# Can this motor be wired for 110v?



## kd0afk (Jan 17, 2014)

I'm rebuilding a model 1180 shaper and I don't have 220. I'd rather not have to buy a new motor. Anyway here's the data plate. How else can I figure out if it can be rewired.


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## dave-in-england (Jan 17, 2014)

.

Will probably be cheaper just to buy another second-hand motor than have this one re-wired. 

.


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## kd0afk (Jan 17, 2014)

OK, thanks. I didn't think it was a have to get it rebuilt thing I thought it was more of a I could do it.


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## kd0afk (Jan 17, 2014)

Here's the wires coming out of the motor there are four, red, white, black and green.


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## Mechanicboy (Jan 18, 2014)

If the electric motor is designed for 220 volt, you can not rewiring to 110 volt. There is the winding in the electric motor which determines the voltage. Best to buy new or used electric motor.


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## kd0afk (Jan 18, 2014)

Okay thanks


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## Omnimill (Jan 18, 2014)

Does it actually run at all on 110V? I only ask because I used to run a milling machine that was rated 440V 3 phase on a 240V single phase supply. I had to swap some wires over and connect a large capacitor across a couple of wires but it ran fine, albeit at 80% of rated capacity.


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## Tin Falcon (Jan 18, 2014)

If you have a reputable motor shop or electrician they can advise you.  I have and have seen motors set up to run 110/220 but they are usually labeled and have diagrams to set the voltage.
That said  If it was me I would likely just run a 220 line. 
Most homes in the USA have 220 available it is just split into two 110 legs in the breaker box just a matter of installing a breaker a bit of romex and a 220 outlet. 
But if you are not comfortable with electric work. Probably cheaper to buy a motor over hiring an electrician. 
How far is your work area from your breaker box.


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## ShopShoe (Jan 18, 2014)

What Tin said.

If you need the same HP, current will be double at 110V, possibly calling for another circuit anyway. Starting current may also be higher (motor guys can confirm this?) If you can install a 220V circuit, that is probably best. 

Otherwise, just look for another motor.

--ShopShoe


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## kd0afk (Jan 18, 2014)

Tin Falcon said:


> ...
> How far is your work area from your breaker box.


Too far, they are in separate buildings


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## kd0afk (Jan 18, 2014)

I've found some motors on eBay for around $100 that will work. I would say I got a pretty good deal on this shaper. A new set of bearings, swapping out all of the nuts and bolts for stainless, two cans of spray paint and one can of easyoff and some elbow grease and a new motor. The shaper was free. 
 I'll probably get this motor working and sell it. And when the thing is working ill sell it to buy a thickness planer.


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## kd0afk (Jan 18, 2014)

They sell a step up transformer that let's you run 220v appliances on 110v mains. Could that be an option or is it too simple to work?


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## Tin Falcon (Jan 18, 2014)

sure it will work but will draw twice the amps and run your electric meter twice as fast and you will pay twice for the electric it uses.  Se la vi
Tin


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## kd0afk (Jan 18, 2014)

Tin Falcon said:


> sure it will work but will draw twice the amps and run your electric meter twice as fast and you will pay twice for the electric it uses.  Se la vi
> Tin



So you're saying a 220v motor run on a step up transformer would eat four times the electricity than a 110v motor?


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## Tin Falcon (Jan 18, 2014)

No  I am saying your motor rated at 220 volts  and three amp powered by a  step up transformer will draw 6 + amps off a 110 main   .  And since your billing is based on amp draw you will be billed based on the 6 amps flowing through your meter. 
The overall power consumption will be about the same . Power is amps times volts. so if the volts are cut in half the Amps are doubled to obtain the same power. 
Sorry if I confused the issue. 
Tin


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## kd0afk (Jan 18, 2014)

So it would cost roughly the same to run than a normal 220 motor? If I had a 220 outlet to use I would be using that power so I won't be any worse off right? I think I will go ahead and get a new motor though.


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## Tin Falcon (Jan 18, 2014)

Any of the electricians can correct me if I am wrong but it is my understanding motors running on 110 cost more to run than a comparable power 220 motor or the same dual voltage motor wired 110 will cost more to run than wired in 220 mode.
Tin


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## barnesrickw (Jan 18, 2014)

From what I remember from all the pumps I ran, Tin is correct.  Amperage is higher at reduced voltage.


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## RonGinger (Jan 19, 2014)

This is getting a little of the mark. We are measured for our POWER drawn, not just the amps. So if we use 1hp of mechanical we will pay for 1hp+ some loss of electricity. It doesnt rally matter if we use the power at 110v or 220v, power is power. Transformers happen to be about the most efficient electrical gadget around, so if use one to change voltage we use very little more power.

It is true that the same motor, doing the same work, will take twice the current flow at 110 as at 220. But 2x current at 1/2x voltage is still the same power.

The reason we want to run the motor at the higher voltage is to lower the current, because the current will cause a power loss in the wires based on the wire resistance. So we like to run motors at the highest voltage, hence lowest current we can.

If the motor is run at 110v, the higher current will cause more line loss, and the voltage at the motor will be reduced from the 110 at the wall to maybe as low as 90 or so, the extra power lost to heat up the wires. So we waste power and the terminal voltage of the motor is lower so we get less power out of it.

When is all added up we are better off running a motor at 220v than at 110v if its possible.


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## MachineTom (Jan 19, 2014)

A 1/2 HP 110 motor will cost the same to run as a 1/2 hp single phase 220 motor. At half the voltage the current is doubled, so wattage is the same regardless the voltage.

220 coming into a house is two lines that each are 110v to neutral. And 220v line to line. The meter reads the current on each line and adds them together. So the meter spins the same speed if its 10 amps on one line and and zero on the other, or 5 amps on each line.


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## kd0afk (Jan 19, 2014)

Please don't think I'm stupid, but why can't a 220v motor be run on 110v?  Wouldn't it just run half as fast? Electricity is not my strong suit.


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## Tin Falcon (Jan 19, 2014)

No not that simple. it goes back to amps and volts . Lets use pluming and pipes as an illustration but not a direct correlation if you will. 
VOlts have been compared to pressure in a pipe amps is the flow rate. 

But try to pump water through a small pipe and only so much will flow it will take for the sake of argument twice as long to fill a bucket. 

with wires the more flow you need the bigger the wire. the wires in your motor are designed for 3 amps based on 220v  cut the voltage to 110 and the motor will attempt to draw the same power therefore 6 amps. but since the wire is too small for this flow the wire will act somewhat like a heating coil and generate heat. this heat generation will kill efficiency and potentially melt insulation and short out/burn out the motor. 
I do not recommend trying it.
Tin


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## BaronJ (Jan 19, 2014)

kd0afk said:


> Please don't think I'm stupid, but why can't a 220v motor be run on 110v?  Wouldn't it just run half as fast? Electricity is not my strong suit.



An induction motor speed is controlled by the frequency of the supplied electricity.

You will probably find that it will run on 110 at its rated speed but its output power will fall dramatically.

A suitable transformer would be the cheapest option if you can't get at 220V.

HTH.


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## Wizard69 (Jan 20, 2014)

kd0afk said:


> Please don't think I'm stupid, but why can't a 220v motor be run on 110v?  Wouldn't it just run half as fast? Electricity is not my strong suit.




This has been already covered by other but I'm going to try to add clarity (and probably confuse a few people)

AC machines have their rotational speed defined by the line frequency they run at.  That is 60 HZ in the modern world.  However most AC motors are not synchronized with the line frequency so the actual speed is the synchronous frequency minus slippage.   Voltage has little to do with the motor trying to run at design speed.  

This is why 3 phase motors use variable frequency drives to change their operating speed.  These drives do vary the voltage slightly to the motor but that isn't done to change speeds so much as to deal with other issues.  

Now why can't you run a motor at a reduced voltage, if it is frequency dependent?    That gets involved in motor design to a greater extent than we really want to get into, but in simple terms the winding are design to operate at a specific voltage or sets of voltages.


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## BaronJ (Jan 21, 2014)

Hi Wizard69,

It seems nitpicking but I would replace the words "AC machines" by "Induction Motors".  Simply because an ac machine could be a universal motor which could equally well run from an ac or dc supply and also be voltage dependant for its speed.


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## Alchymist (Jan 21, 2014)

RonGinger said:


> This is getting a little of the mark. We are measured for our POWER drawn, not just the amps. So if we use 1hp of mechanical we will pay for 1hp+ some loss of electricity. It doesnt rally matter if we use the power at 110v or 220v, power is power. Transformers happen to be about the most efficient electrical gadget around, so if use one to change voltage we use very little more power.
> 
> It is true that the same motor, doing the same work, will take twice the current flow at 110 as at 220. But 2x current at 1/2x voltage is still the same power.
> 
> ...



While your bottom line is true to a certain extent, unless large motors and long wire runs are involved, it is for all practical purposes moot. The motor in question, if it could be run on 120 v, would draw about 7 amps. Even an ordinary circuit of #14 wire on a 15 amp breaker would run this just fine, and most circuits today are usually #12 on a 20 amp breaker. It would take a very long run of #14 to reduce a 120 volt source to 90 volts when drawing 7 amps.

Here's a sample calculation for 500 feet of #14:
1 conductors per phase utilizing a #14 Copper conductor will limit the voltage drop to 5.64% or less when supplying 7.0 amps for 500 feet on a 120 volt system.
For Engineering Information Only:
15.0 Amps Rated ampacity of selected conductor
2.9495 Ohms Resistance (Ohms per 1000 feet)
0.058 Ohms Reactance (Ohms per 1000 feet)
24.0 volts maximum allowable voltage drop at 20%
18.759. Actual voltage drop loss at 5.64% for the circuit
0.9 Power Factor

Handy calculator here:
http://www.southwire.com/support/voltage-drop-calculator.htm


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## kd0afk (Jan 21, 2014)

You guys are way above me electrically 

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## BaronJ (Jan 21, 2014)

kd0afk said:


> You guys are way above me electrically
> 
> Sent from my C6606 using Model Engines mobile app



Hi kd0afk,

Understanding electricity is not easy.  There is a lot of good, sound information in these few posts.  The bottom line is, simply get access to a 220 volts supply or replace the motor with one having the correct voltage.  As I said earlier a transformer will do what you want and should be way less costly than a new motor.


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## barnesrickw (Jan 21, 2014)

So now that you solved that, how can I make my sewing machine motor AC 110v universal type, run backwards.


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## Alchymist (Jan 21, 2014)

barnesrickw said:


> So now that you solved that, how can I make my sewing machine motor AC 110v universal type, run backwards.



Reposition the brushes!

On edit: If it's universal, run it on DC! Polarity then determines direction.


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## Noitoen (Jan 21, 2014)

Usually it's quite easy to get a a 220V motor running on 110V. That motor is a 2 pole motor and the windings (1 pair of coils each start run) should be connected in series. If this is the case, they can be reconnected in parallel without the need to rewind it. A little patience and you can do it yourself. I've had a motor repair shop for many years and I've done it before. If you want "long distance" help, I can walk you through it.


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## Wizard69 (Jan 21, 2014)

BaronJ said:


> Hi Wizard69,
> 
> 
> 
> It seems nitpicking but I would replace the words "AC machines" by "Induction Motors".  Simply because an ac machine could be a universal motor which could equally well run from an ac or dc supply and also be voltage dependant for its speed.




You are right of course.   There are actually a number of motor designs out there but in the case of machinery the vast majority if the AC motors are of the induction type!    If you work with them on an almost daily basis you forget about all of the variations.


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## Wizard69 (Jan 21, 2014)

BaronJ said:


> Hi kd0afk,
> 
> 
> 
> Understanding electricity is not easy.


I wouldn't say it is difficult but formal education does help.   Motors where covered in part of one quarter of my electrical mechanical technology program.    It is one part of my education that has actually been helpful after finishing that two year program.   That and I managed to take an industrial electricity course at a tech school night program one fall.  

It isn't that the subject matter is difficult it is just that you don't get exposed to it at all during most educational experiences.  


> There is a lot of good, sound information in these few posts.  The bottom line is, simply get access to a 220 volts supply or replace the motor with one having the correct voltage.  As I said earlier a transformer will do what you want and should be way less costly than a new motor.




Personally I'd install the 220 circuit or in the case of this poster have an electrician do it.   The circuit will be very useful for an air compressor, small mig or inverter welder or other tools that migrate to the shop.  

Speaking of circuits I have one branch circuit waiting on an install in the cellar right now.


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## BaronJ (Jan 22, 2014)

Alchymist said:


> Reposition the brushes!
> 
> On edit: If it's universal, run it on DC! Polarity then determines direction.



Yes !  That's the easy way...

The hard way is to swap the ends of the field winding.  Near impossible to do on some motors.


As an aside:
I have a universal fractional horse power motor, very similar to your sewing machine one.  Its a 100 watts rating that started life on a Creed Teleprinter.  It was made in 1947 by LFM. It has a very useful 3/8" shaft and runs at a nominal 3000 rpm.  The ends of both field windings come out to a terminal block mounted on the side.  This terminal block is marked 110v, 220v  with a flying lead on each side.  Swapping these wires around will cause the motor to run the other way on AC.  The motor originally was set up to run on DC 100volts  This was because the motor when set up on the teleprinter had a large centrifugal governor that broke the supply voltage when the speed went above 3000 rpm.

This motor currently drives my small drill grinder via a triac speed controller.


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## bb218 (Jan 22, 2014)

Correct me if I am wrong but with 220V you would have 2 hot leads that are 110v each that are out of phase.  If you used a transformer and upped the 110V to 220V you would have 1 hot lead that was 220V  I don't think this would work to run a 220V motor    Mike


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## RonGinger (Jan 22, 2014)

This use of 'phase' is widely misused. In fact the wire coming into your home is from the 2 ends of a transformer out on the pole. This transformer has a center tap, so from the center tap to either end you find 120v. The 240v wires are the same phase, but will be opposite in polarity- one end goes plus while the other end goes minus. But its still only one phase.

Many people, electricians included, will refer to these two wires as phases but they are not.

If you  take a 2:1 ratio transformer, hook it to the 120 v line and neutral, the transformer will have exactly the same output as the two wires coming into the house- one end will be positive while the other is negative. What you will not have is that circuit reference to neutral, or ground. It will run the 240v motor just fine.


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## kd0afk (Jan 23, 2014)

I have a 3/4hp 110v motor that only runs at 1750rpm. I use a larger pulley on the motor to double the speed right? It shouldn't hurt performance right?

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## kd0afk (Jan 23, 2014)

The reason why I don't install a 220 line in the garage is because I rent and the landlord is a butt hole. The garage my tools are in has 4'x8' storage units for the tenents and a common area. My lathe is in my unit. There is also a back room to the garage; 12'x25'. I've asked him on several occasions to rent the space for a $150/month but he says he needs it for his maintenance guy. His maintenance guy has NEVER been in the garage once. 
It wasn't "no, that's not not enough money", or "I'm renting it out already". I don't understand people. I was given a Fleetwood motorhome a few months back and I was going to fix it up and sell it. The landlord told me it had to go. He gave me a time limit to move it that didn't give me a chance to sell it so I had to pay to have it hauled away. The motor needed some work but the body was in pristine condition so it wasn't an eyesore. I explained that if he gave me a month it would be gone and I could make some money by selling it. He said he couldn't have it. I live in a industrial/residential area and it was not out of place and the neighbors were fine with it. The landlord lives two towns over also. 
How do you deal with a guy like that?

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## Alchymist (Jan 23, 2014)

bb218 said:


> Correct me if I am wrong but with 220V you would have 2 hot leads that are 110v each that are out of phase.  If you used a transformer and upped the 110V to 220V you would have 1 hot lead that was 220V  I don't think this would work to run a 220V motor    Mike



You are wrong. Notice in the crude drawing, a 240 volt motor would normally connect to points A and C in the main panel drawing. By using a step up transformer as in the motor circuit shown, the motor sees the exact same 240 volts as it would if wired direct.Transformers are neat devices, can step voltages up and down, provide taps, references, etc, and are one of the few devices almost 100% efficient.


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## Alchymist (Jan 23, 2014)

kd0afk said:


> I have a 3/4hp 110v motor that only runs at 1750rpm. I use a larger pulley on the motor to double the speed right? It shouldn't hurt performance right?
> 
> Sent from my C6606 using Model Engines mobile app



Depends on your definition of performance. There are two factors to consider - speed and torque, torque being the amount of twisting force applied to the load. A given motor running at say 1750 rpm, will develop a fixed amount of torque at that speed. Ignoring minor factors, putting a small (say 2")pulley on the motor, and a 4" on the load, the load will be driven at half the motor speed, (875 rpm), but with twice the available torque.

Reverse the pulleys, with the 4" on the motor and the two inch on the load, the load will be driven at twice the motor speed, but with only half the torque available. 

In essence the speed is determined by the load requirements, and pulley sizes selected to produce that load speed. Torque, on the other hand, is also determined by the load requirements, and is achieved by selecting the right sized motor - the more torque required at the speeds and pullies selected, the bigger the motor needs to be. Hope this helps.


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## BaronJ (Jan 23, 2014)

kd0afk said:


> I have a 3/4hp 110v motor that only runs at 1750rpm. I use a larger pulley on the motor to double the speed right? It shouldn't hurt performance right?
> 
> Sent from my C6606 using Model Engines mobile app



This depends upon what you perceive as performance.
In practice you can't get more power out than you put in.  Yes you can double the speed by making the motor pulley larger but the torque will be less.

As an example 1 horse power is 746 watts so your 3/4HP motor will draw 560 watts.  This is also the maximum output power less any losses.  These losses are seen as heat.  Its the reason the motor warms up.  As you increase the load on the motor the losses increase and the motor warms up even more.

So when you have doubled the speed if you don,t try to take more energy out than you put in all will be OK.


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## kd0afk (Jan 23, 2014)

I knew there was a loss somewhere. Thanks

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## dman (Jan 25, 2014)

3/4 hp is 3/4 hp and speed is a factor of hp. by that reasoning that faster motor has half the torque by default. since the 3/4 hp is more than the 1/2 hp i think you'd be clear with that combo assuming you can find the needed pulley, the difference in thermal losses won't be enough to need over 50% more power. 

anyway, if you have heavy enough wire going to the main panel you might be able to make it a 220v circuit. i never saw a 15 amp common trip (220v) breaker so you would need more than 14 gauge wire, if you have 12 gauge you can get a 20amp breaker, put a sub panel into the area and use that to distribute the ground as ground as well as neutral and allow you to add breakers for 110v. basically when you have 2 circuits on opposite phases/polatiry you are allowed to share a neutral because the only current on the neutral is the difference current between the two hots, as far as grounds you can share grounds over multiple circuits and the sizing needs only be as large as the required for the largest circuit and not a combined value of all the circuits. i don't know how you have the wiring but there are several ways you may be able to convert to 220v without adding new wires in the case that the breaker isn't rated higher than the wires. 

if that's not an option you can get an auto transformer. which is a single coil transformer and are found used on ebay for stepping up/down ac power. you may find them with many taps for multiple voltages. with an auto transformer that is only made for one step up/down there are 3 connectors. one for each phase in and an extra one for the step in voltage. you would use one of the conductors from the supply voltage to complete that circuit. 

as far as the motor, i can't read the plate, i'm assuming it's a single phase? if it's 3 phase you need a phase converter and there are power inverting phase converters. i'm not sure if they make passive phase converters that way (but you can add an auto transformer) but a variable frequency drive would be available in a step up version with 110v in and 220v out (but these only put out 3 phase, leaving a phase open would be very bad). i'm having pretty good success with a cheap generic Chinese vfd on my knee mill.

there are several ways that you may be able to go but i can't say which is best without seeing your home.


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## cfellows (Jan 25, 2014)

This is more of a question than a suggestion, so if you decide to try this, understand that you may blow a circuit breaker (or worse)

 Since the white wire would normally be neutral and the red and black wires go to the opposite 110v polarities, wouldn't it work on 110v if you hooked the 110v ground side to the white wire and the 110v hot side to both the red and black wires?  You would be doubling the amps but it still shouldn't be more than 10 or 12 amps under full load, right?

 Chuck


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## BaronJ (Jan 25, 2014)

dman said:


> 3/4 hp is 3/4 hp and speed is a factor of hp. by that reasoning that faster motor has half the torque by default. since the 3/4 hp is more than the 1/2 hp



No it is not !  The speed of an induction motor is a function of the supply frequency and the number of poles the motor is wound with.


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## BaronJ (Jan 25, 2014)

cfellows said:


> This is more of a question than a suggestion, so if you decide to try this, understand that you may blow a circuit breaker (or worse)
> 
> Since the white wire would normally be neutral and the red and black wires go to the opposite 110v polarities, wouldn't it work on 110v if you hooked the 110v ground side to the white wire and the 110v hot side to both the red and black wires?  You would be doubling the amps but it still shouldn't be more than 10 or 12 amps under full load, right?
> 
> Chuck



Hi Chuck,
You cannot safely connect the red and black wires together !  That would cause a short circuit across the pole transformer.


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## cfellows (Jan 25, 2014)

BaronJ said:


> Hi Chuck,
> You cannot safely connect the red and black wires together ! That would cause a short circuit across the pole transformer.



 Baron, I'm talking about the red and black wires in the motor, not the ones from the breaker box or mains.







 Chuck


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## dman (Jan 25, 2014)

BaronJ said:


> No it is not !  The speed of an induction motor is a function of the supply frequency and the number of poles the motor is wound with.



absolutely, that is what regulates the speed, but that's unreleated to what i'm saying.

hp is rpm*torque(in ft/lb)/5252... so if the power is equal and you half one factor the other must double. i understand that the power consumption and production depends on load and they don't constantly draw the rated hp without regard to load and bogging a motor will create slippage in the core and result in heat generating eddy currents and los of efficiency. i'm not saying bogging a motor to half speed would create the same hp and power draw. 

what he asked is if he could substitute a 2 pole 3500rpm motor with a 4 pole 1750rpm motor and make up the difference with a bigger primary pulley. we are not talking about bogging a 3500rpm motor down to 1750 rpm... that would be silly. and what i'm saying is that if the rate of work is the same ( it will be if the second pulley effectively spins the same speed which is what our goal is in using a bigger pulley with a motor that has more poles) then the power consuption is the same and the motor rated hp requirement is the same so actually increasing the rated hp because he happens to have one will only give a surplus of power which isn't always a bad thing.


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## RonGinger (Jan 25, 2014)

Chuck your idea might work depending on the motor, but all the motors Ive seen for 240v do not have the center tap wire. The white may simply be a shell ground- although that ought to be green.

If this were a 120/240v motor then it would work, but there would have to be more wires.


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## Noitoen (Jan 26, 2014)

I've rewound thousands of motors in my time and insist, he should open the motor and inspect the winding connections. If they are in series, all he has to do is, disconnect this connection, solder 4 new wires and end up with a 120/240V motor in 30 minutes.


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## BaronJ (Jan 26, 2014)

cfellows said:


> Baron, I'm talking about the red and black wires in the motor, not the ones from the breaker box or mains.
> 
> 
> 
> ...



Hi Chuck, apologies for my confusion.  I thought you meant from the breaker box.
I hadn't realised that the wires in the motor were those colors.

Sorry. :wall:


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## BaronJ (Jan 26, 2014)

dman said:


> absolutely, that is what regulates the speed, but that's unreleated to what i'm saying.
> 
> hp is rpm*torque(in ft/lb)/5252... so if the power is equal and you half one factor the other must double. i understand that the power consumption and production depends on load and they don't constantly draw the rated hp without regard to load and bogging a motor will create slippage in the core and result in heat generating eddy currents and los of efficiency. i'm not saying bogging a motor to half speed would create the same hp and power draw.
> 
> what he asked is if he could substitute a 2 pole 3500rpm motor with a 4 pole 1750rpm motor and make up the difference with a bigger primary pulley. we are not talking about bogging a 3500rpm motor down to 1750 rpm... that would be silly. and what i'm saying is that if the rate of work is the same ( it will be if the second pulley effectively spins the same speed which is what our goal is in using a bigger pulley with a motor that has more poles) then the power consuption is the same and the motor rated hp requirement is the same so actually increasing the rated hp because he happens to have one will only give a surplus of power which isn't always a bad thing.



Thanks for the clarification.  Your post was a little unclear.


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## BaronJ (Jan 26, 2014)

Noitoen said:


> I've rewound thousands of motors in my time and insist, he should open the motor and inspect the winding connections. If they are in series, all he has to do is, disconnect this connection, solder 4 new wires and end up with a 120/240V motor in 30 minutes.



I saw your original post and was going to comment.

Yes I completely agree with you.  An inspection of the windings would reveal all.


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## kd0afk (Feb 1, 2014)

I just saw another motor that can be wired for both 110 and 220. The data plate states that. That's where I was getting fouled up. I thought a 220 motor could be wired for 110 but now I realize that it has to be made that way to be wired that way. Didn't realize it had to be made that way. 

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## kd0afk (Feb 1, 2014)

I just ordered a step up/down 100 W transformer. I'll try that and see how it does. I will probably git rid of the plastic case and mount it in a box with a fuse and cooling fan. 
I remember living in Germany as a kid all of our appliances were 110v so we had to use this 20 lb transformer. 

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## Herbiev (Feb 1, 2014)

If the motor is 3/4 hp that is about 560 W so a 100 W transformer probably won't do.


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## kd0afk (Feb 1, 2014)

It's 1/2 hp. But it's amps x volts. It's a 3.5 amp motor and at 220v it would mean I need a 770watt transformer?  I just looked and found a 1000w up/down power converter for $50. 

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## dman (Feb 5, 2014)

kd0afk said:


> It's 1/2 hp. But it's amps x volts. It's a 3.5 amp motor and at 220v it would mean I need a 770watt transformer?  I just looked and found a 1000w up/down power converter for $50.
> 
> Sent from my C6606 using Model Engines mobile app



that sounds like a perfectly reasonable price..

the running amps are probably less than the amps rating. that could be starting current or max load current. i'd hate to think an asyncronous induction motor is 50% efficient, and the actual machine load will ahve something to do with the actual current. i mean there will be a minimum free spinning current. a stalled current, and a start current. when it's free spinning/no load it's doing no work, and when it's stalled it's doing no work. in these situations you have 0% efficiency. but in the right load range the motor should be quite efficient. but i'm not really sure how they come up with the ratings. the hp can be something like the power it produces without heating up. it may acutally produce more if the load demands it. and the current isn't necessarily the running current at the rated hp... either way it would help to have a somewhat bigger transformer than the math suggests if for nothing more than piece of mind..


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## kd0afk (Feb 5, 2014)

I think the transformer would be the best option. I've priced motors and it seems that the higher the voltage the less expensive. 

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## BaronJ (Feb 5, 2014)

Hi Guys,
The ratings on the motor plate are the full load current and voltage.  There is often a temperature or temperature class rating code.  This is the temperature that shouldn't be exceeded when the motor is running normally.  There may also be other information on the rating plate such as HP, shaft size, rotation direction and wiring data.  Sometimes there is information about the starting type CF or CSR. 

The one thing that usually isn't on the rating plate, at least on smaller motors <3Hp is starting current, which can be three to five times the running current.  The starting current usually only lasts for a very short time, but it is something to be aware of.  I've seen motors mistakenly scrapped because feeding fuse or breaker has tripped.


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## kd0afk (Feb 10, 2014)

To tell you the truth, I don't even know if the motor works. How bad would it be to plug the motor into the 100W transformer just to see if it works?

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## kd0afk (Feb 10, 2014)

If the motor works I'll go ahead and buy the 1000W transformer. 

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## BaronJ (Feb 10, 2014)

kd0afk said:


> To tell you the truth, I don't even know if the motor works. How bad would it be to plug the motor into the 100W transformer just to see if it works?
> 
> Sent from my C6606 using Model Engines mobile app



Hi there,
You might just find that the transformer lets the magic smoke out !  It wont damage the motor but the transformer would be toast.

Really you would be better off finding someone who can run a test on it for you.


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## cfellows (Feb 11, 2014)

In my experience, you're not likely to damage the transformer if you momentarily connect it to the motor, even if it's a dead short.  However, when I say momentarily, I mean no more than 2 or 3 seconds.  

 The other thing to note is that 100 watts may not be enough to start up the motor.

 Chuck


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## kd0afk (Feb 11, 2014)

Is there a way to test the motor to see if there are any shorts in the windings? 

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## cfellows (Feb 11, 2014)

I'm no electrician or electrical expert, but in my opinion, it would be hard to tell.  Normally I would say use an ohmmeter to measure the resistance of the windings, but without knowing what the resistance should be, it would be hard to interpret any results.  I'm guessing the resistance is going to be pretty low, even if there is no short.

 Chuck


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## kd0afk (Feb 12, 2014)

I do have a 220 plug available. The dryer I'd plugged into it. I can't use is full time but I can use it to test the motor. I bought  a dryer plug and I replaced the old switch. I hope I got it right. I wired the white to the "L" shaped prong and the black and green to the flat prongs. Did I do good?  
If the motor is good I'm going to buy a transformer. 

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## BaronJ (Feb 12, 2014)

kd0afk said:


> I do have a 220 plug available. The dryer I'd plugged into it. I can't use is full time but I can use it to test the motor. I bought  a dryer plug and I replaced the old switch. I hope I got it right. I wired the white to the "L" shaped prong and the black and green to the flat prongs. Did I do good?
> If the motor is good I'm going to buy a transformer.
> 
> Sent from my C6606 using Model Engines mobile app



If you do test it then beware of the kick as the motor starts to spin.  Trap it between a wall and your foot !  If you don't it may spin out of control and do some damage.
Take care.


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## ShopShoe (Feb 12, 2014)

kd0afk,

I hope you haven't tried to run this motor yet. If you are in the USA, I am concerned about what you are doing!

"I wired the white to the "L" shaped prong and the black and green to the flat prongs. Did I do good?"

Green is supposed to be ground. White is neutral in 110V or a hot wire for 220, which may be connected to ground in 110V. This is confusing, but there are reasons why it is so, by convention and by code.

With the power off, use an ohmmeter (on the lowest setting) to check for continuity from the green wire to the housing of your motor.

If the green wire IS ground, you are creating a situation where the motor housing is connected to current and you can be shocked.

You may have also created a situation where you have a dead short and your circuit breaker will trip or fuse will blow.

I usually am not one to discourage individual learning: This is a learning forum. I strongly suggest getting help from someone who has more experience with electrical installations in your location and/or someone who has definite experience with the internals of motors like yours. You need an experienced set of eyes and hands to help you in a hands-on way with this. We can only offer general advice online, and electrical codes and practices differ in different parts of the world. Someone may have patched-together your motor in a non-standard way, which also complicates our understanding and advice.

I researched transformers myself, but found that suitable ones for your use would approach the cost of a suitable motor. You should be able to find a better motor and get rid of this one.

I have been in your situation and have gotten rid of running motors, rather than end up with something not right and possibly unsafe.

Please be careful.

--ShopShoe


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## kd0afk (Feb 12, 2014)

So, I wired the white wire to the "L" shaped prong. The motor according to the PO is functional. The old plug was like a 110 plug but the blades are in line. The white wire was wired to the round post on the old plug. I'm confident that the motor isn't shorted, I just need to know if the plug is hooked up right. 

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## kd0afk (Feb 12, 2014)

And the motor is mounted so no kick back. 

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## kd0afk (Feb 12, 2014)

The cords are in bad shape so I just bought 2 feet of 10/4 to go from the motor to the switch and 10 feet of 12/3 to replace the plug cord. 
I'm going to duplicate the wiring. I'm pretty sure I can do it right with the wiring diagrams. 

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## kd0afk (Feb 16, 2014)

Just had someone help me move it the 220 outlet and it works just fine. I'm going to replace all of the old cord and try to sell it to put towards a milling machine. 

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## BaronJ (Feb 17, 2014)

kd0afk said:


> Just had someone help me move it the 220 outlet and it works just fine. I'm going to replace all of the old cord and try to sell it to put towards a milling machine.
> 
> Sent from my C6606 using Model Engines mobile app



Well at least you now know !


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