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Industrial AC induction motor

833 Views 11 Replies 7 Participants Last post by  remy_martian
Hi, I have 2, 3 phase AC motors that were removed from a factory. I'm not sure what they're ratings are as there is no information on them. But it takes two guys to be able to lift them.
I'm thinking of using one, or maybe 2 for a conversion.

My question is, could I just use a VFD to control the speed of the motor? Obviously the VFD would either have to accept the DC voltage, or maybe I could convert DC to AC first and then use a standard AC VFD?

Or could I even use an inverter from an EV to control it?

Thanks.
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If 2 guys can lift a 60Hz industrial motor, I doubt they have enough HP to drive a car.

What are the nameplate ratings?
I think you're going to be faced with a few issues. Industrial VFDs just output a frequency, whereas an EV uses the accelerator pedal position to command a certain torque (as opposed to speed). They also use permanent magnet synchronous motors with rotor position feedback, not induction motors that have slip.

I'm not sure about all VFDs, but I know some of them rectify the input to DC, so maybe in theory you could connect the battery there? It would take a lot of doing, though, and you still have to figure out how to use the accelerator pedal to command a torque instead of a speed. Generally, induction motors are not considered suitable for ev conversions.

Using an ev inverter on an induction motor would probably be problematic, not least because of the lack of position feedback. You'd also need a custom control board such as an openinverter to have any hope of configuring it properly (if it's even possible).
Most industrial motors are induction, afaik...a VFD would work, but I doubt it would be affordable for the HP needed by a vehicle as compared to the "standard" approaches we use on this forum. That includes motor costs, with the industrial 3 phase being "free".

It's all moot if the HP I suspect is not there.
Ah well probably best to forget about that on then, nevermind.
Not sure what I can do with the motors. Don't have enough money to do a proper conversion from a EV donor.
I guess I'll just carry on getting into debt having to pay for Petrol. Doesn't help that I have a 2.5l engine!
You might consider a motorbike conversion if they're 5hp or better. Still a lot of weight, though.
Industrial VFDs just output a frequency, whereas an EV uses the accelerator pedal position to command a certain torque (as opposed to speed).
Not quite - a VFD can have any control method, but it is true that industrial drives most commonly accept a speed request as an input, rather than a power or torque request.

They also use permanent magnet synchronous motors with rotor position feedback, not induction motors that have slip.
As already noted, most industrial motors are induction type, and VFDs are routinely used to control them.

I'm not sure about all VFDs, but I know some of them rectify the input to DC, so maybe in theory you could connect the battery there?
Yes, in general all VFDs rectify the input power to DC, and it may be feasible to provide DC power from the battery to the DC stage of the VFD, using on the inverter section and removing (or just disregarding) the input rectifier.

Generally, induction motors are not considered suitable for ev conversions.
Perhaps you mean industrial induction motors? The entire HPEVS motor line is induction, the Siemens motors used by Azure Dynamics and many conversions since are induction, and of course all Tesla motors before the Model 3 are induction.

If you mean that industrial motors are unsuitable, then I agree that typically they are not wound for operation at a voltage which is desirable in a DIY conversion, and they're heavy. The HPEVS motors are an industrial line, but wound to their specifications and in more suitable housings for automotive use than a typical industrial application would use.

Using an ev inverter on an induction motor would probably be problematic, not least because of the lack of position feedback.
There are "sensorless" controllers, and a sensor can be added to a motor. By the way, induction motor control uses speed sensing, not position sensing (although of course the rate of change of position is speed).
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Why do so many responders to any interesting questions her just ridicule or disparage ideas?
I had expected that this forum supports people to try stuff - even if it fails - to add to general learning.
Any vector control VFD can control and command torque, rather than just frequency.
Every VFD can take DC input and bypass the rectifier stage.
Any industrial motor can drive a vehicle.
The question is only how fast, how steep a hill and for how long.
Some industrial motors are built into aluminium cases and can be light enough to be suitable, al though any above 20kW are less likely to. 20kW and up VFDs are very expensive. So the attempt would need a low cost source. Lots of hurdles, yes, but no reason not to examine the solutions.
To the OP: ignore the neigh sayers and keep on reading and learning about electrical engineering!
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First thing OP was asked was the nameplate rating.

It's assumed to be an iron motor case otherwise -- a pull of an industrial motor in the UK that's of age not to be reused by the company that pulled it is extremely unlikely to have an aluminum case...it's obsolete and next to worthless.

Also, show me where I can buy a cheap 20kW VFD and I'll put it on my VMC. The last USED one I bought was 7.5kW and was a $grand USD. You colonials pay VAT etc etc on those numbers.

So a free 150lb motor is no longer free once you add the VFD. OP was smart enough to do the math -- I suspect may be an industrial electrician.

A used VFD becomes more expensive than a Leaf Drive Unit, which comes with the gear reducer for the same money and is not in a environmentally-induced-failure prone housing and does have the temperature range of operation of a roadgoing vehicle that an industrial VFD does not.
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Ah well probably best to forget about that on then, nevermind.
Generally, the motors aren't the expensive part of doing a conversion. You do have the option of getting nearly free and more suitable motors, if that's your restriction. Batteries is the corner you probably can't cut.

Industrial induction motors are probably more trouble than they're worth.

I guess I'll just carry on getting into debt having to pay for Petrol. Doesn't help that I have a 2.5l engine!
Honestly, very few people will ever recover the costs of doing a conversion, in the gasoline saved. You make an EV because you want to, not because it's cheap to.

You can buy a used Leaf for like, $5k. Less if it needs work. That's your cheapest route into an EV.
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I agree with Matt, EVs are a good way to spend money and never get it back, I have built hundreds of them, made a ton of money doing it, But I dont own one, and dont want one. If you take a gal of gas , it weighs about 8.5 lbs.
In my 83 S-10 I can go aprox 25 miles, If I take 8.5 lbs of batteries, I can go about 2 miles at best . EVs are for people that want them for what ever reason. Factory built EVs will always fail. just like all the ones they make today, there all on a recall now, reason ???? Factory built ones use the cheapest parts, the cheapest of everything and I think, NO BMS. or one that is shit poor . Some one building there own , in most cases will use quality components , batteries, controllers , everything, and A good BMS . and use it for the way it was intended for them, and NO one else .
Just my 2 cents....
If I take a 3500 lb gasoline car, I can get 30mpg.
Your 3500lb long bed S10 might get 24mpg (I had an 85).

If I take my 3500 lb EV, I can get 120MPGe

My math says I am 5x better on efficiency cost with my EV and f*ck your stinky, explosive, gasoline container.

My 3 year old OEM EV has high quality components that are reliable - it's never failed. It has the same range as it did new, 30,000 miles later. I seriously doubt any of your conversions are comparable to a recent factory EV, and your S10 definitely is not if it's anything like mine was. The block on my 84 Fiero cracked outside warranty at 18k.

When I get up in the morning, I can go 260 miles while wasting not even a second of my busy day at a filling station. That is verry nice. When I run the truck, first stop is a fillup, because I can't bring myself to drop $90 to fill it at the end of a hauling run.

The best thing of owning an EV? The only time I give a f*ck about gas prices is the once a month or every couple of months I need to run the 9.5mpg GMC towing the trailer. I can run into town and back for a teryaki and it costs me a buck...with the truck, it'd be a $20 adder to that teriyaki. I don't think twice about going anywhere....I just go.

Bonus - I get 4,000 miles a year of FREE driving from my utility...just for letting them ask me if they can load shed my smart EVSE.

Gas and diesel light vehicles are worthless trash now. Obsolete.

The really sad thing is that oil industry workers and states feel threatened by EV when the setback is minimal, almost zero:

"Exxon is a big outlier here and is predicting a much earlier end to gas vehicles than most other groups.

However, Woods still claimed this isn’t a threat to Exxon’s business. He said that even if all new cars were electric by 2040, that would only drop oil demand back down to 2013-2014 levels by Exxon’s calculations. Since the company was profitable then, he sees a future where it can remain profitable, even with that level of demand
."

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