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Discussion Starter #1
Hey all

I thought I'd chime in and discuss the basics on choosing a forklift motor. In general, I advise people to look for a motor that weighs between 100 to 150 lbs. The heavier the car, the heavier the motor needs to be to push it around. The way I see it is, you don't want Peewee hermin trying to pull you around but you probably don't want to feed Hulk Hogan either, lol.

When searching for cores, look for insulation that is wine colored with yellow banding, brush leads that are still copper color and not scortched, and a commutator that isn't grooved or pitted. Don't be afraid to remove the cover band and have a look inside the motor (and while you're there take a pic to send me). I get a lot of "I wish I had wrote you before I bought this emails" and it's a bummer to read them honestly. I'd bet that almost half the motors I've built are still not up and running yet, so you might not need that motor as fast as you think you might. Sometimes looking to eager to buy not only drives the price up but might also cause you to buy something ill suited for your needs to boot.

Look for armatures that have a commutator with a large bar count as the larger the bar count the higher the voltage it'll take. Also, look for solid field leads (if you're looking for a series motor) or you might end up with a sep-ex or compound wound motor that may not suit your needs. Shafts can be one of the biggest issues in using a lift motor so make sure the shaft is something you think you can attach to or modify. There are motors I reshaft, but there are others that aren't as easy to do, or have no "standard" useable replacement shaft avaiable and then you're looking at needing a custon shaft made which makes them cost prohibitive.

Choosing the right motor isn't rocket science (unless you're a racer, hehe) but does need a little thought thrown at it so the end results are rewarding and meet your needs.

Happy hunting

Jim Husted
Hi-Torque Electric
http://www.hitorqueelectric.com
 

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Aren't fork lift motors usually a slower RPM motor that doesn't lend itself to car use?
I have one but the 3500 rpm range isn't the best.
I would think an Advance type motor would be better suited, right out of the box.
 

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Discussion Starter #3
Actually just the opposite, being they are wound a little courser (heavier wire and less turns) and in general will have a higher RPM at "X" current when compared to the basic "EV" produced motors. As for the stated 3500 RPM's that's determined by voltage and load on the motor and also in general is a decent sweet spot RPM (3K to 4.5K) for a lot of motors.

I've seen and built a number of converted lift motors and they do nicely. It's not EVeryone's cup of tea but for those you are under a budget and are handy with tooling it can be a great way to get a drive motor. Shafts and adapting the motor are the biggest issues when compared to motors that have adaptor plates already designed and available. You usually have to advance the brush timing on these motors (where as the ADC's and Warp's are already advanced) for a higher voltage.

As I posted in another thread any data tag that maybe on the motor is just one point of refference and is usually a 1 hour or continuous duty cycle rating. By adding a blower and forced air cooling, the duty cycle can be increased quite a bit.

If we looked at Killacycles L91 motor for example (motors very close to it in a lift) would only be rated at maybe 48 volts and somewhere around 10 HP, where as Bill's stating around 325HP for the two of his L91's. There are actually a number of lift motors that are very close to, or verbatum to the popular EV motors being used, and with that said are diamonds in the rough just screaming for a new life as an EV drive motor.

Hope this helps
Jim Husted
Hi-Torque Electric
http://www.hitorqueelectric.com
 

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just a quick comment for now. I've located a chinese source of forklift/traction motors called Zibo super motors.

they look to be similar in power ranges but considerably cheaper. 320-460$ but around a 40% retail punishment. still cheap. shipping for a big one for me was quoted at 90$ (haven't bought one yet)
they claim that the Zap zebra truck EVs use their motors.

I asked for the wire thickness to know if they were weaker current wise but they were 25 and 35mm2 for various models which should be enough for quarter mile bursts of 1000A. I have tried to find similar data for other motors but so far no luck. Jim Husted who might well know such data has unwisely decided to be obtuse about it. A decision he will come to regret.

I have some more detailed info on the chinese DC motors, I'll see if I can compile it and post it here later
 

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Discussion Starter #6
Hey Coley

Baldor wouldn't be helpful toward what it'll take to over-volt it as it's not something they do. I'm not sure which Baldor you have so if you'd like to throw me a few pics I'll have a look at it and shoot you some thoughts. In general the larger Baldor's have through bolts that hold the end plates to the housing, and you'll probably need to drill new holes in the comm plate to be able to advance the brushes as the through bolts usually go through channels that are machined in the housing. This is probably going to move the holders far enough over that the field leads won't reach, as they are probably locked into the housing and will need to be extended, so this may not be an easy mod for you to do.

I've never bee a big fan of Baldor motors (way to many reasons to list with the time I have now. I'm not saying you don't have a good EV motor, they just aren't as user friendly or as beefy as most the other motor choices that are out there. Seeing this motor would allow me to have further input.
Cya
Jim Husted
Hi-Torque Electric
 

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here's what I have from Zibo http://www.zev.dk/misc/ZiBoSuperMotors.zip

I might refine it into something more concise at some point. like so many other companies they aren't on top of their information so there are various mistakes. the torque graph for ZC6.3 96V which doesn't exist in the lists of models. two versions with the same name ZC5-72 etc.
in their defense they are much more informative than for instance Advanceddc of USA..

that they don't understand the benefit of concise information on a website once and for all is a mystery to me.. but what can you do..

some guiding plots here of a few of their motors compared to others http://www.zev.dk/misc/torque-curves.gif

and a list of motors: http://www.zev.dk/misc/motorchart.htm the current ratings for the zibos are probably not their max continuous, just some odd rated value that I think they arrive at by giving the motor a fixed voltage and then loading the motors more and more until they find the point where the output is the highest for that fixed voltage. probably a legacy from a time where motors were just fed a fixed voltage.

when I asked about the wire thickness she said noone asks for that. which must mean the engineers of the world don't think their systems through. unless I'm wrong in thinking the wire thickness is a vital parameter for the motor's performance
 

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Quote:
"Seeing this motor would allow me to have further input"

I can email you a picture of it.

The spec plate says:

Spec 29-1584-2137
Frame 2152 75440
HP 8
Volts 72
Amp 98
RPM 3200
Serial #281

It weighs about 160 lbs
The most Amps that it pulls on my gauges (climbing a hill) is 170.
It never gets much more than lukewarm after a 10 mile run.
Pulls my Yugo 40 mph on good flat road in 3rd gear. 41 in 4th.
 

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you use a 72v controller?
if you want to go faster just feed it a bit more voltage.
you can think of voltage as that paying for the energy that the torque and rpm demands. if the voltage isn't there to pay then it stops going up in rpm
that's why you can have strong acceleration at low speeds but it loses the will to go at higher speeds.
that how I make sense of it at least and I think it's accurate in this context
 

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Discussion Starter #10
Hey Coley

feel free to send pics anytime and I'll put an eyeball on them. If there is a cover band (and you want to remove it) it'll help me to see the comm and brush leads and such for a better idea as to it's over all health. FWIW, it's hard to say if that's a 1 hour duty cycle or a cont duty cycle on the data tag.
Cya
Jim Husted
Hi-Torque Electric
 

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I had the motor clear apart when I got it, to check out all wear. There are 2 brushes at each of 4 locations.

The one thing that concerned me, was that with rotation I need, the brushes are not being pushed against the heavy brass holders.

Instead they are being held in place by the springs. So far in over 900 or so miles, it hasn't been a problem.

I won't have it back on the hoist for more pictures for a while, as the shop has gotten busy again.

I use my hoist as a work bench....adjustable height and all...

I added a photo of my Baldor motor in:

http://www.evalbum.com/ Look up Illinois, Yugo
 

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if your batteries are 80Ah (you should write that on the EV album) and say you get about 55% of that in EV use because of Peukert, that's about 210Wh/mile (from the batteries) if you managed to go 15miles on a charge without it limping. if you want to add that to evalbum.
 

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Since I'm just getting into this I thought I'd ask a question regarding forklift motors.
I just looked at a fork lift. It's rated for 2500lbs and has a 36 volt battery. The nameplate shows 4250 w/o batts and 7200 or so with so about 300lbs of batts. My thought was to buy it and scrap out everything except the motor. Scrap batteries I've been selling have been netting $.20/lb so I could get my money back on the batts and steel/iron and have the motor for free. I couldn't see the motor very well but it looked like there were actually 2, I'm assuming that one for is drive and one for the hydraulics that work the mast. Does this seems right? Also, the donor car would be a 97 Corolla that I just happen to have setting around with no motor or trans. Could the fork lift motor be adequate to motivate a 2300lb curb weight vehicle?
thanks,
Mel
 

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Discussion Starter #14
Hey Mel

A 2500 lb capacity lift will have a decent sized drive motor if it's a sitdown type truck. If it's a stand up type it'll have a smaller motor (probably a 7" diameter 80 lbs). There are people using these 7" motors in lighter conversions but they are usually blower cooled. There are so many types and styles that I'd really need a picture or as good a decription as you could write to have better input.

I did notice you stated that you have no tranny, which is probably something you're going to need. Going direct drive requires a pretty good sized motor to handle the grunting it's got to do on take off.

As an FYI lifts can have from two to four motors on them as there are twin drive, twin pump, steering pump, ect. Besides pics, knowing what make is it(Hyster, Yale, Clark, ect) would help me I.D. it. If / when you get to the motor removal stage, pics of the brushes and comm, shaft, will allow me to see the basic condition of the motor (best pics can show anyway, lol) I've analized pics from all over the world for people and can tell alot from a pic (or a dozen, hehe)(yeah sometimes I make people take more 8^) (kind of a dark side of the moon thing)
Hope this helps, need more info (take more pics, LMAO)
Cya
Jim Husted
Hi-Torque Electric
 

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Hey mjones,

Buying a forklift, and then selling it for scrap to get the motor for free can work.

That's pretty much what the Forkenswift guy did.

Read his whole posting on Ecomodder. I think it took me three nights to read altogether.

I have my eye on a Nissan forklift motor, but I need to get take it out of the lift to get a better look at it, and the seller is out of town for a few weeks still.
 

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I actually do have a trans but it's an auto w/od and requires electronics to operate properly. From what I've read autos aren't the best for conversions.
I've located someone to haul it so I hope to be disassembling it this weekend. It is a Baker FTA-030.
 

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I got another lead on a forklift motor.

This time, it comes with an entire forklift.

I got a call from a guy replying to a Craigslist ad I posted a while ago.

He is a maintenance guy for the local Veterans Administration.

They are getting rid of a Raymond brand 36V stand-on electric forklift.
He says it is in running condition, but does not have batteries.

I am planning on going to look at it on Friday. Maybe I can bring 3 12 volts with me.

I think I can get the whole thing for around $500.

Maybe I could turn the forks into a car lift for my garage!?
 

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Discussion Starter #18
Hey Ben

Just a quick heads up to never throw more than 12 volts to the motor without the load. I figuer you're talking about Jimmyrigging the lift to test it but wanted to make your you didn't pull the motor and then it with 36 volts as that'd probably put the RPM's at or beyound the limits. The standup will probably have a 7" 80 lbs motor as the drive and with some mods and blower cooling can drive a small conversion. If there is anyway to grab pics (or a motor number) I might be able to shed some light as to what type of shaft it has and to make sure it has a drive end bearing (some plug right into a gearbox and don't have a drive end bearing. It can be overcome but adds to the list of things you'll want / need to do to the motor.
Hope this helps
Cya
Jim Husted
Hi-Torque Electric
 

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So if you buy a 36 volt forklift motor, how can you know the max voltage it will handle? Will any 8 inch 36/48 volt motor work ok with 144 volts? How does the HP change with added voltage?

Thanks for all the info
 

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it's my impression that you can in principle feed them any voltage. it's not like a 24V motor will melt if you feed it 36V. volt in principle can't hurt it BUT volt motivates current to appear. the higher voltage the more current will tend to appear and current can destroy a motor. to really understand it you have to understand the physics concept of work. nature has a magical way of ensuring you pay for the work a motor does. work is the force (or torque) applied over a distance. if you apply force and nothing moves you don't have to pay for it. just like a paper weight is free force. that force (or torque in the case of a motor which is just force going in circles) comes from the current and the work done during rotation is paid for with voltage. you can imagine a worker that only does as you pay him.
this means for instance if the motor is stalled, let's say up against a wall and can't turn even a little voltage will make the current rise a lot because there is no rotation and no work done. you pay voltage and it tries to make work. when it can't the current rises dramatically, in theory infinitely if it weren't for resistance in the wires. but going 100km/h it wants a lot of voltage to maintain a current level. if you don't feed it the current will drop to the level you feed it. nature has a 'magical' way to make sure you get exactly what you pay for.
so voltage motivates current in a balance with how much work the motor does. slow rpm it's easy to motivate current to appear. high rpm it takes more voltage.
a motor's limit is a current limit and not a voltage limit BUT there is an indirect voltage limit because the motor can only handle so high an rpm for mechanical reasons.
let's say a motor is rated at 150A continuous and 5000rpm and that at that speed it takes say 100V to keep the current level at 150A. so you might say that 100V is the max for that motor BUT a motor can take more current briefly so let's say you want it to peak up to 450A then you need 300V to keep that level at 5000rpm. that would be 450Ax300V=135kW (or around 150HP after efficiency)
the power formula you can use is

P = T x w = T x Hz x 2 x Pi where T is torque, w is rotational speed in radians per second, Hz is revolutions per second, Pi is 3.1415...

torque is a direct result of current in the motor and that relationship you can look up in a spec sheet for the motor. a current torque graph (not always available) here are some example curves: http://www.zev.dk/misc/torque-curves.gif

once you have that for your motor you can use the above formula to roughly figure out how much voltage your desired performance will take at the motor's max rpm. it gives you a power value for your chosen current which you can then get voltage from using

P = I x V

where I is current and V is voltage. P is power.

IIRC :)
 
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