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Starting a Truck conversion with a Forklift motor and I have some motor questions

5K views 24 replies 7 participants last post by  theonetruerat 
#1 ·
So, I haven't posted In a while because my electric boat project stalled and I have been working like a mule but .. . .

The motor recently blew on my farm truck and since I already had a drive motor taking up space I've decided to do a conversion. I'll post the build in a different forum.

This is the motor I'm using, It's a bit on the big side but I already have it and it's light compared to the cast iron engine I pulled out - and It will fit.the space just fine.

This motor has a cooling fan which has it's own drive. I'm wondering if anyone is familiar with this and could give me any pointers on how it's powered. It has a three prong plug and I'm unclear how it should be hooked up. Not sure if one is neutral and the other two are low/high I'm planning on spinning the fan and poking the plug with a volt meter to see what that shows but I'd love a little guidance.

also there is what appears to be a signal wire on the other end of the motor if anyone has a clue what that is for.
 

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#2 ·
Some fans have a 3 wire interface: ground, power positive and tachometer signal. You can probably isolate the tach wire by trying to spin the fan with compressed air and measuring frequency on the pair of wires. Although if the tachometer sensor is an active kind like Hall, the fan may need to be powered too :(

The other connector is likely going to some thermistors for temperature monitoring. You should be able to isolate those by checking the resistance, which should go into several kohms. It is also possible that there is another tach for the motor itself.
 
#3 ·
Is it a Series or a Sepex motor? case length and diameter? Weight? Some interior shots of the windings, commutator, and brushes would be helpful to evaluate the motor.

Also, pictures, type(s), and dimensions of the output shaft(s) would be good info to have.

What is the vehicle you want to put this in?
 
#5 ·
Since the 11 kW rating is at 48 volts I assume that the plan would be to run it at higher voltage, like all the rest of the "forklift" (or other industrial brushed series DC) motor conversions. It still won't handle the sustained power that the original engine could provide, of course. Average power use of even just 11 kW might be adequate for the truck at moderate speed.
 
#6 ·
Again, it doesn't matter what voltage you run at, the magic smoke starts coming out after 15 sec at 11kW according to the nameplate.

11kW is your 0-30mph sprint with it floored. Getting a TRUCK to 50 on 11kW is a stretch, don't you think? And you can only run it there (say you start off on a hill) for 15sec.

I would not push that motor's output without a thermocouple monitoring winding temperature. I'd also add a cooling jacket to it.
 
#7 ·
Again, it doesn't matter what voltage you run at, the magic smoke starts coming out after 15 sec at 11kW according to the nameplate.
It's not that simple. The rating is probably based on heating due to current; the same current at higher speed (which requires higher voltage) may result in acceptable heating.

11kW is your 0-30mph sprint with it floored. Getting a TRUCK to 50 on 11kW is a stretch, don't you think? And you can only run it there (say you start off on a hill) for 15sec.
No, with higher voltage the power for that sprint will be higher... as it certainly needs to be for performance that most of us would consider acceptable.

I have no idea what the truck is (maybe it's a little old Ranger), but yes, 50 MPH on 11 kW seems unlikely.

The 11 kW rating on the placard (at 48 V, and a fixed and unknown speed) is for 15 minutes, not 15 seconds.

I would not push that motor's output without a thermocouple monitoring winding temperature.
I agree. The same could be said for any of the "forklift" projects.
 
#9 · (Edited)
Power is the same no matter the combination of voltage and current, but the limitation of the motor isn't power at all - it's the heat generated internally and the ability of the motor to dissipate it. And that certainly does depend on current and on rotational speed.

But if the point is to convince theonetruerat that an antiquated motor intended for 48 V operation is not suitable for a modern vehicle, I'll agree with that. ;) On the same basis, the entire NetGain product line - other than the HyPer 9 (which they don't manufacture) is also unsuitable. None can sustain significantly more power than the random motor discussed in this thread.
 
#10 ·
Sorry, I guess I stuck a picture of the wrong motor badge - it's 9 KW at 1 hour. It's going in a mid 80s Toyota that is super light (most of the truck is gone) the truck hasn't gone over 25 MPH for years - hasn't been out of low range for years. It, won't be going more than 10 miles at a stretch either.

The motor is about 11" diameter and about 16" long.


I'm mostly interested in sussing out the cooling fan. I was hoping someone had dealt with a similar motor before and could give me the skinny. I'll put a volt meter on it when I get back to my shop and spin it with an air gun. See what that tells me.

thanks to everyone who took the time so far.
 
#12 ·
So, I haven't posted In a while because my electric boat project stalled and I have been working like a mule but .. . .

The motor recently blew on my farm truck and since I already had a drive motor taking up space I've decided to do a conversion. I'll post the build in a different forum.

This is the motor I'm using, It's a bit on the big side but I already have it and it's light compared to the cast iron engine I pulled out - and It will fit.the space just fine.

This motor has a cooling fan which has it's own drive. I'm wondering if anyone is familiar with this and could give me any pointers on how it's powered. It has a three prong plug and I'm unclear how it should be hooked up. Not sure if one is neutral and the other two are low/high I'm planning on spinning the fan and poking the plug with a volt meter to see what that shows but I'd love a little guidance.

also there is what appears to be a signal wire on the other end of the motor if anyone has a clue what that is for.
Excellent - That is a Hitachi motor - its rated to run continuously at 10 Kw - 48 volts and 200 amps

I'm feeding a very similar motor with 1200 amps and 340 volts - but in a much lighter vehicle

200 amps will be perfectly safe - and at 1400 rpm will give you your 10 kW

At 2800 rpm it will give you 20 kW -

and at that higher rpm you will get more cooling so you can go to 400 amps - which gives you 40 Kw

at about 4000 rpm and 500 amps you will get about 75 kW - comfortably and safely

You need to feed that motor with a 150 volts and 500 amps - 75 kW - 100 Hp

HOWEVER that is with a motor like mine that has a cooling fan on the motor shaft!!!!

That motor has some sort of fan at the drive end - it can be an electric fan - or it may be some sort of geared fan to get more cooling at low speeds
 
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