy455 (Dec 3, 2018)

This I can do - a full-bridge rectifier, a healthy bank of capacitors, and a series-choke for voltage spikes.

I found a link for sizing VFD power supply capacitors for single phase applications: https://kebblog.com/select-single-phase-vfd/

The question is - are there VFDs were the DC bus is accessible for normal external power connections? I suppose I could always open the unit up, and jumper to the backside of the rectifier.

Another question: the 40 HP VFDs on dealer's direct - some of them are advertised for pumps and fans, where others (more expensive) mention lathe applications. Will these entry-level VFD advertised for pumps and fans work satisfactorily? Example: https://dealerselectric.com/F510-2040-C3-U.asp    I honestly don't need super fancy control features - I just need the ability to start & stop my lathe. . . . That being said - not having to modify the VFD internals would be a plus also (i.e. having a terminal connection for external power supply).


----------



## ignator (Dec 3, 2018)

Entropy455 said:


> This I can do - a full-bridge rectifier, a healthy bank of capacitors, and a series-choke for voltage spikes.
> 
> I found a link for sizing VFD power supply capacitors for single phase applications: https://kebblog.com/select-single-phase-vfd/
> 
> ...


I've found this same VFD on Aliexpress;
https://www.aliexpress.com/store/pr...phase-0-380V-out-60A/1155094_32842700732.html
This shows the same artwork and also indicates single phase power input.
I've found the 400VAC class of this drive with 3 phase in for $613, but could not find the 2ooVAC class with single phase input,  for a low cost. You may find it for a lower cost with your search.
https://cntopstock.com/30kw-40hp-30...vac-input-3phase-0380v-output-60a-p-4856.html

First Q; Yes, the manual will have this detailed.  I've seen this on my 10HP TECO 7200 drive. And the harder way would be to open the unit up and connect into the existing bus, probably difficult to do with the large current and keeping the connection solid and low resistance.






Second Q;
The fans and pumps VFD only have V/f control, as they do not need to provide high torque at low RPMs, as with fans and pumps the torque drops off with speed. This sort of drive will work perfect for lathe operation if you don't run the speed down to single Hz, and want high torque. This drive still provides soft start.
The other control is sensorless vector control (there are others that use encoder feedback) and this provides up to 200% of torque at near zero Hz. And as you've found they charge extra.


From all my looking at this eBay drive and the same on Aliexpress, and sites that show phase converter VFDs, I think you can trust the single phase input description as accurate.


----------



## ignator (Dec 3, 2018)

Also, you do have to make sure the drive is for 220VAC input, I see lots of the 440AC input units on eBay, but they will not operate at 220VAC input, and will show an error code of low line input. To bad, they are lower cost as folks like me only want the 220 input models.


----------



## Entropy455 (Dec 3, 2018)

Today I called and spoke with an engineer at Teco - specifically about purchasing a 40 horsepower VFD, and running an external bridge rectifier, with extra capacitor bank - and jumpering it into the VFD. Here's what he said (in no particular order)

Most, if not all, Teco VFDs sill require an AC input to drive the electronics (small stepdown transformer tapping off the AC input). This design is preferred over trying to switch a 330 plus volt DC bus down to TTL voltage. Thus I'd need to electrically lift, or otherwise power this transformer with AC, while also separately feeding the DC bus (an internal modification to lift the input rectifier).

The DC bus terminal connections are taps, and are not intended to carry the full bus current. Thus I need to hard-wire/jumper the external power supply directly into the internal bus bars.

The typical weak link in the design (the reason for derating) is the DC ripple, and not necessarily the diodes. More specifically, the capacitor bank is too small to filter a single-phase ripple. I might be able to simply jumper in extra capacitance, and use the stock rectifying diodes - depending on the VFD unit I select.

He recommended against using a variable-torque drive for a lathe, with the assumption that I'd desire the ability to slow the motor and still make cuts.

A constant-torque VFD is a harsher electrical load on the DC bus, compared to a variable-torque mode - again, with DC ripple being the ultimate performance limiting variable - where the VFD is trying to switch power that simply isn't available.

Needless to say, the context of our discussion was clearly reiterated - in that Teco doesn't advise or condone ANY of the above modifications. This was purely a could it be done hypothetical discussion.

I still haven't made a decision as to what I'm going to do. . . . I suppose the next step is to price out a bank of electrolytic capacitors, and a heavy-duty bridge rectifier.


----------



## ignator (Dec 3, 2018)

Entropy455 said:


> The typical weak link in the design (the reason for derating) is the DC ripple, and not necessarily the diodes. More specifically, the capacitor bank is too small to filter a single-phase ripple. I might be able to simply jumper in extra capacitance, and use the stock rectifying diodes - depending on the VFD unit I select.


As I've indicated before, my large lathe has a 7.5HP motor, with a 10HP VFD. I've never tripped it from DC bus voltage fault cause from excess DC ripple. I've done a turning cut in low carbon steel 0.5 inch depth, with a .004" feed per turn. No problems. The same can't be said with my small lathe with a 1HP motor where I can overload it easy.
I do believe you are overrating your real 40HP needs. With a VFD, if you over do it, it just shuts down, and the worse thing is damaged carbide tooling.
I can only say from my past engineering days, when management would say "better is the enemy of good enough". Your making the full load 40HP capability requirement, beyond any possible use.

So I asked the Aliexpress seller about the manual earlier in the afternoon, and just received 8 PDF files for the drive. You can set the drive up for vector or V/f control.  Also the DC bus has terminals for external power, if you still want to go that route.

I'm guessing you want to go with TECO name brand. Curious what their price is for a rated drive.


----------



## ignator (Dec 3, 2018)

Entropy, if you are still considering the import drive, I would go the eBay route because if there are any issues, you have their and PayPal protection.
A quick look at the manual, I'm impressed by the readable text. Only issue I see is chapter 1 page 4-5 with Chinese page numbers.
I'm confused by chapter 1 page 12  general precautions, about converting to 2 phase input. That can be a real thing with a Scott T connection. So I don't think they implied this to be single phase. But ?.
I don't see anywhere in the manual that this large of a drive is supported by single phase input. Chapter 2 page 15 has a table. Other locations indicate single phase for the 2.2KW and smaller.
Chapter 7, Table 7-1 page 228 does not seem to have model V8-G 2S 30R0G listed. So I assume the single phase models are not in this manual. There may not be a custom manual in English for this model number.


----------



## Entropy455 (Dec 4, 2018)

I'm not stuck on any particular brand. I called Teco simply because their number was easy to find.

The e-bay seller sent me the manual also. The fact that the model number is not contained within is problematic. The capacitor bank required for single-phase 40 HP operation is gigantic (more than double a 3-phae unit). I'm not sure everything required for single-phase would fit inside that box. . . .

And what the heck is 2-phase? There is no such thing - unless they are describing a center-tap transformer - which is technically 180 degrees out. . . I guess. . . . I want to purchase the V8-G 2S 30R0G model, but my gut is telling me this is really a 40 HP 3-phase unit. There is some shade-tree advertising going on. Every performance variable is clearly specified, yet the input power is implied.. . . .

Teco said I could probably get away with running a 75 horsepower VFD on single-phase, without any modifications - pointing out that I will rarely (if ever) push the motor beyond 30 HP - which I agree, is likely a fact. . . .


----------



## ignator (Dec 4, 2018)

From seeing the quality of the manual, I think this China manufacture probably got its start manufacturing namebrand USA/EU products. And they have the intellectual property transferred to them to make products of their own (copied) design.

I'm curious what the input power is to a 40HP motor with no load. That probably is 70% of the power you will ever supply to the machine, as the cutting power needed will in my mind always be small in comparison. A quick search finds no load current to be 30-40% of max load. It has been a long time since my engr'ing school on AC machines, and from memory the only useful thing I learned was about a RPC, the subject of this thread.

I messaged back the Aliexpress seller to see if they can provide model number specific data to show this model was designed to support single phase input. If I get any useful reply I'll post this here.

From the manual provided, table 7-2 is missing any VFD box size data for models 11Kw and larger. Makes me wonder how much of this manual is plagiarized from namebrand products. 
Someone took the time to make the artwork diagram showing this VFD powered from single phase. I can't imagine that is a 'shade-tree' seller, as they typically have no technical knowledge for this. This model does appear to be labeled a phase converter (found at different web sites), that just happens to be a VFD.


----------



## ignator (Dec 4, 2018)

This was what I got from the Aliexpress seller;
*Hi, thank you for your information.

The model V8-G 2S 30R0G. 
220VAC, single phase 40HP 30KW is the customized VFD. It's NOT the standard VFD .The manual is just for the standard VFD . But it's the same to set parameters .

please understand.*


----------



## Entropy455 (Dec 5, 2018)

*Hi, this model is NOT standard VFD, we need customize it . But the manual is only for standard VFD .*

Above is what I just got from the e-bay seller.

I understand the language barrier. Nonetheless, they need to be able to answer a simple question, like "will this VFD power a 40 HP motor with 220 volt single phase input power, or must the unit be de-rated operating on single-phase power?" If they are smart enough to modify the unit for 40 HP @ single phase input, then they "should" be smart enough to tell me so - when asked directly. . . .

The cryptic answers are frustrating. The internet is loaded with complaints about other Chinese manufactured VFDs that fail to perform on single-phase, as advertised (requiring derating). I don't want to make that same mistake.. . .


----------



## ignator (Dec 5, 2018)

Unfortunately, your not talking to the manufacture, but a sales clerk. They have no technical knowledge.
I have one of those Hungwang VFDs I purchased from eBay 5 years ago. They had to replace the first one. The problem with them is they cheapened the quality of the components, mainly the capacitors, as that was the failure I experienced, and what I see from the various negative complaints. I think I paid $115, and it sits on the shelf, as I got a used namebrand for the same price. I have 8 machines now powered with VFDs (all dedicated to each machine). Most are TECO, but two Hitachi, one WEG. I do not purchased used VFDs, unless I can find the manual online, and get a pdf copy. Rockwell automation (was Allen Bradly) is one such brand I've never found manuals for.

I believe they (Vantrend) have made a model that is capable of single phase input. The AliExpress and eBay pages do not have any dimensions for the unit. The size of the 3 phase input unit vs this one "custom" designed for single phase input would be a deciding comparison, as you've found the filter is huge.

I know that I would trust this machine to do what the sellers are showing it was designed for. I would purchase through eBay and connected it immediately and verify operation of the lathe, so if there is failure, you have eBay's money back guarantee. 
If you can get the dimensions and validate in your mind this has the filter size needed for single phase operation, that may give the "warm fuzzy". 
So I looked up eBays "not as described" return policy, and found this;
_A buyer must request a return no later than 30 days after the actual (or latest estimated) delivery date, or, if the seller's return window is longer, within the return window_
_The cost of return shipping for an item that is not as described is the seller's responsibility, _same is true for any custom duty or other fees.

So you have 30 days of test time from date of receipt to complaint through eBay's system. I've never failed to get a refund when their system is used. I've purchased many items from China, I've learned the only items not to buy are HSS endmills. I never received, any endmill that passed my rockwell hardness test. They are all soft as butter (HSS=Rc >64, non were harder then 25, some less then 4, but I bought cheap, don't even try it if SWT brand). I tried to get metric size endmills, still don't have any. I've had good luck with ceramic tooling, boring bars both indexed and brazed, R8 spindle tooling has been good.
Do you have any tooling and large scrap to turn and face and prove the converter will perform to your satisfaction? Your only out your time if this fails early and purchased from eBay.


----------



## Wizard69 (Dec 5, 2018)

Guys, one of the bigger factors in successfulrunning of a VFD on single phase is the size of the input rectifier.  Obviously single phase currents are much higher for a given amount of motor power so the rectifier needs to be able to handle this extra current.  

This is where talking to an applications engineer can save you a lot of grief.  They have access to the documentation that details the component size.  The topology of VFD’s is largely the same from manufacture to manufacture for low end drives.  That is the AC input is converted to DC via a rectifier and filter.   That DC voltage is thenfeed to the rest of the drive for conversion to AC.  That input section needs to be robust enough to be reliable and maintain that DC bus voltage.


----------



## Entropy455 (Dec 5, 2018)

If I ever buy a new place, it will have 3-phase power in the shop. . . .


----------



## mcostello (Dec 6, 2018)

I have a small home based machine shop. Usual equipment. 20-30 years ago 3 phase power was about 2 miles away and the cost was around $2000 to get it here. Now They have put in new lines with 3 phase power to balance the load. It is along the road 150' from the shop. I asked the cost expecting to make the change now that it is close. More than $2000 with a commercial account to go with it. Think I'll keep what I've got.


----------



## Entropy455 (Dec 6, 2018)

If 3-phase were running along my property line, the decision to bring it into my shop would be instantaneous.  The problem is that the 3 phase power is 2 miles from my house. About half that run would require adding the second feeder-wires to the telephone pole(s). The last mile however is where the cost balloons out-of-control. Power lines in my neighborhood are required to be underground. The underground wire (7200 volt coaxial direct-burry) is 12 dollars per foot (I'd need two wires) - that's 125 grand just to purchase the last mile of wire. I have no idea how much the above ground portion would cost, or the cost of the 3-phase transformer. I pretty much gave up at 125 grand. . . . .

When I built my shop, my property had a single 200 amp service (to the house). I had the service upgraded to 320 amperes, with a 185 foot run of 350 x 350 KCML x 4-0 feeder wires - which will support a 200 amp panel on the house, and a 200 amp panel on the garage. The bill from the power company for the upgrade was just under 700 dollars. That was with me digging the ditch, purchasing & installing the panels, and also purchasing & installing the below-grade conduit (required for low-voltage feeders).


----------



## ignator (Dec 7, 2018)

Entropy455 said:


> When I built my shop, my property had a single 200 amp service (to the house). I had the service upgraded to 320 amperes, with a 185 foot run of 350 x 350 KCML x 4-0 feeder wires - which will support a 200 amp panel on the house, and a 200 amp panel on the garage. The bill from the power company for the upgrade was just under 700 dollars. That was with me digging the ditch, purchasing & installing the panels, and also purchasing & installing the below-grade conduit (required for low-voltage feeders).


"You bloom where you're planted", looks like you built a superduty large shop, and did everything for the machine shop power. 
I'm guessing your back to 'plan A' of building your own RPC. Sorry for the divergent path.


----------



## Entropy455 (Dec 8, 2018)

There is more than just cost at play here. I purchased a 1.5 horsepower VDF & motor kit from dealerselectric - for my little lathe (1800 rpm fully enclosed motor, constant-torque 230 volt VFD). I'm going to install this unit, and see how much I like it.​
My goal was to keep the 80 horsepower rotary phase converter project below $2500 (which includes the cost of bringing in the additional 200 ampere panel to assist powering it). The problem is that the contactors cost five times more than anticipated. By the time I'm ready to push the start button on my phase converter (with all the hidden costs), I'll probably be within a grand of a VFD.

If I purchase a VFD for my large lathe, it will be this one: https://dealerselectric.com/EQ7-2125-C-SRPLS.asp     I'm not happy about the cost, but it's the proper size for my machine. The units cost what they cost. . . ..


----------



## ignator (Dec 8, 2018)

I think I mentioned that I purchased many VFDs from Dealers Electric.  Fast delivery, and seems to be the best price that I've found.
Also I wrote in many threads the ability to have a conversion constant to display spindle RPM, as I find I never need to change the belts on the small lathe (or drill press, milling machine). The motor is a 1800RPM model, and I set the max Hz to 120 which gives a very wide speed range. It is just very handy setting the spindle RPM directly.

I started with a V/f model on the lathe (TECO flux master 100), and it 'cogged' at low RPMs, so just last year put a Hitachi that I picked up NOS from eBay for <$80, this is a sensorless vector drive.
The big lathe I run at 60Hz and use the gear head speeds. However when threading I typically slow it way down.
I recall somewhere in this thread your mid size lathe came with a VFD, but that may be some other thread I'm recalling.

That 100Hp unit is $. They have a soft charge circuit, so the surge current during power on is reduced. I see the spec sheet indicates single phase operation for your power of motor. 
Apology's if I'm repeating myself from short term memory.

Back to the project of installing solstice lights.


----------



## Racene (Dec 8, 2018)

I'm constantly amazed that everyone is hooked on VFD's  in my  opinion not worth the money (into someone else's pocket ) or  effort,take a look at the DC option using 4 -5 hp tread mill motors,results are surprising and cheap,motors can be sourced from local verge side collections for free or purchased very cheaply from the distributors (of fitness equipment treadmills)you don't need to use the TMs electronics if you don't want too as everything to get you running is availible off  flea bay,look up  You Tube under  DC Treadmill motor for machine tool application ,Lathe ,milling machine, drilling machine ,
every AC powered machine tool in my shop has been converted to DC treadmill power,lathe ,mill ,table saw,bore pump,thicknesser to name a few,look into it an save $$$$$$'s.  all vairable speed  controlled and another bonus no loss of power from high speed to low or vickey versea


----------



## Entropy455 (Dec 8, 2018)

Standard DC motor voltages are 90 volts, and 180 volts. The majority of off-the-shelf DC motor controllers are the same. Treadmill motor voltages however are normally anything but standard (voltage ratings vary widely between manufacturers). This is why surplus treadmill motors are dirt cheap - because standard controllers won't work. If the treadmill's controller is integral to the display, then your lathe will display in mph. That's ok, I guess. The biggest problem is that they turn freakishly fast (between 4000 and 7000 rpm), and have very heavy flywheels attached. It's the only way to get the required inertia/momentum to dampen out the impulse events of a heavy human foot jamming into the belt.

Consider that I just purchased a 1.5 horsepower 1800 rpm totally enclosed VFD rated motor, with a constant-torque VFD controller (a package deal), for less than 300 bucks. It's practically a bolt-in within my little lathe. Whereas a 7000 rpm treadmill motor would require custom mounts, a flywheel guard, with an additional jackshaft to slow the input speed way down. The headache is simply not worth it - even if the treadmill were free. . . . (just my opinion). A standard industrial 1.5 horsepower DC motor with PWM controller would easily cost between 600 and 900 dollars.

My large lathe is 25,000 pounds, with a 40 horsepower drive motor (the problem at hand. . . .)


----------



## Entropy455 (Dec 9, 2018)

Rotational power is equal to torque times angular velocity.

DC motors have constant torque, therefore there's very appreciable loss-of-power at lower rpm. The DC motor rpm is also heavily dependent on shaft load. The main advantage of DC motors is that they make torque over a wide rpm range, in lieu of simply stalling out (like AC motors).

However enter the modern VFD - where AC induction motors may operate over a wide rpm range, at a constant torque - with the fantastic advantage of stable shaft speeds with varying loads. Plus no brushes to replace, and no carbon dust to clean between windings. In many ways, VFDs are vastly superior to DC drives.


----------



## DJP (Dec 9, 2018)

I have been following this discussion with interest and after debugging the variable speed controller of a mini-mill with DC motor I have come to the conclusion that simple is better. A 3 step pulley and belt works well enough for my needs and as for the mini-mill I directly connected leads to the motor to supply 90 VDC in the event that the speed controller failed during an important job that I needed to finish. Luckily I found a few poor solder joints and a defective (not too robust) speed control pot to make the mill run again. For my Bridgeport I have a single phase 240VAC motor and it also suits my needs.

For hobby use I like simple machines although 3D printing needs some investigation.​


----------



## ignator (Dec 10, 2018)

DJP said:


> I have been following this discussion with interest and after debugging the variable speed controller of a mini-mill with DC motor I have come to the conclusion that simple is better. A 3 step pulley and belt works well enough for my needs and as for the mini-mill I directly connected leads to the motor to supply 90 VDC in the event that the speed controller failed during an important job that I needed to finish. Luckily I found a few poor solder joints and a defective (not too robust) speed control pot to make the mill run again. For my Bridgeport I have a single phase 240VAC motor and it also suits my needs.
> 
> For hobby use I like simple machines although 3D printing needs some investigation.​


I think you missed the point of this thread. The OP has a large industrial lathe (HUGE to be more accurate), which dwarfs all hobby machines. It has a 3 phase 40HP motor. There is no simple solution to power this in a home shop with single phase power.
I do want to correct your assertion that VFD's are complex. They are commodity machines these days, and very affordable. 40 years ago, they were just coming to the HVAC market for fan speed control. Now VFDs are in home washing machines, and air conditioning systems. 
Simple is plugging a lathe or mill into a wall outlet as purchased from the tool dealer. Wiring a VFD does take the ability to connect "door bell circuits", as making cords and wire interconnect that operate at AC line voltages and currents takes some domain knowledge to do safely. From reading comments about hobby machinists purchasing industrial equipment, there is this fear of buying a 3 phase machine, as they now must add additional wiring and systems that generate 3 phase, and that may push them into an area where they lack the knowledge. The cost of a rotary phase converter (RPC), purchased off the shelf is moderately expensive. There are many posts about making RPC's home-made. There are many posts about connecting a VFD to a 3 phase motor. If you price a VFD vs RPC, the cost difference is nominally 3:1 less expensive (in the 3HP, 4.5Kw size). There are very cheap VFDs of the Hungyang variety that currently are not reliable (that will change, but gives a bad name to VFDs, and hobbyists have found these $110 USD solutions attractive). Most namebrand VFDs are manufactured in Asia, from quality designs.
Changing a motor to DC and connecting a speed controller is just as "complex" as connecting a VFD. Both give variable speed. If the motor comes from a treadmill, that takes additional skill to make a motor mount as well the skill to hack the electronics.
When I see machine shop equipment sold locally, the 3 phase machines are less expensive over single phase. We all are cost sensitive in this hobby, and passing on a machine because of a perceived "complex" power system needs to be understood by those in the market for shop equipment. If a hobbyist does not have the skill to connect a VFD or RPC, they should stay away from 3 phase machines. But that is a small count of hobbyist's that grew up fixing and manufacturing repair parts, as they also repaired electrical appliances, and learned how to work with AC power. 

All that said, my Wells-Index vertical milling machine has a 1960s 3 phase motor. NEMA changed the motor dimensions since this machine was made. That and it has a bastard C-face motor. It would be a major effort to convert to single phase. Originally, I powered it with a home built RPC. This worked but I always had to manually start it, and it was noisy in the shop. I found a very affordable VFD, and I would never go back to fixed frequency operation, as I now can control spindle RPM directly from the VFD display. It makes switching between using an edge finder, drills, boring head, quick and I can convert the SFM to spindle RPM, and dial in the speed to not damage my tooling or the part.


----------



## DJP (Dec 11, 2018)

My comments were not about the discussion to power a very large lathe in a non-industrial infrastructure. I was only saying that any additional complexity is a potential new failure point which is why I prefer simple motor/belt/pulley driven machines for my hobby use. 

Your example of washing machines with VFDs also doesn't sit well with me. My wife and I had a Maytag washer that dutifully cleaned clothes for over 40 years. It was purely mechanical. Our daughter is now on her third modern front loading washer with fancy circuit board. When the board fails the machine is scrap and needs to be replaced. I'm not sure what fails but the added convenience drives complexity and the cost to repair is too high. We bought a new commercial duty washer recently (a clone of our old washer) and expect it to last beyond our lifetime.

Thanks for the historical overview of creating 3 phase power. Your response is a valuable addition to the forum.


----------



## ignator (Dec 11, 2018)

DJP said:


> our example of washing machines with VFDs also doesn't sit well with me. My wife and I had a Maytag washer that dutifully cleaned clothes for over 40 years. It was purely mechanical. Our daughter is now on her third modern front loading washer with fancy circuit board. When the board fails the machine is scrap and needs to be replaced. I'm not sure what fails but the added convenience drives complexity and the cost to repair is too high. We bought a new commercial duty washer recently (a clone of our old washer) and expect it to last beyond our lifetime.


Agree 100%, my Maytag that came with the house (1972 manufacture) failed from the timer motor (that drives the drum switch) plastic gears, that became embrittled, replaced in 2002. I glued them back together only to have it fail completely.
Front load washers are nothing but a short lived machine. The circuit boards are not of commercial quality, nor is the valued engineered design. Components are not derated (2x thermal overage), and hence overheat. They do what the industry wants, have you replace them every 7 years.

Industrial VFDs are a different class of machine. But eventually they will fail. Most likely the micro processor or the memory, as the silicon technology is getting so small that the applied DC voltages cause metal migration, and this is where size matters in silicon integrated circuit design. Same issue with all PCs, although lately it's the OS that has caused me to buy new hardware. But that is why I shut my VFD off, when not used, as well lightning strikes are an issue in my mind.

I'm with you on complexity, in automobiles I was happy with electronic points, as that was the only issue I ever had with engine maintenance. Folks will say you need the electronics for high fuel efficiency, this is not true, I owned a 1987 Chevy Metro, one liter 3 cylinder. It got 54MPG with a carburetor.  And because it was 1400 lbs, was very peppy. But it would be a death machine from crash survivability, as it was #1 in that category, the #2 car was a heavy Buick, the difference was the age of the drivers (very young vs very old). The engine is a Suzuki design, as the early imports were rebadged Suzuki Justi models. In fairness, heavy autos need electronics for fuel burn reduction, but mainly for emission compliance. And that we are stuck with.


----------



## TSutrina (Dec 11, 2018)

ignator said:


> I think you missed the point of this thread. The OP has a large industrial lathe (HUGE to be more accurate), which dwarfs all hobby machines. It has a 3 phase 40HP motor. There is no simple solution to power this in a home shop with single phase power.
> I do want to correct your assertion that VFD's are complex. They are commodity machines these days, and very affordable. 40 years ago, they were just coming to the HVAC market for fan speed control. Now VFDs are in home washing machines, and air conditioning systems.
> Simple is plugging a lathe or mill into a wall outlet as purchased from the tool dealer. Wiring a VFD does take the ability to connect "door bell circuits", as making cords and wire interconnect that operate at AC line voltages and currents takes some domain knowledge to do safely. From reading comments about hobby machinists purchasing industrial equipment, there is this fear of buying a 3 phase machine, as they now must add additional wiring and systems that generate 3 phase, and that may push them into an area where they lack the knowledge. The cost of a rotary phase converter (RPC), purchased off the shelf is moderately expensive. There are many posts about making RPC's home-made. There are many posts about connecting a VFD to a 3 phase motor. If you price a VFD vs RPC, the cost difference is nominally 3:1 less expensive (in the 3HP, 4.5Kw size). There are very cheap VFDs of the Hungyang variety that currently are not reliable (that will change, but gives a bad name to VFDs, and hobbyists have found these $110 USD solutions attractive). Most namebrand VFDs are manufactured in Asia, from quality designs.
> Changing a motor to DC and connecting a speed controller is just as "complex" as connecting a VFD. Both give variable speed. If the motor comes from a treadmill, that takes additional skill to make a motor mount as well the skill to hack the electronics.
> ...




VFD creates three phases at the specified frequency.   They are designed to connect to three phase induction motors.  The output from a VFD is not a good sine wave.  Pulse width modulation in effect creates and average sine current into the motor winding.  The iron winding of the motor clean up the input to produces a reasonable good torque and motor speed.  However, there is a significant amount of heat created.  This is the reason that an induction motor for VFD are larger.  Basically to deal with the problem you need to derate the motor to a lower power and this is done by lowering the voltage or limiting the current or both.  I am a mechanical engineer that worked on the packaging of the electronics for  aircraft 400Hz AC power and a few motor drives for induction aircraft 3 phase motors.     The problem you may have if you can not get a VFD with sufficient power and  want to run the machine as a much lower power level is adjusting the drive to match the winding of the motor.  Basically the resistance of the winding is fixed, (may have more then one voltage capacity).  The VFD has a maximum current it can put out and you do not want to in effect connect it to a winding that is in effect a short circuit to the VFD.   It will go into current limit mode or put out to much current and fail.  So the voltage needs to be set lower and how to do needs to be discussed with the VFD manufacture.


----------



## ignator (Dec 11, 2018)

TSutrina said:


> However, there is a significant amount of heat created. This is the reason that an induction motor for VFD are larger.


I have never seen this issue with any VFD powering a 60Hz induction motor. Nor have I seen any mention of this in the VFD user manual. The frequency of a VFD is a square wave driven with a carrier frequency that is a programmable parameter of the VFD. Mainly you change this for noise suppression. True it is not a pure sine wave, but since it has a fast edge, the inductance of the motor limits the current. And the average of these pulses follows a sine wave in nature. Typical carrier frequencies of 3-15Khz, but it depends on the design and IGBT transistors used.
The bigger worry with a VFD is because V=L di/dt, the Voltage spikes can be big enough to punch through the enamel winding insulation. VFDs today control the dt edge rate to prevent this from being an issue. The issue if seen is from very old motors where the insulation is deteriorating or insufficient for the transients.

VFDs will reduce the voltage as the Hz is reduced per the V/f program which is a user settable curve.

Do note that the original OP has no desire to use an underpowered design solution for the lathe's 40HP motor. Because VFDs are using fast edge pulses, they soft start a motor without a large surge current of LRA. The OP also understands the rectifier and capacitor filters are overrated when powering the VFD from single phase input power. Eric's last posts indicated using a 100HP VFD that supports single phase input power, and this will power a 40HP motor.


----------



## Entropy455 (Dec 11, 2018)

Modern HE cloths washers are complete garbage (I finally purchased one when my old washer failed). The washer tub would only fill about 6" deep with water, where some cloths were literally out of the water. The agitator moved about as fast as someone turning to get up out of their chair. It took 90 minutes to wash cloths, and they came out dirty. I assumed the unit was defective, so I took it back, and purchased anther brand. It did the same thing - a complete garbage waste of time.

So I found a lightly-used 1980s vintage Maytag in the classifieds for 250 bucks, purchased it, and now I can actually wash cloths again. I gave the HE unit away.

Commercial washing machines are quite literally the only new machines out there that will properly soak & agitate (aka wash) your cloths. Avoid anything and everything new that says HE.

Below is my current big cannon. (this is the largest gun Americans may own without a permit). I only fire it on the 4th of July, to celebrate the 4th of July. It weighs about 2000 pounds, and is road towable. It will rattle windows over a one-mile radius, and you can feel the impulse solidly on your chest for a good 1/4 mile (it's lots of fun to shoot - firing blanks only for safety I might add). I need to get my big lathe running, because I want to turn a properly shaped cannon (aka hourglass traditional-looking) from some 20" diameter solid round bar.


----------



## ignator (Dec 12, 2018)

Entropy455 said:


> I need to get my big lathe running, because I want to turn a properly shaped cannon (aka hourglass traditional-looking) from some 20" diameter solid round bar.


So there is 'madness' behind owning your big lathe. It does look like fun.


----------



## ignator (Dec 12, 2018)

Entropy455 said:


> The washer tub would only fill about 6" deep with water, where some cloths were literally out of the water.


I ended up with a top load HE washer, I do not understand the water fill algorithm used, it alternates between turning on water, then swishing the agitator. And some unknown sensor data it uses to determine if the cloths are in deep enough. The lid safety switch prevents watching what it is doing. It's only been in use for a year. I stayed away from front loads for the reason of excess complexity. As well the many complaints of 'organic smells' from bio-degrading soap water. I don't see any conformal coating on boards that are operating in a damp environment. The matching dryer, is gas, I opened it up to install the LPG pilot and valve changes. I don't think there is anything of quality left from seeing how minimal every part is. I should say that it is fantastic value engineering, to take every ounce of quality to ensure an operation life just long enough to live through the warrantee period.
Maytag used to be made here in Iowa, they closed the plant over 15 years ago. The company morphed with Admiral, and now Amana, the only thing I see that is still of their design is the clips (under the top lid) used to access the machine for maintenance. My parents had a Maytag washer and dryer set that lasted 25 years of use, and used for 4 loads a day as it washed for 10 (I'm 2 of 8 off spring).


----------



## DJP (Dec 12, 2018)

The Speed  Queen Commercial brand seems to be of the same rugged design as the old Maytags. We bet our future washing needs on Speed Queen although rebuilding the Maytag with a worn internal bearing was an option. 
This post may not make sense in a forum about metal machining but it explains my philosophy of keeping my hobby lathe and mill as simple as originally designed. Rugged is good and my first Southbend lathe was well over 75 years old when I passed it along to another hobbyist and upgraded to a Myford S7.


----------



## Entropy455 (Feb 5, 2019)

Update:

I just picked up some 1600 amp contactors (three off them) - 200 bucks for the set (surplus). This means I'm back to the phase converter project.

I'm into the electric motors 600 bucks, and 200 into the contactors. Now I need about 400 dollars worth of capacitors. Then figure about another 300 bucks for miscellaneous supplies (terminals, lugs, indicators, paint, etc). I've already got the wire, a cabinet, and steel to make the frame for mounting the motors (all purchased surplus). Thus my 80 horsepower converter will end up costing about 1500 bucks.

Additional hidden costs - I need to install a second 200 amp panel in my shop. Figure 600 bucks more (for the panel, meter disco/reco fees, the conduit, feeder wires, etc).

The VFD would've been cool, but I'm saving 4 grand going with a rotary phase converter. The converter's idle-current will cost me about 66 cents per hour. The capacitors I'm purchasing are rated for 60,000 hours.


----------



## ignator (Feb 5, 2019)

Entropy455 said:


> Update:
> 
> I just picked up some 1600 amp contactors (three off them) - 200 bucks for the set (surplus). This means I'm back to the phase converter project.


Sorry I introduced a diversion.


----------



## Entropy455 (Feb 5, 2019)

No apology necessary.

As a result of your recommendations, I purchased a 1.5 horsepower 3-phase motor & VFD for my little lathe (super excited about it). I'm also going to retrofit my drill press with 3-phase motor & VFD.

If anything, I should be thanking you for turning me on to VFDs. . .

The decision to run a rotary phase converter for my big lathe is simply a function of cost. The contactors I stumbled on are several grand each, new. . . .

I also have plans to build a distributor test stand, using a 3-phase motor with VFD.


----------



## Wizard69 (Feb 7, 2019)

Entropy

Lots of luck with the rotary phase converter build!

As for some of the comments from various people about VFD's, I suspect many are misinformed about their reliability.   We literally have hundreds of them at work on various 3 phase and single phase installations and for the most part the electronic out last the mechanics they are connected to by many years.    The early VFD's where somewhat maintenance intensive, my early years included a lot of PTI drive repairs, but the modern highly integrated drive is a marvel of reliability.   I just wanted to set the record straight here.


----------



## ignator (Feb 7, 2019)

Entropy455 said:


> No apology necessary.
> 
> As a result of your recommendations, I purchased a 1.5 horsepower 3-phase motor & VFD for my little lathe (super excited about it). I'm also going to retrofit my drill press with 3-phase motor & VFD.
> 
> ...


Have you figured out the air pressure operation of the lathe, as this was your original post question.


----------



## ignator (Oct 6, 2019)

Entropy455 said:


> No apology necessary.
> 
> As a result of your recommendations, I purchased a 1.5 horsepower 3-phase motor & VFD for my little lathe (super excited about it). I'm also going to retrofit my drill press with 3-phase motor & VFD.
> 
> ...


Entropy455, I was hoping you would update this thread with a working 40HP RPC, and photos of the canon newly made. I assume the VFD install went well with your "baby" lathe.


----------



## mcostello (Oct 6, 2019)

I think I have missed Him starting His lathe up as I did not see My lights getting dim.


----------

