Liquid cooling an industrial AC motor

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BigMouse
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Liquid cooling an industrial AC motor

Post by BigMouse » Sun, 21 Jul 2013, 05:46

I'd like to use this thread to discuss options for liquid-cooling an industrial ACIM. So far, I've heard of three possible options, which I'll briefly discuss below:

1. Install a water jacket.

This would involve installing a water jacket on the outside of the motor frame. When considering this option, I've thought of putting the entire frame in a lathe and turning the fins down enough enough make them round and concentric with the inner cylinder. Then simply wrapping the motor in a piece of sheet metal with a water manifold on either side. Challenges with this method would be sealing, dealing with the junction box, and motor mounting.

2. Make a custom housing

This is like what Readykilowatt did with his ute here: Readykilowatt Holden Ute

Challenges would be cost, sourcing of stators, and mounting. This option is great for someone wanting to make a business selling motors, but not really something to be done in a garage.

3. Internal oil cooling

This would be basically the same as it done in the Toyota Prius transaxle and other hybrids. The windings are cooled directly with oil splashed on to them by the spinning rotor. Oil could be cooled either by pumping through the motor (which would introduce a problem of maintaining the proper oil level) or via a heat exchanger inside the motor.

Challenges would be sealing of the motor case (especially the junction box), distribution of oil inside the motor, heat exchanger design and fitting, and oil level control in the case of an external oil circuit.

The Prius uses standard ATF fluid and there doesn't seem to be any issues with conductivity. The motor winding terminals are uninsulated and exposed to the oil. The Prius also uses a magnetic sump plug to capture any ferrous metallic particles in the oil.

I'd like to hear any thoughts from the forum on this topic. Please share any examples that you've come across for custom liquid cooling methods of air-cooled EV motors.
Last edited by BigMouse on Sat, 20 Jul 2013, 20:25, edited 1 time in total.

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Liquid cooling an industrial AC motor

Post by jonescg » Sun, 21 Jul 2013, 06:09

I wonder if doing a fully custom motor build would be easier. May not be cheaper, but that's not why we do this kind of thing Image. I'd be interested to know if you could make a short fat motor for more DD torque. You'd be going radial flux out of simplicity, but axial flux is the bomb for power to weight. Said motor would definitely need liquid cooling, but you could machine your case and jacket easy enough, since you will need to house the laminations in something.

Oil cooling looks like trouble though, and would make your vehicle look a bit... you know...ICEy.
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Liquid cooling an industrial AC motor

Post by BigMouse » Sun, 21 Jul 2013, 06:23

jonescg wrote: I wonder if doing a fully custom motor build would be easier. May not be cheaper, but that's not why we do this kind of thing Image. I'd be interested to know if you could make a short fat motor for more DD torque. You'd be going radial flux out of simplicity, but axial flux is the bomb for power to weight. Said motor would definitely need liquid cooling, but you could machine your case and jacket easy enough, since you will need to house the laminations in something.

Oil cooling looks like trouble though, and would make your vehicle look a bit... you know...ICEy.
There's a very involved thread somewhere out there on custom motor building, including stamping laminations and all that good stuff. I forget which forum it's on, but there were quite a few pages of people trying to develop and open-source hub motor. That's way beyond the scope of what I'd like to do here though.

Personally, I like the idea of oil cooling the windings. Even if it does involve oil. There's still oil in the gearbox, differential, power steering, and air conditioning anyway. There's no getting away from that*. It lasts forever and at least we're not burning it!

Most industrial AC motors are already totally enclosed anyway, with sealed bearings. Shouldn't be too tough to stick an o-ring in each end bell, or even some silicone sealant. I'm more concerned with whether the oil can make it from one end of the motor to the other. The Prius proves that oil cooling can be done. The size of the water/oil heat exchanger on the Prius transaxle for cooling MG2 is tiny too.

I'm looking for ideas on how liquid cooling can be implemented on an off-the-shelf or junkyard motor.

*Before you say it: direct drive, electric (or no) power steering, and who needs aircon anyway? ;-)
Last edited by BigMouse on Sat, 20 Jul 2013, 20:27, edited 1 time in total.

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Liquid cooling an industrial AC motor

Post by Simon » Sun, 21 Jul 2013, 08:54

What about a total loss water cooled system? Extend the cooling fins and run a water mist over the motor case.


Here is a paper on the Prius motor thermal management. http://www.ornl.gov/~webworks/cppr/y2001/rpt/122586.pdf

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Liquid cooling an industrial AC motor

Post by BigMouse » Sun, 21 Jul 2013, 16:31

Simon wrote: What about a total loss water cooled system? Extend the cooling fins and run a water mist over the motor case.


Here is a paper on the Prius motor thermal management. http://www.ornl.gov/~webworks/cppr/y2001/rpt/122586.pdf
Interesting idea. It would be difficult to 'extend' the cooling fins. How would that be accomplished? Constantly refilling the cooling water wouldn't be very user friendly either.

Those ORNL papers are a gold mine of information on hybrid motors. Image

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Liquid cooling an industrial AC motor

Post by woody » Wed, 24 Jul 2013, 13:17

I had a thought to run copper (ali for no galvanic action) pipes jammed between the fins and run water through them.
Another was to put the motor in tight (Ali?) duct and fan cool it by blowing air through.
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Liquid cooling an industrial AC motor

Post by Tritium_James » Wed, 24 Jul 2013, 20:35

Woody,

Hammering aluminium tubes in between the fins works from a mechanical point of view (no cracks or leaks) - I tried it on a motor we have here. What I don't know is to what extent it helps cool the motor! I only tried a couple of tubes we had floating around, and didn't do the whole motor. But the idea is certainly worth pursuing.

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Liquid cooling an industrial AC motor

Post by Richo » Wed, 24 Jul 2013, 20:54

At what point do you need water cooling?

Perhaps just an air scoop would be the way to go.
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Liquid cooling an industrial AC motor

Post by a4x4kiwi » Wed, 24 Jul 2013, 21:47

Hi all,

See my experiance here http://malfunction.faed.name/search?q=fan

When you most need the cooling is when the vehicle is stationary!

Use a thermostaticly controlled fan or water cooling that runs AFTER the vehicle has stopped.

It wouldnt turn on in the winter but in the summer it would run for quite some minutes after getting home.

My system was 48KW max. in a 15kW motor.

If I were using an induction motor again I would glue with some thermaly conductive compund tubes between every fin (100% water cool) or every other fin. 1/2 water 1/2 air cooled.

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Liquid cooling an industrial AC motor

Post by Troglodyte » Sat, 15 Feb 2014, 21:24

I recall reading about an ICE conversion using a used Prius motor. Presumably it retained the standard Prius cooling arrangement that reportedly uses transmission oil. Anyone know what is the availability & cost of Prius motors, and whats involved in connecting up the oil cooler ?? Whilst I haven't had a close squiz at a Prius motor, a transmission cooler & pump / fan doesn't sound like an impossible undertaking.

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