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Old 07-26-2012, 05:12 PM
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Default Water cooling methods and effectiveness.

I feel water cooling deserves it's own thread. It is a topic almost everyone has wondered about at one time or another.

I want to start it all out with an accomplished result...Almost everyone has seen my motor.

My theory was to perform motor cooling by induction with the water cooled tubes.
It used Propylene-glycol/water 50%-50% mix. The pump was about 2 gallons/minute. It used a large aluminum heat exchanger and lots of air.

Busted: Today I drove half way home with no water circulation, maintaining 60 Deg. C. (9 miles and 105-F. AMB.), I stopped, plugged in the pump and drove home. It was sitting on 55 Deg. C......

5 Degrees measured at the stator windings........

My Thoughts: 5 degrees is disappointing. I believe it was because of lack of contact surface. It was not worth doing.

Conclusion: Unless your motor is operating within the last 30% region, this cooling method is not effective. The only way it would be effective is if you were really marginal and it kept the motor from over temping.

I am in the first 30% region. I really do not need any type of extra cooling.
It just adds extra cost, weight, complexity and ultimately draws from the pack (mileage).

Miz
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Old 07-26-2012, 05:19 PM
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Default Re: Water cooling methods and effectiveness.

Does yours have any internal fan? What gear were you driving in? With my air blower I found it barely made any difference if I drove in 2nd, but was much more significant in 3rd and 4th as the delta between motor and ambient increased.
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  #3  
Old 07-26-2012, 07:39 PM
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Default Re: Water cooling methods and effectiveness.

AC50's have a built-in fan on the drive end that pulls air through the motor and exhausts radially out the end cap through 4 slots.

I also have a ducted fan inside the intake tube. It was mostly to compensate for the air filter element restriction.

I was in low gear, about 5,100 RPM, 1.72:1 with a 6.14:1 axle ratio and a 32" tall tire. I was cruising at 100-110 amps @45 MPH.


I hope this helps.

Miz
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Old 07-26-2012, 08:25 PM
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Default Re: Water cooling methods and effectiveness.

I've used chiller plates (in non EV applications) that have the copper tubing pressed tightly into channels on an aluminum plate. The plate is mounted with a thermal conductive paste, all in an effort to improve thermal contact with the part to be cooled.

It was worth a try. Thanks for posting the results.

Last edited by Joey; 08-02-2012 at 12:19 PM.
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Old 07-26-2012, 08:41 PM
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Default Re: Water cooling methods and effectiveness.

Quote:
Originally Posted by mizlplix View Post
I feel water cooling deserves it's own thread. It is a topic almost everyone has wondered about at one time or another.

I want to start it all out with an accomplished result...Almost everyone has seen my motor.

My theory was to perform motor cooling by induction with the water cooled tubes.
It used Propylene-glycol/water 50%-50% mix. The pump was about 2 gallons/minute. It used a large aluminum heat exchanger and lots of air.

Busted: Today I drove half way home with no water circulation, maintaining 60 Deg. C. (9 miles and 105-F. AMB.), I stopped, plugged in the pump and drove home. It was sitting on 55 Deg. C......

5 Degrees measured at the stator windings........

My Thoughts: 5 degrees is disappointing. I believe it was because of lack of contact surface. It was not worth doing.

Conclusion: Unless your motor is operating within the last 30% region, this cooling method is not effective. The only way it would be effective is if you were really marginal and it kept the motor from over temping.

I am in the first 30% region. I really do not need any type of extra cooling.
It just adds extra cost, weight, complexity and ultimately draws from the pack (mileage).

Miz
I did the same thing to one of my motors and now I am doing air cooling on my dc motor.
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Old 07-26-2012, 10:14 PM
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Default Re: Water cooling methods and effectiveness.

Quote:
Originally Posted by mizlplix View Post
Busted: Today I drove half way home with no water circulation, maintaining 60 Deg. C. (9 miles and 105-F. AMB.), I stopped, plugged in the pump and drove home. It was sitting on 55 Deg. C......

5 Degrees measured at the stator windings........

My Thoughts: 5 degrees is disappointing. I believe it was because of lack of contact surface. It was not worth doing.
Hi Miz,

I wouldn't throw it out yet. It might show only 5 but that is with a fairly cool motor. 60C on the stator winding is hardly taxing the motor. Get it up to 150C and try your experiment.

The amount of heat removed and resulting reduction in winding temperature is dependent on the temperature differential. So there was little difference between the coolant and ambient and little difference between the coolant and the motor frame. So you saw a small difference w & w/o coolant circulation.

Jacket liquid cooling works best on totally enclosed motors running continuously. Every little bit helps when you're pressing the machine to the limits. Limit on your motor is 180C, but use around 150 on the measurement.

I think you need to run that rod harder

major
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Old 07-26-2012, 10:19 PM
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Default Re: Water cooling methods and effectiveness.

Quote:
Originally Posted by major View Post
Hi Miz,

I wouldn't throw it out yet. It might show only 5 but that is with a fairly cool motor. 60C on the stator winding is hardly taxing the motor. Get it up to 150C and try your experiment.

The amount of heat removed and resulting reduction in winding temperature is dependent on the temperature differential. So there was little difference between the coolant and ambient and little difference between the coolant and the motor frame. So you saw a small difference w & w/o coolant circulation.

Jacket liquid cooling works best on totally enclosed motors running continuously. Every little bit helps when you're pressing the machine to the limits. Limit on your motor is 180C, but use around 150 on the measurement.

I think you need to run that rod harder

major
OK I will work it hard.
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Old 07-27-2012, 12:04 AM
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Default Re: Water cooling methods and effectiveness.

Thermal compound (paste) might help some. I doubt the motor surface or the tubing surface is perfectly smooth, the compound could help fill the gaps

I was thinking the same thing as major, heat flow is proportional to temperature difference. It should move much more heat at higher temperatures.


I had been thinking of trying the same thing for a while now, I'm glad you posted this.
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Old 07-27-2012, 12:06 AM
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Default Re: Water cooling methods and effectiveness.

Quote:
Originally Posted by subcooledheatpump View Post
Thermal compound (paste) might help some. I doubt the motor surface or the tubing surface is perfectly smooth, the compound could help fill the gaps

I was thinking the same thing as major, heat flow is proportional to temperature difference. It should move much more heat at higher temperatures.


I had been thinking of trying the same thing for a while now, I'm glad you posted this.
Using air cooling with water cooling will help keep the motor cooler.
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Old 07-27-2012, 03:33 AM
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Default Re: Water cooling methods and effectiveness.

you would probably do better for heat transfer to have a jacket with baffles in it.
bond the jacket to the outside of the motor with silicon thermal compound like is used for IGBT's
The Seimens 96KW 3phase uses internal liquid cooling.
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Last edited by bjfreeman; 07-27-2012 at 03:36 AM.
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