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Finding a motor on a budget

301K views 175 replies 63 participants last post by  Banks1234 
#1 · (Edited)
So here is what I learned about motors from this site. I wanted to post a quick reference so newbs (like myself) do not have to sort through the sticky page.

When looking for a forklift motor:
Get a series wound motor because they have very high torque and handle abuse (over volting) a lot better.
Know the difference between a Spex motor and a Series wound.
When dealing with series wound forklift motors go for higher voltage. (36V may require advanced timing.)
Hp does not directly represent torque (although it does have a factor in its equation).
Get a class H insulation if possible (makes your motor last longer)
Get a motor around 150lbs (Wouldn't risk a motor that's too light, it won't have the oomph you need. a few extra pounds is A-o.k. but a significant amount of extra pounds limits your range)
Get one with a male shaft
A keyed shaft is easier to work with but you can still work with a spline shaft
Try and get the coupler that goes on to your motor when you buy it/rip it out (saves you $$ and time)
When looking for a different motor:
Ac is not the way to go for your first conversion (or do i just have low expectations of myself?)
You can tell if a motor is AC if it is a 1 phase or 3 phase motor
Pancake motors are usually not good candidates for car conversions. (Yeah you saw the one on ebay. They overheat easily)
Golfcart motors are seldom powerful enough for a conversion
Motors specifically made for EV conversions are the best but its gonna cost you.
You do have to look at many factor such as volts, amps (which gets you Hp). Torque is nice to know. Continuous Hp. So many factors!!!
"HP is HP Electric motors and gas engines are rated differently w/r/t HP. And they have different torque curves. But one HP from an electric motor shaft is exactly the same as one HP from a gas engine shaft at the same RPM :)"- Major
If there is any more helpful hints I'll be happy to add them
 
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#44 ·
A1 and A2 are the rotor connections and S1 and S2 are the (serial) field connections.
So if you connect A1 to the battery and S1 to A2, it should run one way if you connect S2 to the other battery pole, and the other way with S2-A2 interconnected and S1 on the battery.
If that trick doesn't work, I fear there is some massive short cirquit in the field winding or in the wiring.
 
#59 ·
In the jargon of electricians "S" is for "Stator"

Electronics technicians would label it "F" for "Field".

I really wish electronic technicians and electricians could standardize symbols and names better

Im an industrial electrician so I have to deal with both sets and it irritates the hell out of me sometimes

Its almost like speaking two different languages that are distantly related, like Italian and Latin.


These two sentences mean exactly the same thing

" I need the in-line reactor in series with the stator"

" I need the induction coil in series with the field "

And it doesn't stop there

"E" is "V"

Snubber is a filter

"Lagging Power Factor" is "Negative Phase Angle"

" Contactor " is " Power Relay"

And I swear to God I feel like strangling the son of a bitch who came up with some of the electrical terms the computer nerds use.
( So now its Italian, Latin and Ebonics.)
 
#47 ·
Forklifts:

It is seldom the motor that retires a forklift for good, it's the battery + one other problem, often the transmission or hyd pump or circuit board. The battery is the most expensive part, often over $5k. I've never had a motor failure, but other issues.

I feel guiltly, but I have perhaps "given" away 3 forklifts in my life. Scrap value.

Look on Craigslist, a busted electric forklift is often dirt cheap after you subtract the resale value of the battery. The batteries are often over 2000lb, mostly lead. Scrap batteries are 30 cents US a pound, so over $600, and the lift can be had for $500. What's the catch? A forklift weighs 4500+ lbs. You must pick it up in person.
 
#48 ·
Forklifts:

The battery is the most expensive part, often over $5k.
(....)

A busted electric forklift is often dirt cheap after you subtract the resale value of the battery. The batteries are often over 2000lb, mostly lead. Scrap batteries are 30 cents US a pound, so over $600, and the lift can be had for $500. What's the catch? A forklift weighs 4500+ lbs. You must pick it up in person.
You should get them in Holland, I pay 1,8k€ (roughly 1,4k$) for a 24v set of 700AH tubular batteries (and real good ones, I bought them in 2000 and they still have approx. 90% of their initial storage capacity by daily use).
So for a 48v forklift that would make 2,8k.

Batteries are seldom really dead. If you buy the forklift with batteries that need replacement you stilll would get a couple of miles out of them after thoroughly loading (and refilling with distilled water) so if you can get it anywhere in the neighbourhood you could still drive it to your garage if you´re lucky.
Nevertheless I would still recommend paying the firm that scraps the thing to unmount the motor at a reasonable price so you are not left with 4100 tons of scrap, and they can still sell it for roughly the same price so everybody happy.
I don´t now how regulations are in the US but here lead-acid batteries are virtually worthless, as nowadays they only accept empty ones that are cleaned from any trace of sulphuric acid and you have to dispose of that acid in a legal way so any profit on the lead is eveporated on advance.
 
#50 ·
I have a shifter that can shift two poles at a time (I want to keep it simple) . If I cant just switch neg an pos , how should I hook up this switch ? A2 switches or S1 ? Will A1 get pos and not get switched ? Can I just switch S1 an S2 between a pos an neg and then just let A1 stay pos an A2 stay neg ? Can the motor be sent to a motor shop an made to just run in series so I can just swap the poles ?
Electrical wiring Wire Electrical supply Cable Technology
 
#51 ·
I have a shifter that can shift two poles at a time (I want to keep it simple) . If I cant just switch neg an pos , how should I hook up this switch ? A2 switches or S1 ? Will A1 get pos and not get switched ? Can I just switch S1 an S2 between a pos an neg and then just let A1 stay pos an A2 stay neg ? Can the motor be sent to a motor shop an made to just run in series so I can just swap the poles ?
Rich or poor, if you want reverse, I think you should invest in a controller that has reverse capability.
 
#56 ·
Controller was bad and I just needed to switch the S1 an S2 to get reverse , switch the field not the rotor . The utility cart the motor came from had a tool box with engines on it an could push a car every night . I seen it do that before he stop paying his taxes . It can go to the body shop now that I see the basic parts work .
 
#60 ·
The industry standard for marking the terminals on DC motors used in forklifts, industrial utility vehicles and golf carts in the United States was and still is, I believe, as follows:

A for Armature (connected internally through the brushes),

S for Series field coils,

F for Shunt or Separately Excited field coils.
 
#64 ·
I work for a large airline and when we scrap electric vehicles I assure all of you it's never because the motor is bad.
If its old the cost of new hoses fork blades paint seat tires brakes and the kicker a $5000 to $6000 battery is the reason to scrap.
Last month we sent 8 electric pickers to scrap because it was part of the city contract with the building, go figure!
I have a 9 inch dc advance they threw away with under 100 hrs on it because someone didn't tighten the set screw on the shaft key ill just weld the adapter on or redo the shaft if i ever get a project.
Why toss a 1000 motor cause time is money and. Sending people far away and paying for hotels out costs parts.
Fork lift motors are good also airport belt loaders and bag tugs if they are electric are good most of the belt loaders and bag tugs use dc advance 9 inch motors
http://gsemarket.com/index.htm
Used stuff some times sells for less than scrap value on this site
It has to do with tax depreciating equipment to nothing being better than scrapping it without proff of 0 value
Happy hunting
 
#66 ·
Is a 50kw motor big enough, 67,000HP to drive an electric car?
That should be 67 HP not 67,000. I think you will need to supply more info to answer your question properly. Depending on many other factors, it might or might not be. 50kw is enough to move a small car, but a power number alone is not enough. Example, I have a forklift motor that is only rated for 10kw, but that is continuous at only 44 volts. It weighs over 100kg's and, if I up the voltage, it will move a car. Others have used the same motor successfully. On the other hand, there are RC motors that are rated for 20kw that you could hold in your hand. They might power an e-bike if you were lucky. See what I'm saying?
 
#67 ·
Thank you puddleglum for your answers. Yes I had made a big mistake with the HP. Don't normally use them so easy to mess up. I am thinking of using Nimh batteries, D cell 10Ah, about 5000 of them, as the power supply for my motor. I am thinking that Nimh or maybe Lithium Ion are the most power dense batteries that are around. And maybe having 2 50kw motors or a 50kw and a 20 kw.
 
#68 ·
Hello All,

Delighted to find this portal and all the great info. So I'm planning on doing a EV, and have located a motor, and was looking for some advice before I purchase it on Ebay. It is in the $1,500 cost range. Is that a fair price for new unknown motor make/model?

See attached summary.

? is this acceptable for a EV converson? Have not decided on donor car yey, maybe VW cabriolet, small pick up, or Mazda Miata. Would really like to do convertable, maybe a jeep too. Trying to do this on a budget. Hoping for 50 mile range at minimum.

? Does anyone have a clue who makes this motor?

? Any suggestions for controllers.

? What bus voltage should i go with.

? Can i do some type or re-gen or is that too dificult with used/low cost controllers?

? Do i need tach or sensor on motor, i do not see a plug on the pictures.

? Should i go with transmission & cluch or direct to transmission, or straight to drive shaft if i go with non transaxle running gear.

Thanks for the help and advice.

Regards,

Trevor
 

Attachments

#69 ·
Hello All,

Delighted to find this portal and all the great info. So I'm planning on doing a EV, and have located a motor, and was looking for some advice before I purchase it on Ebay. It is in the $1,500 cost range. Is that a fair price for new unknown motor make/model?
Not bad. A new one would probably be twice that. A similar sized used forklift motor might be found for less.
See attached summary.
Interesting.
? is this acceptable for a EV converson?
Probably. It looks pretty nice IMO.
Have not decided on donor car yey, maybe VW cabriolet, small pick up, or Mazda Miata. Would really like to do convertable, maybe a jeep too. Trying to do this on a budget. Hoping for 50 mile range at minimum.

? Does anyone have a clue who makes this motor?
I don't think it was Prestolite like they suggest.
? Any suggestions for controllers.
The usual big boys like Solitron, Zilla, Netgain.
? What bus voltage should i go with.
Using those controllers, any battery voltage up to limit (about 400) and then limit motor voltage to 150 to 200 depending on your need.
? Can i do some type or re-gen or is that too dificult with used/low cost controllers?
Not with a series motor.
? Do i need tach or sensor on motor, i do not see a plug on the pictures.
I suggest a speed sensor. I think all those controller will limit speed for you. And it is a nice parameter to monitor.
? Should i go with transmission & cluch or direct to transmission, or straight to drive shaft if i go with non transaxle running gear.
Up to you.
 
#74 ·
i would like someone to help me.
i came across this motor, and i am wondering could i use it in my ev.

price: 500$
15,2 kW, 236 A, 75 V
1800 rpm na 75 V and 2300 on 96V.

it is rated for 1800 so i dont know if this 2300 is okay to run on.

if i understood correctly, this motor would give me top speed of 60kmh.(around that)

or should i put in another 500$ and take kostov 9"

help me plox :D
 
#77 ·
Nice motor. Looks like robust construction. However it was likely used to drive a pump and therefore has a shaft which will be a bitch for you to use. Also the power rating is for S3 duty cycle of 33%, so the continuous or one hour rating will probably be one third to one half of that figure or 5 to 7kW at 72V. Raising voltage and RPM can increase the rating if good ventilation is provided. Enough for your car? Depends on the car and expected performance (speed, hill climb, payload, etc.).
 
#78 ·
thank you for your reply.
How do you know its S3? (just curious, so i know in the future)
what is downside of raising rated voltage and rpm besides higher temperature and therefore better ventilation needed?
i thought of driving ev in straight terrain (no hills or anything like that), with a top speed around 80-ish kmh, this probably wont do above 50-60 kmh the more i look. correct?
 
#83 · (Edited)
you have to go into the wayback machine to find the datasheet for that one:
http://web.archive.org/web/20090806...-drive/documents/AC90_DMOC645ProductSheet.pdf

but 208v is rms, which is really more like 294v dc pack, the datasheet says 312v min.

so look at the first graph, and slide it to the left by 144/312. So that the knee is at ~623 rpm.

Also the curtis is probably a 500 amp controller, so then pull the whole graph down by 500/600.

so the knee will be at about 416 ft lbs (graph is in nm fyi), which puts you at about 50 hp (37kw) at 623 rpm.

with the dmoc and a 312v pack it says it does 97kw at 1500 rpm. but the thing weighs 189kg!

Plus 3 phase controller costs are not cheap. Even with a kit expect lots of time and several hundreds of dollars.

edit: I'm at a bit of a loss as to how a 312v pack and a 600 amp controller is only making 100kw.
edit2: must be a sqrt(2) * efficiency thing.
 
#85 ·
I hear ya, I keep an eye out for a nice DC motor too, but damn these induction motors are cheap ( I have a 4 pole 7.5hp 1765rpm for $100 on the bench that looks about like an ac51 on paper, with 1.4x longer windings, and of course no testing in that sort of environment or hundreds/thousands/??? of satisfied customers), but then the extra requirements start kicking in. It isn't too bad as hobbies go though, keep ya busy for a while :)
 
#86 ·
Those look like nice motors, but the max speed is a bit low and the rated voltage is a bit high. From what I can tell, these were installed in-line with the driveshaft on the hybrid trucks/vans/busses that they came from, so 5000rpm is probably plenty for that. A rebuild of one of these with a high speed balance and some good bearings would probably make for a very nice motor. I can't tell if they're water cooled or air cooled. It looks like there might be a hose poking out in one of the photos?

A repurposed Prius inverter with either my control board in it, or two of Eldis's boards in it make AC motors more feasible for DIY, though not plug-and-play like the DC stuff.
 
#87 ·
Those look like nice motors, but the max speed is a bit low and the rated voltage is a bit high. From what I can tell, these were installed in-line with the driveshaft on the hybrid trucks/vans/busses that they came from, so 5000rpm is probably plenty for that. A rebuild of one of these with a high speed balance and some good bearings would probably make for a very nice motor. I can't tell if they're water cooled or air cooled. It looks like there might be a hose poking out in one of the photos?
Hi big,

Those were made by Lincoln Electric in Cleveland; a NEMA 286T frame. We used one for a project and balanced the rotor and used precision oil lubed bearings and did well over 10,000 RPM, 12k peaks. With modified windings, 350Vdc bus and liquid cooling, it was capable of over 200kW. Those pictured are TENC (totally enclosed non-cooled). And I think the Azure application was limited to like 400A-phase (for member dcb).

Those are real nice motors--- big but nice. Great extruded aluminum frame shell. A shame they used iron end caps. We had aluminum ends made for ours.

Regards,

major
 
#89 · (Edited)
they have a weird output shaft, not insurmountable though, plus you may need a real drive end bearing. And the seller has zero feedback.

Also most folks are looking at scrap tesla motors, etc, these days, spurred on by a desire for more power if you are going to go through all the effort.

I'm sure there is a niche for these, but 3 phase controller (and battery) costs make it worth investing a little bit more in the motor if it means you will get more out of the rest of your investment.

edit: a pic of the dataplate would help, also folks may want liquid cooled, I'm looking at ODP motors myself. This is TENV, enclosed no fan (can add one maybe), not the best for continuous power.
 
#93 · (Edited)
So here is what I learned about motors from this site. I wanted to post a quick reference so newbs (like myself) do not have to sort through the sticky page.

When looking for a forklift motor:
Get a series wound motor because they have very high torque and handle abuse (over volting) a lot better.
Know the difference between a Spex motor and a Series wound.
When dealing with series wound forklift motors go for higher voltage. (36V may require advanced timing.)
Hp does not directly represent torque (although it does have a factor in its equation).
Get a class H insulation if possible (makes your motor last longer)
Get a motor around 150lbs (Wouldn't risk a motor that's too light, it won't have the oomph you need. a few extra pounds is A-o.k. but a significant amount of extra pounds limits your range)
Get one with a male shaft
A keyed shaft is easier to work with but you can still work with a spline shaft
Try and get the coupler that goes on to your motor when you buy it/rip it out (saves you $$ and time)
When looking for a different motor:
Ac is not the way to go for your first conversion (or do i just have low expectations of myself?)
You can tell if a motor is AC if it is a 1 phase or 3 phase motor
Pancake motors are usually not good candidates for car conversions. (Yeah you saw the one on ebay. They overheat easily)
Golfcart motors are seldom powerful enough for a conversion
Motors specifically made for EV conversions are the best but its gonna cost you.
You do have to look at many factor such as volts, amps (which gets you Hp). Torque is nice to know. Continuous Hp. So many factors!!!
If there is any more helpful hints I'll be happy to add them
Good job! U seems a master of forklifts..
 
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