# VFD Wiring



## Gordon (Nov 13, 2018)

I decided to give a VFD a try on my lathe so I ordered a VFD and I am unsure about the wiring. I understand the basic power in and power out and operation from the built in control panel. My question is on the wiring of external control. I am thinking a forward, reverse and stop button. Also a remote speed adjustment rheostat. The diagram shows input points for this but I am not clear on whether the existing panel mounted buttons must be disabled of if both can be used. Also are the remote buttons momentary or maintained? It would seem like the existing speed control would have to be disabled in order to use the remote. I will perhaps also want to look at some of the other settings like ramp up speed and brakeing but that will come after I get the basic equipment running. I will perhaps want to do some tapping etc which would require low speed but fairly high torque.

Input is welcome. Many of the terms used in the instruction sheet are terms I am not familiar with.

Gordon


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## miglincit (Nov 13, 2018)

Your questions rely on the type of VFD you are going to use - so it would be a support to any answer if you share this meaningful information with us.
E.g. I am using an Omron MX2 VFD. And  I have to set certain parameters to achieve the behavior you described (and which fits to my application as well).

Thomas


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## Gordon (Nov 13, 2018)

Sorry. I was going to included that information and got sidetracked and forgot to go back.
It is a Huyanyang model HY01d523B.  It appears that this is sold under several different names and brands but they all seem to be the same thing.


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## miglincit (Nov 13, 2018)

Haven't you got a manual with it ?
I found one here: https://www.exoror.com/datasheet/VFD.pdf and on page 16 (chapter 3. Basic Connection Diagramm) you can fine the information you were looking for:






it seems that the functions you would like to have are already set as factory default - the buttons have to be momentary one, or else you would have to have them mechanical  released against each other.
Carefully chose the cables and the shielding!

Thomas


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## Gordon (Nov 13, 2018)

OK Thanks. I have that. My question was mainly whether the contacts would be momentary and if the existing panel controls have to be disabled. I understand the start stop buttons but I still wonder about the variable resistor. It would seem that you could not have two resistors in the circuit at the same time. Just do not want to plug it in and see fire and smoke. I do not have anything wired yet at this time. I had another VFD on this lathe several years ago and took it off because I could not get enough torque to actually run the lathe under load. It was a very used control so I assumed that it was probably defective. Prior to that I had a large unit with three phase in and that worked great until I sold my business and moved the lathe into my home shop. I have been operating on a phase converter but wanted the variable speed so I thought that I would try this.


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## XD351 (Nov 13, 2018)

I think you will find that you will have to set the programme PD 001  to 001 ( its default is 000 which is the digital operator Or onboard front panel ) 001 is external operation via multi access ports which will be for, rev ,sph, spm, spl rst and dcm  and vr , vl acm and al.


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## Blogwitch (Nov 13, 2018)

I have had most of my wiring sorted for the Siemens Micromaster VFD and pendant that is going to be fitted to my lathe.

Basically, once you put the 3 ph motor on the lathe, all wiring originally used for the 1ph that is on your machine becomes redundant. The motor is totally controlled from the pendant.
What I am going to do is take the pendant wiring and it's switches from the VFD and fit them into the holes in the front of my lathe (I have already bought the correct sized switches and pots to fit the holes). My only problem is working out how the spindle manual footbrake will need to be wired in and whether the VFD minds about having an instant stop spindle.
Time to read the manual a little more.

John


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## joco-nz (Nov 13, 2018)

Gordon,

Given you are using this on a lathe also think about  a braking resistor, unless of course you plan to use unbraked stopping of the spindle. 

The input terminals are usually pretty configurable and can be setup for different functions, not just the default set per the diagram posted. I have chinese VFD on my mill.  For example it can be setup to use momentary or latching buttons, use different functions than the defaults set, even control the speed using a 3 bit register to access a speed (frequency) table you configure in the software. 

Have fun with the new toy.   Now i have a VFD on a mill I wouldn’t go back. 

Cheers,
J.


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## MachineTom (Nov 13, 2018)

I've done a few VFDs, the setup is a 220V line running 4 machines, controlled by a single knife switch. That is used to turn on power to all machines. Each vfd has a square D push/pull maintained switch. call this an enable switch, theses are connected to the low voltage terminals, the forward/rev is a square d 2 position double contact twist switch. This wired in series with the enable P/P switch, by doing that the Enable switch has to be on for a direction to be chosen. 
Set as described both switches use maintained operators. They are not cheap, and can be replaced with toggle switches at much less cost, one being on/off single throw, and the other being an on/on single throw. Wired so the feed comes first to the enable switch, one lead back to the enable post of the low voltage terminal, a second wire to the common of the on/on switch, then leads to the fwd/rev posts of the terminal block.

you will have to chose each of the parameters the enables all theses function. The speed control is 3 wires, 10K wire wound pot. Again you need to assign the parameters to enable the remote pot. 

The current control panel will only be used for programing, no hand in operation.

PM if you need assistance.


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## sgunsel (Nov 14, 2018)

MachineTom said:


> I've done a few VFDs, the setup is a 220V line running 4 machines, controlled by a single knife switch. That is used to turn on power to all machines. Each vfd has a square D push/pull maintained switch. call this an enable switch, theses are connected to the low voltage terminals, the forward/rev is a square d 2 position double contact twist switch. This wired in series with the enable P/P switch, by doing that the Enable switch has to be on for a direction to be chosen.
> Set as described both switches use maintained operators. They are not cheap, and can be replaced with toggle switches at much less cost, one being on/off single throw, and the other being an on/on single throw. Wired so the feed comes first to the enable switch, one lead back to the enable post of the low voltage terminal, a second wire to the common of the on/on switch, then leads to the fwd/rev posts of the terminal block.
> 
> you will have to chose each of the parameters the enables all theses function. The speed control is 3 wires, 10K wire wound pot. Again you need to assign the parameters to enable the remote pot.
> ...



Using the vfd to force a stop can be problematic. It will definitely stop the motor quickly, but that can cause threaded chuck to unthread or other locking/securing arrangements to fail. Be careful.


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## Canobi (Nov 14, 2018)

I can vouch for screw on chucks coming off with sudden stops, exactly that happened to me when I first installed my VFD.

Scariest thing that ever happened to me on my lathe since I've had it but luckily I wasn't hurt. It was a close call though, so I now have the ramp to stop time set to about 2 seconds so stopping is a bit gentler.

I installed a brake resistor but as far as I can tell, it's never been used yet, possibly as my lathe is only a 3.1/2" x 24" and I don't turn large stock very often but it's there if ever needed.

I've yet to actually implement taking advantage of the manual input controls on my VFD, though I have a complete system worked out using momentary and latching pushbuttons that will essentially automate the carriage for screw cutting.

If you interested, I documented my install and future plans for the VFD over at Homemade tool.net:

http://www.homemadetools.net/forum/new-lathe-electicals-subsequent-bench-mods-hint-restoration-63777


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## MachineTom (Nov 14, 2018)

When you setup the vfd, the acceleration on start time will default to be used as a Decceration time on shut off. There is little need for instant stop. 

I once blew the braking diodes on a vfd, with a heavy load in the biggest chuck, due to  shifting out of backgear, without reducing the speed control. As a 40lb chuck with an 80lbs workpiece past the 2000rpm point on its way to 3000rpm, I shut off the control, which went into braking mode. The resistor I had at the time could not handle that much current, high voltage blew the brake diodes. I now have the correct size braking resistor on that machine.
The VFD still works just no braking, so I mounted on the milling machine.


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## ignator (Nov 14, 2018)

Gordon;
I recommend PD026 set for coast to stop. If your lathe has a foot brake, you don't want the VFD to drive it to stop, as well, you need a signal from this to send a stop to the VFD (I didn't see any post about the lathe). It also negates any reason to mess with braking resistors.
You indicated torque problems, depending on how slow Hz you run the drive, and torque requirement, you may find this VFD to be the same as your first experience. I started with TECO FM100 VFDs on a 1HP motor, both my drill press and lathe. It would cog at low RPMs, and would stall out with nominal cutting. I ended up replacing the drives with sensorless vector drives, which could develop torque down at 1 Hz operation, and smooth turning of the motor shaft. Both these machines are belt drive, and I leave the speed reduction of the belts to the middle setting. The motors are nominal 1800RPM, so I set the max Hz of the VFD to 120Hz. This will let the motor spin up to 3600RPM, and the motor rotor is capable of this. With a constant belt reduction ratio, parameter PD144 can be changed so when the display is set up to show ROTT this will be your spindle RPM, which I find very handy when calculating SFM cutting speed.


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## cds4byu (Nov 14, 2018)

I'm working on a VFD setup for my Enco lathe which has a similar schematic diagram to most of the chinese lathes.  I also have an HY VFD like you reference.

I will be using the front controls to supply input power to the VFD.  I will also be using the forward/reverse handle on the lathe to provide control signals to the VFD.

I will move my thermal protection relay to the output of the VFD, and have the control signal from the TPR go to the input of the VFD, rather than opening up the main contactor as it currently does.

I have been sidetracked by other projects, so I haven't made my schematics yet.  I'll try to put together a sketch in the next couple of days and post it here.

Carl


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## Gordon (Nov 14, 2018)

I received the drive. I was looking at the downloaded manual before I got the drive. The manual which came with the drive is different than the downloaded one. I connected the input power and ran wires to the motor. Not sure if the unit is bad or I am just missing something. When it is plugged in the cooling fan runs for about 10 seconds and stops which may be correct. None of the panel buttons do anything. I suspect that the drive is DOA. I have contacted the seller.


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## XD351 (Nov 14, 2018)

E-stop may be active


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## Gordon (Nov 14, 2018)

No e stop button. Just input voltage and output leads to motor.


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## ignator (Nov 14, 2018)

Gordon said:


> I received the drive. I was looking at the downloaded manual before I got the drive. The manual which came with the drive is different than the downloaded one. I connected the input power and ran wires to the motor. Not sure if the unit is bad or I am just missing something. When it is plugged in the cooling fan runs for about 10 seconds and stops which may be correct. None of the panel buttons do anything. I suspect that the drive is DOA. I have contacted the seller.


If you can't get it into program mode, then it is DOA, do the LED digits show anything on power up?


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## tornitore45 (Nov 14, 2018)

I do not think the FW REV button are meant to be pushbuttons.
A 3 position switch ON-OFF-ON takes care of FORWARD STOP REVERSE
Some VFD have options to redefine them as DIRECTION and ON/OFF the only temporary switch should be the Emergency Stop.


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## XD351 (Nov 14, 2018)

The E - stop is the reset pin on the schematic and may need to be tied to the dcm pin to clear the reset . On mine the fwd /rev is a centre off toggle switch  as tornitore45 mentioned .


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## Gordon (Nov 15, 2018)

There are no switches on the unit and I cannot get to a programming mode. When the unit is connected to input power the cooling fan starts and runs for about 10 seconds and the display shows 400 and none of the buttons do anything. I tried a  jumper for the for and rev but nothing happens.  I contacted the eBay seller and he has not responded. I have requested a return. I am about 99% sure that the unit is DOA.


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## ignator (Nov 15, 2018)

Gordon said:


> There are no switches on the unit and I cannot get to a programming mode. When the unit is connected to input power the cooling fan starts and runs for about 10 seconds and the display shows 400 and none of the buttons do anything. I tried a  jumper for the for and rev but nothing happens.  I contacted the eBay seller and he has not responded. I have requested a return. I am about 99% sure that the unit is DOA.


400 is not a error code, I suspect this is set for 400Hz, does rotating the speed knob change this value?
If none of the membrane keys do anything, I suspect you are correct in this being DOA.
I've purchased from this company many times, they have name brand drives;
https://dealerselectric.com/230V-si...id=28149&pgID=1&SortBy=PriceAsc&GdPageSize=20

The above link is for all drives of 2HP, from low to high costs.


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## ignator (Nov 15, 2018)

I see your drive does not have a speed pot attached. The 400 does not make sense as I'm pretty sure without a remote 3 wire potentiometer attached, it should command zero speed, not 400 Hz. But everything should be controllable from the membrane keyboard on a new unit, unless this was a used unit sent back to the seller and has parameters messed up.


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## Nick Hulme (Nov 15, 2018)

Buy based on quality and support, you'll actually be better off in the long run. I just had a Siemens Micromaster Vector VFD fail, it's about 20 years old and was ex-industrial when I bought it about 15 years ago, Siemens still offer all the documentation for it in good, clear, comprehensive detail in good clear English.


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## KellisRJ (Nov 16, 2018)

Not all VFD accept an external braking resistor. I'm  going to take the Siemens note under advisement as many manuals are written using as few words as possible and take a considerable ammount of back and forth cross referencing.  Keep notes in the back. Even though there are no controls on the face,  don't assume the VFD doesn't still need to be programmed for external control. 
On mine, all the buttons are NO momentary close except the stop that is NC. I have my stop wired through three series switches located in strategic places should others find they need to stop the machine.


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## ksor (Nov 17, 2018)

Hi there !

It's a hell og a job to configure such a VFD - I found out you get MUCH more understanding of what facilities it has if you read the manual - I think time reading is a good investment !

These days I'm alfa/beta-testing my change of motor and elektric installation on my old russian Stanko 1A616 from 1962.

More details here in danish but you can Google Translate to the right just under the menu line - choose whatever language you like in the combobox - within an hour there is a video showing my test setup and the schematic for the control box - take a look:

https://kelds.weebly.com/skifte-motor-paring-drejebaelignk.html


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## cds4byu (Nov 18, 2018)

cds4byu said:


> I'm working on a VFD setup for my Enco lathe which has a similar schematic diagram to most of the chinese lathes.  I also have an HY VFD like you reference.
> 
> 
> 
> ...



Here's my blog post that describes the wiring of my lathe.  The existing controls now work with the VFD.

https://13x40.blogspot.com/2018/11/adding-vfd-to-my-enco-13x40-lathe.html

HTH,

Carl


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## KellisRJ (Nov 19, 2018)

Gordon said:


> OK Thanks. I have that. My question was mainly whether the contacts would be momentary and if the existing panel controls have to be disabled.


 Gordon, the answer is in the lower left of the diagram Thomas posted. What it shows us that all the control functions are powered by the " DCM" lug to the normally open (NO) momentary closed switch (button) to the control lug shown .  The top one in the  diagram is forward. For the speed pot, the "AI" in my VFD is for digital input. The other 3 are for typically a 10 ohm "pot". I know pots have a standard configuration, but not knowing what it is I just used a multi-meter to figure them out. Hopefully yours isn't DOA or this will help with your next one. Learning about the buttons/switches was an education. The better ones are two separate things, allowing for guarded buttons on say the start or reverse. The switches are often duel NO/NC depending on which lugs you use. Get shielded wire, easy to find on eBay, just be sure to get the number of wires you need.


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## Gordon (Dec 9, 2018)

Finally got a replacement VFD. First one was indeed DOA. So the new one is up and running. I have had an old VFD on the drill press for a few years so with the new success I decided to take another look at that one. That unit has the fan running continuously as soon as power is applied. So my question is whether it is OK to just start and stop the VFD by applying power and cutting power to start and stop the drill press. That can mean a lot of powering up and powering down the VFD. I have it wired that way now and it works OK for my use but I am wondering if I am damaging the drive by the frequent start/stop.


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## ignator (Dec 9, 2018)

Gordon said:


> Finally got a replacement VFD. First one was indeed DOA. So the new one is up and running. I have had an old VFD on the drill press for a few years so with the new success I decided to take another look at that one. That unit has the fan running continuously as soon as power is applied. So my question is whether it is OK to just start and stop the VFD by applying power and cutting power to start and stop the drill press. That can mean a lot of powering up and powering down the VFD. I have it wired that way now and it works OK for my use but I am wondering if I am damaging the drive by the frequent start/stop.


If your switching the unit on and off by a power input switch to the drive, and have it programed to start automatically, that has deleterious effect on the electrolytic capacitors. The long term damage from surge charging current from a high count input power switching, is something to be avoided. I doubt they have charging circuits in these low cost VFDs.
On my drill press the VFD is mounted to the left side of the cast iron head. I just use the on off VFD control panel buttons, and the speed pot on the drive. I was not sure if your drive has the speed pot on the front panel, but looking at the manual the photo shows this.


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## Gordon (Dec 9, 2018)

ignator said:


> If your switching the unit on and off by a power input switch to the drive, and have it programed to start automatically, that has deleterious effect on the electrolytic capacitors. The long term damage from surge charging current from a high count input power switching, is something to be avoided. I doubt they have charging circuits in these low cost VFDs.
> On my drill press the VFD is mounted to the left side of the cast iron head. I just use the on off VFD control panel buttons, and the speed pot on the drive. I was not sure if your drive has the speed pot on the front panel, but looking at the manual the photo shows this.


I was afraid of that. Back to the way it was wired before. I was trying to eliminate the fan running when the drill press was not running. Thanks for the input. The unit on the drill press is a ABB Mini. If there is a way to shut off the fan I have not found it.


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## XD351 (Dec 9, 2018)

You can put a thermal switch in the wiring for the fan that will turn the fan on at a set temp , i watched a youtube video on this a few weeks ago but the hardest thing was getting the damned unit apart as they are not designed to be disassembled easily !  Like a lot of Chinese made gear they seem to like using small noisy fans for some reason , on my 3D printer this noise was unbearable so i fitted a bigger better quality and more importantly quieter fan - the cnc engreaver is next !


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## ignator (Dec 9, 2018)

Gordon said:


> I was afraid of that. Back to the way it was wired before. I was trying to eliminate the fan running when the drill press was not running. Thanks for the input. The unit on the drill press is a ABB Mini. If there is a way to shut off the fan I have not found it.


Have you looked through the manual for the ABB drive? What is the full model number of this.  I thought you got the replacement for the HuanYang that arrived dead. That does not have a program parameter to control any fan function. Other drives may have this.


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## EJay (Jul 18, 2019)

Hello to everyone,

I new to this site. I recently bought a teco VFD (p/n L510-203-h1-u) for my Enco 13x40 engine lathe. Does anyone have a schematic? I'm a machinist by trade. Not an electrician. So any help would be appreciated. I pulled off the front switch panel. There is a red(activates the motor switch),dark blue(activates green start button),light blue(activates coolant pump), and pink((hot wire which is ran thru all switches) which are ran to a buss bar on the back side of lathe. Can I hook up off the buss bar? Or should be hooking up on the other side of the contractors? I still having a hard time to decifering the wiring for the forward/reverse lever and the foot brake. Thanks for the help.


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## ignator (Jul 18, 2019)

EJay said:


> Hello to everyone,
> 
> I new to this site. I recently bought a teco VFD (p/n L510-203-h1-u) for my Enco 13x40 engine lathe. Does anyone have a schematic? I'm a machinist by trade. Not an electrician. So any help would be appreciated. I pulled off the front switch panel. There is a red(activates the motor switch),dark blue(activates green start button),light blue(activates coolant pump), and pink((hot wire which is ran thru all switches) which are ran to a buss bar on the back side of lathe. Can I hook up off the buss bar? Or should be hooking up on the other side of the contractors? I still having a hard time to decifering the wiring for the forward/reverse lever and the foot brake. Thanks for the help.


EJay; Welcome to this forum.
Do you have a schematic for your lathe?
You NEVER want to switch the outputs of a VFD, it can result in permanent damage to the output transistors.
So you want to integrate the VFD, using the FWD/REV micro switch signals from the traveling carriage control. You still want to keep the safety system in place of the lathe, so that it has to be in the not FWD not REV position before you can start the main lathe power up.
So you need to start at the wiring diagram for the lathe. You did not post a model number of your Enco lathe. See if you can find one online. If you have this, please scan it in and insert in this post.
Also that is a good VFD for this task.


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## EJay (Jul 18, 2019)

I have an 111-310 enco  lathe .model 1340. I would like to hook up before the contractors(maybe called a coil??). But not sure were to tie into it. The schematic that came in the owners manual is pretty much worthless. It only shows the wiring pertaining to R,S,T  (coming from the junction box to the main contractor)and U,V,W( going to the motor). I bought the teco L510-203-H1-U.


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## TonyM (Jul 19, 2019)

https://inverterdrive.com/file/Teco-L510-Manual-EN-v2

Plenty of info in this manual


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## cds4byu (Jul 19, 2019)

I have schematics for adding a VFD to the 13x40 so that the regular lathe controls work normally.  You can see my post here: 13x40.blogspot.com

Let me know if you need more information.

Carl


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## cds4byu (Jul 19, 2019)

EJay said:


> Hello to everyone,
> 
> I new to this site. I recently bought a teco VFD (p/n L510-203-h1-u) for my Enco 13x40 engine lathe. Does anyone have a schematic? I'm a machinist by trade. Not an electrician. So any help would be appreciated. I pulled off the front switch panel. There is a red(activates the motor switch),dark blue(activates green start button),light blue(activates coolant pump), and pink((hot wire which is ran thru all switches) which are ran to a buss bar on the back side of lathe. Can I hook up off the buss bar? Or should be hooking up on the other side of the contractors? I still having a hard time to decifering the wiring for the forward/reverse lever and the foot brake. Thanks for the help.



You will want to change your wiring in the control box on the back of the lathe, rather than the front switch panel.  I have a schematic for the necessary changes for two different types of VFD on my blog.  I think that your TECO uses the same wiring diagram as the AskPower listed on my blog.

If you have the manual for your lathe, it should have a wiring diagram, and you can see if it is the same as on my blog post.  I'd be happy to review your schematic if you'd like.
Carl


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## dazz (Jul 19, 2019)

Hi
I haven't read all the posts but I just want to reinforce a couple of points.
Firstly, don't expect to reuse any of the existing control and protection circuitry.  You should aim to reuse the hands-on switches, but not the relays, fuses and other stuff.  
Secondly, there is no substitute for reading and understanding the manual.   This especially includes understanding what you can't do, or don't need to do. 


This image is the  control and protection fitted to the Denford Viceroy for an ABB VFD.  None of the electrical components are original. 
 


A video of the finished Denford Lathe VFD Conversion

Here is a photo of the new control system for the Nardini lathe. 












IMG_8807



__ dazz
__ Oct 27, 2018



						Wiring in progress for a Nardini lathe VFD conversion.
					



  You can see from the hanging wires that this is still work in progress.  This was quite early on when I started wiring.  There is a lot more in there now.

The VFD is an industrial grade Yaskawa.  It took me two weeks to work my way through all the different settings plus another week of testing to confirm everything.

Here is the original control and protection for the Nardini.  All of this is gone. 




VFDs are not plug and play (at least the good ones aren't).  There is a significant amount of work required to install one properly.


Dazz


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## EJay (Jul 25, 2019)

cds4byu said:


> You will want to change your wiring in the control box on the back of the lathe, rather than the front switch panel.  I have a schematic for the necessary changes for two different types of VFD on my blog.  I think that your TECO uses the same wiring diagram as the AskPower listed on my blog.
> 
> If you have the manual for your lathe, it should have a wiring diagram, and you can see if it is the same as on my blog post.  I'd be happy to review your schematic if you'd like.
> Carl




Carl, 

Thanks for the help.    I took the front cover off to figure out the wiring for the switch panel. I downloaded your blog post. My wiring appears to be different. I don't have any contractors labeled "KM1" "KM2" or "kM3". So I'm a little lost following your blog. I currently have VFD wired directly to the motor. I attached a copy of my wiring diagram that came in my manual Along with some snapshots of the wiring in the back of the lathe. I'm not sure if I have "HY" series or the "ASK" series VFD. I bought a Teco L510-302-H1-U VFD. My FVD is a built in pontentiometer.


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## EJay (Jul 25, 2019)

EJay said:


> Carl,
> 
> Thanks for the help.    I took the front cover off to figure out the wiring for the switch panel. I downloaded your blog post. My wiring appears to be different. I don't have any contractors labeled "KM1" "KM2" or "kM3". So I'm a little lost following your blog. I currently have VFD wired directly to the motor. I attached a copy of my wiring diagram that came in my manual Along with some snapshots of the wiring in the back of the lathe. I'm not sure if I have "HY" series or the "ASK" series VFD. I bought a Teco L510-302-H1-U VFD. My FVD is a built in pontentiometer.


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## ignator (Jul 26, 2019)

That wiring diagram has a bit of confusion built in. It shows 3 different motor optional connections on the one diagram; the top diagram is single phase 220v, the next one down is single phase 110 volt, and the 3rd is 3 phase 220volt. I believe the 3 phase model has a coolant pump, as shown as M2 (motor 2).
Then there is the control and safety interlock at the bottom of the page. That is fed through a transformer for 24volt contactor coils. I become lost at the switches where FWD and REV are enabled. It appears these should be single pole double throw switches, but something is drawn wrong in my mind.
I also agree that using the motor contactor contacts is the way to control the VFD for FWD/REV.
There appears to be 3 limit switches used for interlock and FWD/REV control. L1, L2, L3. Then there are 2 push button PB1, PB2, that I think are start and stop related. The C contactor is the interlock to ensure there is no FWD/REV active with power on.


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## lemelman (Jul 27, 2019)

I fitted a VFD to my 12x36 lathe a few years ago. I replaced the motor, used a Mitsubishi inverter, and wanted to retain all the original switching gear and just add a speed (frequency) control. I was somewhat dismayed when I opened the control box to find a mass of relays with wires everywhere. It looked horribly complicated.
It then occurred to me that all that complexity was to provide 2 major functions..
1. Provide a No Volt Release (NVR) system
2. Allow the Forward/Reverse switches to switch the motor on/off in the required direction.
Apart from the NVR, everything else can be done with the VFD.
It was obvious that the mains voltage went straight to a relay called *KM1*. A simple multi-meter set on AC Volts showed that terminals *3* &* 5* of *KM1* became live only *after* the lathe POWER START button was pushed, and stayed live until the mains lead was disconnected. This was the NVR, and all the other relays could be ignored.
The other important section in the control box was a long terminal strip. I removed the mains plug and, with the multi-meter set to resistance, determined what terminals were connected when the lathe was switched to *forwards *or *backwards.*
The diagram *Diag-1* shows the important terminals on my lathe.
I could then wire KM1 terminals 3 & 5 straight to the VFD power input and connect the wires that used to go to terminals 7,7,13,5,5,4 to a new chocolate strip as shown in *Diag-2*.
I then made up a couple of  3-core cables to connect the chocolate strip to the VFD control terminals. These are all low voltage. I never used the inching control of the lathe so I removed the switch and replaced it with a speed ctl potentiometer for the VFD, and added a nice scale.
The VFD terminals in Diag-2 show those for my Mitsubishi; yours will probably be different, but will have the same function.
Everything on the lathe works as it did before, except I now have a speed control knob too.


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## cds4byu (Jul 28, 2019)

Ejay,

I've been looking at your control box and your wiring diagram.

As is, your wiring diagram may or may not make lots of sense to me.  Are there any other wiring-related pages in your manual (e.g. a component layout diagram)?

Let me ask you a couple of questions:

1. Does your lathe have an E-stop button?

2. Does your Start button have a light that turns on and stays on when you press it?

3. Can you run coolant without the power start light on?

Then I have a couple of questions about your photos of the control box

1. Can you take some photos of the lower right corner, preferably that show  the numbers on the white rings on the wires?

2. Can you tell me where the wires that go out of the box in each of the wire ports?

Finally, you said you have a 111-310 lathe.  I can't find any references to that model.  I see a 111-3110 and a 111-3310.  Can you confirm your model number?

I hope to get you some good answers about how to hook up the VFD.

Thansk,

Carl


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