# Where to find used AC motors?



## wilkes5 (Jun 1, 2012)

Looking to find a used (maybe a burnt out one) AC motor which can be rewound for 120 volts and higher currents. Want to match it to a Curtis controller 1238-6501 (or something simular). Have email lots of motor shops around my area with the specs....

*1--20 hp maybe with a vf rating, it would have a longer stator, about
seven inches in lenght. Yes you want the longer stator.

2--2 pole 3450 rpm, motors are likely to have more back iron.

3-- 208, 220, 440 volt, or just 208, 220

4--aluminum housing, motor weight would be about 225 lbs

5--C face (pump motors)

6--totaly enclosed fan over, that gives you a tail shaft for the encodder.

7--should have 48 SLOTS to do new rewind 4 pole.*

BUT haven't had any luck finding one. Do you know where to find a motor like such and maybe someone who can rewind? Maybe you have an opinion or differen't specs to go by when looking for a motor to EV install? 


Always what is right
Austin


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## Siwastaja (Aug 1, 2012)

wilkes5 said:


> *
> 2--2 pole 3450 rpm, motors are likely to have more back iron.
> *


I have been told by an expert (and agree with my own common sense) that a 4-pole stator frame would be best for doing a 4-pole rewind; 2-pole indeed has more back iron, but it has thinner teeth and this might pose a problem.

In the rewind, you are going to keep the magnetic flux identical so the original iron configuration still should be optimal. You are just lowering voltage and increasing frequency to drive more power with the same flux.

Furthermore, if the number of poles of the original winding equals the new pole number, it's way easier to plan the rewind; just copy the windings and reduce the number of turns in all windings by the ratio of the new voltage : old voltage, and increase the number of parallel wires by the same ratio. For example, 30 turns per slot with 3 parallel wires would become 6 turns with 15 parallel wires when decreasing nominal voltage from 400Vac to 80Vac. Then, the power could be doubled at 160Vac = 220Vdc by doubling the frequency (and rpm) at the same time.



wilkes5 said:


> *
> 7--should have 48 SLOTS to do new rewind 4 pole.*


Why? Having rewound one motor, I feel that I want fewer slots rather than many to make the process easier; larger slots mean easier insertion. OTOH, for the motor size you are looking for, 48 slots may be the standard, but don't limit yourself at that. If 36 is available, that may be easier.
*
*


> Do you know where to find a motor like such


Look at places that buy and sell scrap metal. We have bought many motors from such a place; the standard price has been 2€ / kg. All of the motors have been perfectly working, but even if the windings were burned, that wouldn't be a problem for a rewind.


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## Stiive (Nov 22, 2008)

Siwastaja said:


> just copy the windings and reduce the number of turns in all windings by the ratio of the new voltage : old voltage, and increase the number of parallel wires by the same ratio. For example, 30 turns per slot with 3 parallel wires would become 6 turns with 15 parallel wires when decreasing nominal voltage from 400Vac to 80Vac. Then, the power could be doubled at 160Vac = 220Vdc by doubling the frequency (and rpm) at the same time.


Yup, this is the easiest/best way - not sure where your getting your info from wilkes. Rewinding this way will also work for consequent poles.


Have you tried looking for motors already wound for lower voltages? Buying two AC24L's would probably be cheaper and you'd end up with more power than trying to rewind yourself. Hit up forum member RemoteConnect.

Also, you should be searching by frame size, not HP rating - this can vary greatly. Depending on the size of your car, 132L would be the largest frame i'd suggest, perhaps 160L for a large car/ pickup / bakkie / ute / dualcab.


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## wilkes5 (Jun 1, 2012)

"Looking for a 4-pole stator frame to do a 4-pole rewind for lower voltage" sound right? 

Rewind for 120 volts (does it match the Curtis controller 1238-6501)?

You guys left out the aluminum housing, is it really needed to save weight?

What about HP rating?


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## wilkes5 (Jun 1, 2012)

Stiive said:


> Have you tried looking for motors already wound for lower voltages? Buying two AC24L's would probably be cheaper and you'd end up with more power than trying to rewind yourself. Hit up forum member RemoteConnect..


Have been looking for industrial AC motors (under the impression might be able to find one burnt out for aroun $500 then pay someone to rewind at $500. then have a $1000 motor which will out perform AC50 at $5000).


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## mizlplix (May 1, 2011)

> Rewind for 120 volts (does it match the Curtis controller 1238-6501)?


 You rewind for RMS current, not pack. We rewind for 70 VAC for the Curtis 1238. It works for us.




> You guys left out the aluminum housing, is it really needed to save weight?


 Of coarse not, but saving weight in an EV is a good thing.


Stator slot count varies with the motor diameter. The only thing to be looking for is that the slot count is divisible by 3 (the phase count) and 4 (the pole count), or you will have to skip slots to make it work out.

Miz


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## Stiive (Nov 22, 2008)

wilkes5 said:


> You guys left out the aluminum housing, is it really needed to save weight?


Saving weight is good but quite a minor part in increasing range, its more for performance. A lighter motor will be easier to mount and move around in your workshop. 
Aluminium has better thermal conductivity and with forced air should keep the motor cooler - this is the main advantage IMO.



wilkes5 said:


> "Looking for a 4-pole stator frame to do a 4-pole rewind for lower voltage" sound right?
> 
> Rewind for 120 volts (does it match the Curtis controller 1238-6501)?


Just say "Looking for a 132L frame 4-pole motor. Preferably Aluminium housing."



wilkes5 said:


> What about HP rating?


132 frame will generally be ~7.5kW-15kW rated - but this doesn't matter so much. Just ask for the frame size you want. Long stator models (132L) will have higher kW.




wilkes5 said:


> Have been looking for industrial AC motors (under the impression might be able to find one burnt out for aroun $500 then pay someone to rewind at $500. then have a $1000 motor which will out perform AC50 at $5000).


I have found plenty of 132/160 frame motors for less than $500 in pretty much brand new condition. 
Its pretty hard to find a burnt out industrial motor as name plate rating are very conservative and most industrial applications are sized to this.

A good rewind will cost more than $500 I think. An alternative is to just modify the windings to reduce the voltage which is basically free and provides basically the same result. 
The easiest, safest and best method IMO would be to buy a motor with a lower voltage winding, say 200V wye, then run in delta and at 300-400V to overspeed.


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## major (Apr 4, 2008)

Stiive said:


> Just say "Looking for a 132L frame 4-pole motor. Preferably Aluminium housing."


132L is a funny number in the USofA. Most motor shops use the NEMA standards and I don't see 132 listed and personally have never heard of that size until now. Ref: http://www.engineeringtoolbox.com/nema-electrical-motor-frame-dimensions-d_1504.html


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## Stiive (Nov 22, 2008)

major said:


> 132L is a funny number in the USofA. Most motor shops use the NEMA standards and I don't see 132 listed and personally have never heard of that size until now. Ref: http://www.engineeringtoolbox.com/nema-electrical-motor-frame-dimensions-d_1504.html



Argh, keep forgetting USA and North Korea still use imperial units.
132mm = 5 1/5" base to centre of shaft - not sure what this correlates to in NEMA.

This is the measurement IEC (international) use to define motor frame. NEMA is American standard, hence the medieval units 

Well since I know nothing about NEMA standards, I'd probably just stick with rule-of-thumb, if the motor weighs more than ~100kg (220 medieval units of mass = roughly 220 turkey legs?), its probably too big for a mid-size car


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## Siwastaja (Aug 1, 2012)

Roughly speaking:

4 poles, nominal power and torque for industrial TEFC ACIM: [2 pole motors have one "notch" higher power ratings]

132 frame, 7.5kW 50 Nm, 50 kg aluminum, 80 kg cast iron
132L frame, 11 kW 75 Nm, [don't know about weight]

160 frame, 11 kW 75 Nm, 80 kg aluminum, 110 kg cast iron
160L frame, 15 kW 100 Nm, [don't know about weight]

Note that these numbers are for a "typical" totally enclosed motor... Some motors can have very odd windings. In those cases, frames can still be good but you are on your own designing the new windings. It's easier if you have a "normal" motor.

I have not found long frames that easily... In many cases, the L frame would have optimum shape for a car, but you may need to get a normal frame if you can't find the long one.

Max torque = 3x nominal torque, for how long depends on cooling.
Max power = 3x nominal power at 3x nominal frequency... Or 9x nominal power at 3x nominal frequency and max torque combined. Again, cooling...

Now as you can see, smaller motors don't necessarily need to be aluminum framed; it's not impossible to use a 80 kg motor, it's just not wise for the power you get. Try to get a similar-weight aluminum motor instead to get 50% more power, if you just can fit it physically. 132 frame is about 10", 160 frame is about 12.5" (many DC motor users use the diameter in inches and they have good data on what diameter motors can fit in what cars).

No matter how well you cool outside the motor (the aluminum cooling ribs), it has very limited cooling activity because the heat needs to transfer from windings and rotor through insulation and air to the iron core which transfers the heat to the casing. This mechanism just can't be enough when the motor is used at higher power (even if the efficiency would remain the same), you need to push air through inside the motor to cool exposed windings directly, to cool the windings in slots from the other side too, and to cool the rotor. So, drill holes to the housing end plates, make some air ducts, add a high-pressure fan and use some kind of an air filter in line. Combine this with the outside cooling.


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## Ivansgarage (Sep 3, 2011)

wilkes5 said:


> "Looking for a 4-pole stator frame to do a 4-pole rewind for lower voltage" sound right?
> 
> Rewind for 120 volts (does it match the Curtis controller 1238-6501)?
> 
> ...


 
First off the curtis 1238 controllers, the motors should be wound for 
70 Volts (not the battery volts)


Here is somthing I posted a while back... In conclusion.. you realy want the longer stator
7 inches not the 5 inch stator (length of stator) 10-20 hp motor..

In all cases, torque is the result of force applied at a radius. In all motors, the radius increases directly with the increase in diameter of the motor, resulting in a linear increase in torque with diameter solely due to the increased radius.

The available force is directly proportional to the ((flux-carrying capability)) of the stator. So, as diameter increases and the amount of flux that can be carried in the stator increases, the torque of a motor will also increase.

Therefore, in a radial motor, torque increases with the square of diameter and also increases with additional length of the motor, stator, resulting in an overall cubic function for torque. 



Generally motors 180-440T tefc stator slots....

2 pole
1-5 hp 24 slots
7.5- 20 hp 36 slots
20-50 hp 48 slots

4 pole
1-10 hp 36 slots
15-30 hp 48 slots


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## major (Apr 4, 2008)

Ivansgarage said:


> Generally motors 180-440T tefc stator slots....


Doesn't a NEMA frame 440 motor weigh about 1500 pounds?

Poor wilkes5 isn't getting much help  



wilkes5 said:


> BUT haven't had any luck finding one. Do you know where to find a motor like such and maybe someone who can rewind? Maybe you have an opinion or differen't specs to go by when looking for a motor to EV install?


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## Ivansgarage (Sep 3, 2011)

major said:


> Doesn't a NEMA frame 440 motor weigh about 1500 pounds?
> 
> Poor wilkes5 isn't getting much help


I thought we were talking slots. Boy you guys are nit picky. lol


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## wilkes5 (Jun 1, 2012)

Stiive said:


> The easiest, safest and best method IMO would be to buy a motor with a lower voltage winding, say 200V wye, then run in delta and at 300-400V to overspeed.


interesting, but might as well be speaking Chinese to me (wye, delta?)
do you still need a longer stator motor in such setup?


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## Ivansgarage (Sep 3, 2011)

> Originally Posted by *Stiive*
> _The easiest, safest and best method IMO would be to buy a motor with a lower voltage winding, say 200V wye, then run in delta and at 300-400V to overspeed._


_Stiive 200v wye ???? 300-400v to overspeed, are you talking acim or_
_dc motor? I thought the pole count and VF controled the speed on a acim._

_Ha, learn something new every day._


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## Stiive (Nov 22, 2008)

Ivansgarage said:


> I thought we were talking slots. Boy you guys are nit picky. lol


I thought we were saying that slots doesn't matter, just rewind the motor "as-is" with fewer turns and more wires "in hand". 
Most sellers of cheap motors that you'll find on eBay wont be sympathetic to the cause and allow you to open their motor to check the number of slots before you buy. Just sayin 

Best to buy a motor by the size, pole count, and weight.



Ivansgarage said:


> _Stiive 200v wye ???? 300-400v to overspeed, are you talking acim or_
> _dc motor? I thought the pole count and VF controled the speed on a acim._
> 
> _Ha, learn something new every day._


ACIM.
200V wye will be ~115V delta. 
Running the motor 300V delta will give you ~2.6x power and speed.
Yes its frequency that controls the speed, but to maintain the same flux you need to keep the voltage/frequency the same. 115V delta will be at 60hz, therefore 300V (2.6x) will be ~160hz = 4,800 RPM for 4-pole motor.

There are typical winding voltages for industrial applications. ~220V is one in the US I think - finding this lower voltage rating in wye will mean delta voltage is even lower.



wilkes5 said:


> interesting, but might as well be speaking Chinese to me (wye, delta?)
> do you still need a longer stator motor in such setup?


Are you sure you want to rewind a motor?


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## wilkes5 (Jun 1, 2012)

Siwastaja said:


> No matter how well you cool outside the motor (the aluminum cooling ribs), it has very limited cooling activity because the heat needs to transfer from windings and rotor through insulation and air to the iron core which transfers the heat to the casing. This mechanism just can't be enough when the motor is used at higher power (even if the efficiency would remain the same), you need to push air through inside the motor to cool exposed windings directly, to cool the windings in slots from the other side too, and to cool the rotor. So, drill holes to the housing end plates, make some air ducts, add a high-pressure fan and use some kind of an air filter in line. Combine this with the outside cooling.


 
up for the challenge. the 4 gen camaro has hood scoops (which are for appearance only) and was hoping to cut it out and make some air ducks leading to the motor. might have it lead into the "holy" motor. however, it might not be pheasable due to the fact at low speeds it won't work, plus the airdynamics of the hood will be hurt? maybe a hybrid design is best, but don't see the two working with the same ducts and the fan should be turned off at high speeds?


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## Hollie Maea (Dec 9, 2009)

wilkes5 said:


> interesting, but might as well be speaking Chinese to me (wye, delta?)
> do you still need a longer stator motor in such setup?


If you are digging into the innards of an AC motor (which is abbreviation for "Three Phase AC motor...the single phase "AC" motors in your household gadgets are actually just DC series wound motors tweaked to run on single phase AC) then you'll need to learn Chinese. Start with the Wikipedia page for "Three Phase Power" and read it and follow links from it until you understand it. Trust me, you'll eventually have to know this stuff inside and out, so better to learn it now


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## wilkes5 (Jun 1, 2012)

Stiive said:


> Are you sure you want to rewind a motor?


Want a wind/solar off grid ranch/castle with a great electric sports car and eat vegetarian. 

Need to find an AC motor to pair with one of the used Curtis controllers. Trying to save money and recycle the old industrial motors at the same time (motor$500/rewind$800/curtis$750). Realize industrial AC need to be rewound and willing to learn (Ivan has some good "how to" stuff). However, don't mind to pay to pay someone to rewind if it becomes too difficult for me. So, would like to have the motor specs before calling the place to ask for one, you know?

option 1
"20 hp AC motor with longer stator (7 inches) and aluminum housing. It needs 48 slots. It needs to be able to be rewound to 70 volts"

option 2 
"Looking for a 132L frame 4-pole motor. Preferably Aluminium housing." 
(but maybe replace 132L with 160L because the car which is being converted weights aroun 3300lbs).

option 3
Best to buy a motor by the size, pole count, and weight. 
(size? pole count? weight?) 

option 4
Buying two AC24L's would probably be cheaper and you'd end up with more power than trying to rewind yourself. Hit up forum member RemoteConnect.

*which option is best?*


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## wilkes5 (Jun 1, 2012)

Ounce the motor spec is nailed, THEN worry about the rewind....


option 1
Ivan seems to do the typical rewind and has pictures with details online. 
A+


option 2
Siwastaja: copy the windings and reduce the number of turns in all windings by the ratio of the new voltage : old voltage, and increase the number of parallel wires by the same ratio. For example, 30 turns per slot with 3 parallel wires would become 6 turns with 15 parallel wires when decreasing nominal voltage from 400Vac to 80Vac. Then, the power could be doubled at 160Vac = 220Vdc by doubling the frequency (and rpm) at the same time.

option 3
cut wires in the winding to reduce the voltage

*which is best?* (maybe keep in mind, still have the option to take it to a rewind shop if it is too hard for me)


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## Remotecontact (Mar 16, 2010)

Hey guys.

You can find my AC24LS motors here: 

http://www.ebay.com/itm/Azure-Dynam...345?pt=LH_DefaultDomain_0&hash=item2578482a81

Quantity discounts available!


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## tomofreno (Mar 3, 2009)

Stiive said:


> ACIM.
> 200V wye will be ~115V delta.
> Running the motor 300V delta will give you ~2.6x power and speed.
> Yes its frequency that controls the speed, but to maintain the same flux you need to keep the voltage/frequency the same. 115V delta will be at 60hz, therefore 300V (2.6x) will be ~160hz = 4,800 RPM for 4-pole motor.
> ...


 This would make it very easy...but you then need a 300V motor controller and those generally cost considerably more than the lower voltage Curtis AC controllers.


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## wilkes5 (Jun 1, 2012)

Stiive said:


> Have you tried looking for motors already wound for lower voltages? Buying two AC24L's would probably be cheaper and you'd end up with more power than trying to rewind yourself. Hit up forum member RemoteConnect.


hoping the AC24L is made in USA? 
best online resource for combining two motors like such (AC24L)?
can both be ran off the Curtis 1238?


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## Ivansgarage (Sep 3, 2011)

wilkes5 said:


> hoping the AC24L is made in USA?
> best online resource for combining two motors like such (AC24L)?
> can both be ran off the Curtis 1238?


can both be ran off the Curtis 1238

No each motor needs an encoder and it won't work with
a single 1238 controller. HPEV has a dual motor car, with two
controllers.

The more we read and think, the deeper we get.

--


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## major (Apr 4, 2008)

wilkes5 said:


> best online resource for combining two motors like such (AC24L)?


Maybe Farfle? http://www.diyelectriccar.com/forums/showthread.php?t=82369


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## wilkes5 (Jun 1, 2012)

OK, back to the top (love circles)...


Looking for 

*1--20 hp maybe with a vf rating, it would have a longer stator, about*
*seven inches in lenght. Yes you want the longer stator.*

*2--2 pole 3450 rpm, motors are likely to have more back iron.*

*3-- 208, 220, 440 volt, or just 208, 220*

*4--aluminum housing, motor weight would be about 225 lbs*

*5--C face (pump motors)*

*6--totaly enclosed fan over, that gives you a tail shaft for the encodder.*

*7--should have 48 SLOTS to do new rewind 4 pole.*

Can anybody provide a phone number to a motor shop (or a web address to a specific motor for sale...fea bay, etc.) which sells motors with the above specs?


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## PStechPaul (May 1, 2012)

I think you may do better with a four pole, but if you are rewinding, it may not make much difference. But it should be rewound as four pole (or even 6 or 8), if you plan to overclock. 3600 RPM is pretty safe, and maybe up to 4000 or 5000, but there may be issues with bearings and balance.

36 slots seems more common and should be suitable for four and six pole. For three phase, 36/3 = 12, which is divisible by 2, 4, 6, and 12. OTOH, 24/3 = 8, which is divisible by 2, 4, and 8. More slots may provide more flexibility for rewinding. 48/3 = 16, for 2, 4, 8, and 16 pole. But 6 pole (1200 RPM) may be a good choice for higher torque and the ability to overclock to 3x (3600 RPM) or 4x (4800 RPM).

Here are some links:

http://hmin.tripod.com/als/ccs/docs/pdf/150-br008.pdf
http://what-when-how.com/electric-motors/stator-winding-design-considerations-electric-motors/

Here are some motors that might work for you:
http://www.ebay.com/itm/360056080977
http://www.ebay.com/itm/130728252640
http://www.ebay.com/itm/180861740470
http://www.ebay.com/itm/281020013127
http://www.ebay.com/itm/160702392249
http://www.ebay.com/itm/200835922090
http://www.ebay.com/itm/350452257632
http://www.ebay.com/itm/150864025707
http://www.ebay.com/itm/400037377319
http://www.ebay.com/itm/200854894737
http://www.ebay.com/itm/140747524695
http://www.ebay.com/itm/200471861183
http://www.ebay.com/itm/181038522620

The last item seemed the best deal but I think it has been sold.

You can search for electric motor repair and rewinding shops in your area. Here are some in MD where I am:
http://langeelectric.com/about/
http://emrco.com/rewinding.php
http://www.robertselectricmotors.com/
http://www.apprep.com/


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## wilkes5 (Jun 1, 2012)

PStechPaul said:


> But 6 pole (1200 RPM) may be a good choice for higher torque and the ability to overclock to 3x (3600 RPM) or 4x (4800 RPM).


 
Just to confirm, for a 6 pole you need 36 slots. "36 slots seems more common and should be suitable for four and six pole. For three phase, 36/3 = 12, which is divisible by 2, 4, 6, and 12". And a motor like such can be ran off curtis 1238? 

Does anyone else agree with the 6 pole? Yes or no is fine, no need to explain. If all else fails, just fall back on

*1--20 hp maybe with a vf rating, it would have a longer stator, about
seven inches in lenght. Yes you want the longer stator.*
*2--2 pole 3450 rpm, motors are likely to have more back iron.*
*3-- 208, 220, 440 volt, or just 208, 220*
*4--aluminum housing, motor weight would be about 225 lbs*
*5--C face (pump motors)*
*6--totaly enclosed fan over, that gives you a tail shaft for the encodder.*
*7--should have 48 SLOTS to do new rewind 4 pole.*

When buying online, are you able to tell how many slots the motor has? Numbers to some local shops in the USA would be helpful in trying to save $ if you wanted to get a burnt out one.


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## Ivansgarage (Sep 3, 2011)

wilkes5 said:


> Just to confirm, for a 6 pole you need 36 slots. "36 slots seems more common and should be suitable for four and six pole. For three phase, 36/3 = 12, which is divisible by 2, 4, 6, and 12". And a motor like such can be ran off curtis 1238?
> 
> Does anyone else agree with the 6 pole? Yes or no is fine, no need to explain. If all else fails, just fall back on
> 
> ...


6 pole is NOT more common, 2 and 4 I have never heard of one EV manufacturer ever use a 6 pole, you get very little extra rorque, and
a greater rpm loss.

10 to 15 hp 36 slot a 20hp 48 slot most common..

--


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## major (Apr 4, 2008)

wilkes5 said:


> And a motor like such can be ran off curtis 1238?


And that is a whole other question. Answer is maybe. The Curtis controller must be tuned to the particular motor. To do this you need a program or programmer. That will cost you. You also need an encoder on the motor and a thermal sensor. And you also need to know what you're doing (no offense intended).

I have yet to see anyone use a Curtis 1238 controller with a motor other than an HPEVS tuned by them. O.K. One exception. Kevin in Topeka. And he is in the motor business and likely had help from Baldor and maybe Curtis. Undoubtedly Curtis is used by OEMs with other motors for industrial vehicles and such and engineering support would be available. But an individual such as yourself should not count on any help unless you purchase from a reputable dealer with a clear understanding beforehand.


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## Ivansgarage (Sep 3, 2011)

major said:


> And that is a whole other question. Answer is maybe. The Curtis controller must be tuned to the particular motor. To do this you need a program or programmer. That will cost you. You also need an encoder on the motor and a thermal sensor. And you also need to know what you're doing (no offense intended).
> 
> I have yet to see anyone use a Curtis 1238 controller with a motor other than an HPEVS tuned by them. O.K. One exception. Kevin in Topeka. And he is in the motor business and likely had help from Baldor and maybe Curtis. Undoubtedly Curtis is used by OEMs with other motors for industrial vehicles and such and engineering support would be available. But an individual such as yourself should not count on any help unless you purchase from a reputable dealer with a clear understanding beforehand.


program or programmer FREE software on web, someplace..


I think he could count on help. Thats what Miz and I are about.

Thermistor .15 cents
encoder 130.00 bucks
--


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## wilkes5 (Jun 1, 2012)

PStechPaul said:


> http://langeelectric.com/about/
> http://emrco.com/rewinding.php
> http://www.robertselectricmotors.com/
> http://www.apprep.com/


 
going to be calling each to see what is available.

but important to nail down the motor specs before buying no, and the whole thread is filled with differen't opinions and myself has no clue what to listen to, so might just stick to the specs mentoined in the opening.


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## major (Apr 4, 2008)

Ivansgarage said:


> program or programmer FREE software on web, someplace..


You sure? Can you find that? And have you tuned a rewind to the Curtis? I'd love to see your parameter list.


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## major (Apr 4, 2008)

Ivansgarage said:


> encoder 130.00 bucks
> --


What is the cost to machine the shaft and end bell for the encoder mount?


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## Ivansgarage (Sep 3, 2011)

major said:


> What is the cost to machine the shaft and end bell for the encoder mount?


I have a lathe, didn't cost anything. and with a tefv motor there
is a fan on it so the end bell is allready flat to mount the encoder.
A motor rotor is easy to chuck up in a lathe, would think a machine
shop should only take a hour or two. Took me a hour.

Hopefully we should optomize the motor bye end of week..

Miz has had a lot of family activity stuf.

-


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## Ivansgarage (Sep 3, 2011)

major said:


> You sure? Can you find that? And have you tuned a rewind to the Curtis? I'd love to see your parameter list.


Major don't you have a curtis controller, thought you where into AC.

Here is Mizs post on curtis stuff.
http://ivanbennett.com/forum/index.php?topic=13.0

-


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## major (Apr 4, 2008)

Ivansgarage said:


> Major don't you have a curtis controller, thought you where into AC.
> -


Yes Ivan, I have several Curtis controllers in the lab. Until now, they have all been used with HPEVS motors. But now I have a different motor and want to try the Curtis on it. So I am interested in how to do that and can't get straight answers from anybody here.

As far as that free Curtis software available on the web, I thought that was taken down a while back and is no longer available. You say it is there, please provide link. Otherwise guys like wilkes5 should plan on shelling out about $600.

These are all fair questions about this DIY AC motor rewind which need to be addressed. Right now I see about $1000 in encoder, encoder mount machining and programmer. And I do not see a valid source for assistance. I realize that you and Miz have good intents, but fact is that you have not yet done the deed and cannot guarantee results.

I hope you succeed and can provide me a good example to follow next week. 



> Here is Mizs post on curtis stuff.
> http://ivanbennett.com/forum/index.php?topic=13.0


A quote from the motor tuning page


> NOTE: I will be doing this test soon on our new motor. I will change this section after I have something to write about.
> 
> Miz


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## Ivansgarage (Sep 3, 2011)

major said:


> As far as that free Curtis software available on the web, I thought that was taken down a while back and is no longer available. You say it is there, please provide link. Otherwise guys like wilkes5 should plan on shelling out about $600.


Major can not post link to public.. email

Did you need it.

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## major (Apr 4, 2008)

Ivansgarage said:


> Major can not post link to public.. email
> 
> Did you need it.
> 
> -


Yes, please send it via PM.


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## wilkes5 (Jun 1, 2012)

thanks for everyone's help. but going to go with the original specs mentioned in the opening. best to just "walk in" a local shop and find a burn out for cheap. Again, it wouldn't even happen if it wasn't for Ivan and his resources. A+ for the DIY community. 

however, if someone could post pictures on how to just "cut" the winding to achieve a lesser voltage, it might be easier to do than rewind one from scratch. 

Major, you bring up good points, but it seems negative most of the time. Reminds me of myself when telling people it's bad to buy from China.


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## Ivansgarage (Sep 3, 2011)

wilkes5 said:


> however, if someone could post pictures on how to just "cut" the winding to achieve a lesser voltage, it might be easier to do than rewind one from scratch.


Wilkes cutting and reconnecting might lower the voltage, here we go, But
read this.

http://ivanbennett.com/forum/index.php?topic=15.0


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## wilkes5 (Jun 1, 2012)

Ivan, with all the help you have provided so far, was really asking the others who brought up the technique. Appreciate your work, and don't mean to cloud it in any way. A straight forward answer to EV conversion with industrial AC motors. Anyone else putting in the time to organize and state more clearly?


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## major (Apr 4, 2008)

wilkes5 said:


> Major, you bring up good points, but it seems negative most of the time.


Call it realistic


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## wilkes5 (Jun 1, 2012)

Hopefully the thread provides some good info for newbies (or persons who don't have the knowledge about electric motors) about how to convert your standard industrial AC to work in an EV. Thinking total price to be around 2500 tops. Which compared to the AC50 combo of around 5000. You can have a motor for half the price (possibly with more performance?) with a little elbow grease. Not to mention, believe the Curtis controller is one of the best for "made in USA" out of the list of controllers (unless you have the knowledge for DIY, whoopie pie). Plus, recycling the used AC industrial motors saves, right (plus most seem to be made in USA). It's just a win win for the what's "right" it seems like. 

Now if only a good US manufacturer of lithium batteries exsisted, hummm.


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## major (Apr 4, 2008)

wilkes5 said:


> Now if only a good US manufacturer of lithium batteries exsisted, hummm.


EnerDel makes an excellent product in Indianapolis. http://www.enerdel.com/


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## Ziggythewiz (May 16, 2010)

Hey, the website's even still in English!


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## Siwastaja (Aug 1, 2012)

wilkes5 said:


> thanks for everyone's help. but going to go with the original specs mentioned in the opening.


No, don't get a 2-pole motor. Get a 4-pole or maybe 6-pole. Don't specify the number of stator slots, it's irrelevant whether it's 36 or 48.



> however, if someone could post pictures on how to just "cut" the winding to achieve a lesser voltage, it might be easier to do than rewind one from scratch.


Yes it is very easy, it took less than an hour to actually do it. See this post: http://www.diyelectriccar.com/forums/showpost.php?p=329129&postcount=112

But as a disclaimer, we have only tested this with no load so far.

And, this mod may not be enough for a 400 V motor. Get one which is 230V in delta. Or even better yet, 230V in wye.

This mod works with 4-pole motors by halving the nominal voltage. It is not possible with 2-pole motors.
http://www.diyelectriccar.com/forums/showpost.php?p=329129&postcount=112


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## tomofreno (Mar 3, 2009)

wilkes5 said:


> Thinking total price to be around 2500 tops. Which compared to the AC50 combo of around 5000.


 The AC50 is typically a bit over $4k, Ethos Electric Vehicles lists it for $3.8k. And that includes the motor controller, wiring harness, and gauge. You can likely find a suitable used AC motor in good condition for around $500, so maybe save $1k or a bit more for overall motor/controller depending on whether you do the rewinding or pay someone else to do it. But that assumes you know enough to select a good candidate motor. Btw, most of the info on this thread (and much more that is not on it) is in other threads that have been around for years, e.g. at this site:
http://www.aeva.asn.au/
You just have to search.


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## wilkes5 (Jun 1, 2012)

major said:


> EnerDel makes an excellent product in Indianapolis. http://www.enerdel.com/


good job major.

have you heard of molicel batteries also (believe based out of tiawan/canada) maybe another brand to consider?

going to call EnerDel and have someone explain the manufacturing process (where raw materials are sourced/what chemicals used/where the manufacturing takes place). from my experience, you really need to ask in depth questions, or might be getting something which isn't really made in USA.


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## wilkes5 (Jun 1, 2012)

Siwastaja said:


> No, don't get a 2-pole motor. Get a 4-pole or maybe 6-pole. Don't specify the number of stator slots, it's irrelevant whether it's 36 or 48.
> 
> Yes it is very easy, it took less than an hour to actually do it. See this post: http://www.diyelectriccar.com/forums/showpost.php?p=329129&postcount=112
> 
> ...


took a look...could be a valid technique (considering it hasn't seen a load plus do any successful conversions using such technique exsist). it seems a little difficult to picture what is actually happening in the picture (maybe an easy to follow real life picture of the windings being cut to follow along with a hypothetical picture?). also, beginners might want to stick with examples which have been done to success, with access to real pictures and people to talk to. does such exsist for the "cut and solder" technique? you would be one to talk to, what about real pictures and diagrams?


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## wilkes5 (Jun 1, 2012)

tomofreno said:


> You just have to search.


nice website. a good wish for me to attend one day.

pretty tired of searching. can't even find a pair of jeans which fit right (with the other criteria of eco friendly and made in.....). 

if had the money, would just offer a good person (someone who believes in doing right) in the DIY community to build me a car using all equipment made in GOOD countries. boom, 20000 bucks, find out where every ounce of metal in the equipment comes from and make sure it's manufactured the "right way". but wouldn't even have to ask, the person would know to do such and cut corners the good way (like recycling a used AC industiral for rewind).


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## Siwastaja (Aug 1, 2012)

wilkes5 said:


> took a look...could be a valid technique (considering it hasn't seen a load plus do any successful conversions using such technique exsist). it seems a little difficult to picture what is actually happening in the picture (maybe an easy to follow real life picture of the windings being cut to follow along with a hypothetical picture?). also, beginners might want to stick with examples which have been done to success, with access to real pictures and people to talk to. does such exsist for the "cut and solder" technique? you would be one to talk to, what about real pictures and diagrams?


This is *DIY*electriccar... Of course building, rewinding or rewiring/modding motors is not for beginners. You need to gather information, make your decisions, find suitable parts, then try your theory in practice, get feedback from your results, etc.

For an easy solution, just buy an EV motor+controller kit. It might also be the cheapest solution in the long run. I have already spent about $1500 for stuff needed for rewinding (magnet wire, insulation materials, etc.).

Anyway, there are results of using rewound industrial AC motors and they work just fine. No one has been able to show how rewiring series windings to parallel would pose any kind of real problem. Resistance changes from 2R to ½R so I^2R losses stay exactly the same with 2I. 

(Compare to first driving two 12V lightbulbs from a 24V source in series, and then changing them to parallel and driving them from 12V -- same results, same power).

The only possible problem anyone has been able to show in parallel rewiring would be current sharing between the pole pairs. Series connection ensures same current in both windings, but in parallel connection, impedance differences between the branches could result in one pole pair heating up more than the other. This needs to be evaluated in practice.

These are all case-by-case projects that need some commitment, testing, failures and finally, hopefully, may lead to good results; but in any case, they lead to higher level of knowledge.

Rewire modding is quick to do, but you still need to install the motor to a car with a proper coupler and buy (or build) and configure an AC controller.

I'm giving out the information what we are currently working with but we have other things to do at the same time, so the projects go on pretty slowly. Furthermore, our first conversion will be using a fully rewound motor, so the modded motor won't see the daylight right now. We'll probably use it in another conversion.


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## tomofreno (Mar 3, 2009)

Siwastaja said:


> Anyway, there are results of using rewound industrial AC motors and they work just fine. No one has been able to show how rewiring series windings to parallel would pose any kind of real problem.


 This is standard stuff described in electric motor shop manuals. People been doing it for generations.


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## Ivansgarage (Sep 3, 2011)

tomofreno said:


> This is standard stuff described in electric motor shop manuals. People been doing it for generations.


Tom, You forgot to add the But!

Motors designed for electric vehicles (there is no book) have to handle 3 to 4 time the current than a stock industrial motor (winding). Most 10hp, 15hp and 20hp industrial motors would have a max current rating of 20 to 40 amps max continuous.

So the question is? will the modified winding, ie..for voltage handle
the higher amps (current) changing to a lower voltage will increase the current.


-


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## Siwastaja (Aug 1, 2012)

Yes, the parallel wires will handle the increased current. Current per wire, or current per area (mm^2 or circular mils) does NOT increase. Of course you need to provide thicker input wires, but that's all.

So by halving the voltage rating, the current rating doubles because of doubled number of in-hand wires. For example, 3 parallel "in hand" strands in two series windings become 6 parallel "in hand" strands when the windings are in parallel. Changing two series windings to parallel will drop the resistance to 1/4: R -> 0.25R. At the same time, current doubles: I -> 2I. Because losses are I^2 * R, the new losses will be (2I)^2 * 0.25 R = I^2 * R -- no change.

Halving the voltage will double the current for the same power.

Overclocking and overvoltaging will not increase current. This is how you do it. Use higher rpm and use reduction gearing.

Increasing TORQUE over the nameplate value will increase current, though. This is problematic because the losses are I*^2*R. That's why you do it by increasing voltage, frequency and RPM. Anyway, industrial motors should be fine at 150% current without increased cooling for ages, and you _can_ increase torque _temporarily_ by increasing current up to 3x, but this will be a peak value for a few seconds.

REMEMBER! P = U * I.

This is not rocket science.

But this forum has a very strong skepticism toward any basic knowledge, facts and experience coming outside the EV community. That's fine, but remember that EV's are a pretty novel thing so outside information is _needed_. An electric motor is an electric motor, whether it's in a car or a train or in a factory. Laws of physics and electronics apply in EV's, too.

Talking about current makes absolutely no sense if you don't talk about voltage, too (and vice versa). A 1000V motor, for example, won't need high current even if it is in an EV. P = U * I. Remember this.


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## QuietCar (Jan 3, 2013)

From what I experience at work, firefighters are really concerned by the danger of extremely high currents and voltages contained in today's electric cars.

Their ability to give up this current quickly is a basic need for their operation.

Extremely high voltage is not. 

It is kinda like using a .300 Win Mag on deer when a .3030 would have done the same job without all of the possible "over shoot".


*Where is the optimum voltage point for an electric road car?*

I know from reading, your DIY cars have cut-off switches, fuses and such but *does anyone have those orange pulled out "cut loops" for first responders? * 

THX QC


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## major (Apr 4, 2008)

QuietCar said:


> From what I experience at work, firefighters are really concerned by the danger of extremely high currents and voltages contained in today's electric cars.
> 
> Their ability to give up this current quickly is a basic need for their operation.
> 
> ...


Hi Quiet,

I think you should have started a dedicated thread for this topic. It doesn't have much to do with finding a motor 

Perhaps you could do that and post more information about the cut loop and maybe a photo.

Welcome aboard,

major


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## TEV (Nov 25, 2011)

major said:


> Hi Quiet,
> 
> I think you should have started a dedicated thread for this topic. It doesn't have much to do with finding a motor
> 
> ...


No need to start a new thread, it's all ready started 

http://www.diyelectriccar.com/forums/showthread.php/emergency-responder-warnings-57522.html


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## wilkes5 (Jun 1, 2012)

Siwastaja said:


> Yes, the parallel wires will handle the increased current. Current per wire, or current per area (mm^2 or circular mils) does NOT increase. Of course you need to provide thicker input wires, but that's all.
> 
> So by halving the voltage rating, the current rating doubles because of doubled number of in-hand wires. For example, 3 parallel "in hand" strands in two series windings become 6 parallel "in hand" strands when the windings are in parallel. Changing two series windings to parallel will drop the resistance to 1/4: R -> 0.25R. At the same time, current doubles: I -> 2I. Because losses are I^2 * R, the new losses will be (2I)^2 * 0.25 R = I^2 * R -- no change.
> .


detailed information like such about the technique to "cut and parallel" the windings seems to only validate the technique for using a industrial AC motor for EV. do you have a website about your projects? 

again, for me, going to give the standard rewind method a shot because of the available resource of help. if help like such (step by step pictures of "cut and parallel" where available, along with poeple like Siwastaja who would lend a hand, then it would be a debate for me on which would be easier. some might perfer one way, and others another?


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## Siwastaja (Aug 1, 2012)

wilkes5 said:


> detailed information like such about the technique to "cut and parallel" the windings seems to only validate the technique for using a industrial AC motor for EV. do you have a website about your projects?
> 
> again, for me, going to give the standard rewind method a shot because of the available resource of help. if help like such (step by step pictures of "cut and parallel" where available, along with poeple like Siwastaja who would lend a hand, then it would be a debate for me on which would be easier. some might perfer one way, and others another?


We don't have a website, but you might want to read this thread: 

http://www.diyelectriccar.com/forum...nduction-motor-rewinding-questions-77776.html

As for reconfiguration, it's just so simple that it's a no-brainer. It just happened one night or morning, can't remember, but we didn't even think about taking pictures... The motors always look about the same inside anyway. There are three connections that are cut and soldered as I show in that thread.

But I think the limitation is that reducing the voltage by factor 2 is not enough; we went for factor 5 in our rewind. But anyway, halving the voltage requirement is so much better than using a stock motor. A 500-600V battery pack is not nice but it is doable; 1000-1200V is practically impossible.


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## major (Apr 4, 2008)

Siwastaja said:


> For an easy solution, just buy an EV motor+controller kit. It might also be the cheapest solution in the long run. I have already spent about $1500 for stuff needed for rewinding (magnet wire, insulation materials, etc.).


I notice that Ivan has commented about your $1500 cost on his forum. He claims it should be less than $500. It would be nice if he'd post responses like that here. But anyway, Siwastaja, how many pounds of copper wire did you need to buy? 

Thanks,

major


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## tomofreno (Mar 3, 2009)

Ivansgarage said:


> Tom, You forgot to add the But!
> 
> Motors designed for electric vehicles (there is no book) have to handle 3 to 4 time the current than a stock industrial motor (winding). Most 10hp, 15hp and 20hp industrial motors would have a max current rating of 20 to 40 amps max continuous.
> 
> ...


 Well, I referred specifically to paralleling windings to reduce resistance and operating voltage, not to rewinding. 

But regarding your comment, typically in order to lower the operating voltage and maintain the same air gap flux you have to decrease the winding resistance to maintain the same stator amp-turns or MMF, which you do by increasing the circular mils (Edit: square of the wire diameter), or cross sectional area of the wire. 

For example, from Electric Motor Repair, by Robert Rosenberg, 2nd Ed. 1970, pg 32 (first written in 1941): 



> Rewinding for a Change of Voltage…
> RULE 1: New turns = (new voltage/original voltage)*original turns per coil
> 
> RULE 2: New c.m. area = (original voltage/new voltage)*original c.m. area


 Are you saying that you use a larger circular mil increase and larger number of turns (to obtain the same resistance) than these rules state? I would guess that usually there would not be room in the slots to do so. By decreasing the turns and increasing the circular mils by the above rules you end up with the same amount (weight) of copper in the slots, so it has the same power handling capability, just at different current and voltage.

Edit: I think most industrial AC motors will be designed to operate at rated full load with a comfortable margin below their maximum specific electric and magnetic loadings. They have enough heat capacity and cooling to accommodate doubling or tripling the specific electrical loading for short periods without overheating, but require a blower to cool the rotor if run at significantly higher currents continuously (not an option with TEFC type motors). So I don't think a rewound motor will over heat during typical driving as long as a large enough motor for the application is chosen. I'm sure major will correct me if I am wrong.


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## Siwastaja (Aug 1, 2012)

major said:


> I notice that Ivan has commented about your $1500 cost on his forum. He claims it should be less than $500. It would be nice if he'd post responses like that here. But anyway, Siwastaja, how many pounds of copper wire did you need to buy?
> 
> Thanks,
> 
> major


That's clearly taken out of context . It was just how much I have invested to get started, as an example that you may end up using money more than you first thought... 

But I think it will be enough for nearly 10 motors! So, per motor material cost for full rewind is about $100 - $200 depending on material source and motor size. Add $200 for the "donor" motor. But when you sell the scrap copper, you may get about $30-50 back.

I made the mistake of first buying 22 kg of wire that is clearly too thick. Harder to wind and I don't know about skin/proximity effect related problems. Had to buy another 22 kg of thinner wire then. So now I have a lot of high quality 1.2mm(dia) enammel wire I probably do nothing with. But maybe some _very_ large motors could be wound with this.

The real cost comes from the labor, not the materials. DIYing a rewind _can_ be very cheap _if_ you could get small amounts of materials somewhere for a good price, and you do it right the first time.


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## PStechPaul (May 1, 2012)

Just for reference, your 1.2 mm wire is #13 AWG. Yeah, that's hard to work with. When I first thought about rewinding motors, I was going to make them run on 12V, and I bought some #10 AWG. Not a good idea. But I have used it for some transformers, so not a total waste.

I just searched eBay, and found that the price of magnet wire is something like $7 to $15 per pound (buy it now). I was surprised to find some magnet wire made of aluminum! It's from a place in Canada and made in China. 
http://www.ebay.com/itm/1720-ft-22-...et-wire-insulated-enameled-wire-/130828976523

Here's what appears to be a good source of various gauges for about $10/lb (and free shipping):
http://www.ebay.com/itm/Magnet-Wire...00ft-200C-Magnetic-Coil-Winding-/251131333844

They have a pretty good FAQ on their website:
http://www.temcocontent.com/mwfaq.html


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## tomofreno (Mar 3, 2009)

Siwastaja said:


> That's clearly taken out of context . It was just how much I have invested to get started, as an example that you may end up using money more than you first thought...
> 
> But I think it will be enough for nearly 10 motors! So, per motor material cost for full rewind is about $100 - $200 depending on material source and motor size. Add $200 for the "donor" motor. But when you sell the scrap copper, you may get about $30-50 back.
> 
> ...


 On the other hand, many times this is the way it goes in diy, mistakes are made, especially during first attempts...I'd wager the true cost of conversions is significantly more than what you see posted on the evalbum and in the garage here. Oh that part, well uh, I didn't use it so it doesn't count toward conversion cost...


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