Motor cooling as function of speed

[ZeroSeq]

Hello all,

I have been scouring the internet including as many threads as I could find in relation to motor cooling as a function of speed/frequency. I cannot find it in any motor protection standard or white paper across multiple manufacturers (including IEEE stds, GE industrial practice handbooks, induction motor textbooks, etc.). Does anyone have any idea where I may find a table of values or cooling curves for TEFC motors up to 5000HP (ie. heat dissipated as function of motor fan speed).

The reason I need this is I am trying to apply minimum load value (A) at zero speed for a motor relay setting.


Any help would be appreciated.

Thanks.

 

[itsmoked]

There are so many variables associated with what you ask that I cannot believe the curves you're looking for exist.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[mikekilroy]

The reason I need this is I am trying to apply minimum load value (A) at zero speed for a motor relay setting.

for a single motor. Sounds like you do not need to research all motors?

This would be a very easy answer if you just ask this particular motor's manufacturer; I am sure they can tell you very quickly what maximum load THAT motor can have at 0 speed.

Typically for a TEFC asynchronous motor it is always 0 load without additional cooling. Not just 0 load, but you cannot even leave it powered on as the I^2*R losses just from the magnetizing current alone will overheat it.

http://www.KilroyWasHere<dot>com

 

[Parchie]

Out of the box, methinks you just have to consider a separate cooling motor blower to blowoff heat from your motor. It's simpler, imho.

 

[petronila]

Hello ZeroSeq

Just take account the rules for fans, when you operate the motor a speeds below rated speed the fan will move less volume of air, this is why manny motors are driven with VFDs are cooled with forced air.(external ventilation at constant speed).

For this matters is better taht you can consult EASA, they have a great group of experts that can provide you solutions also you can take a look of the book Fan Handbook of Frank P. Bleier.

Regards

Carlos

 

[ZeroSeq]

Thanks for the responses, I kind of figured I would not be able to find such information.

Mike, you are correct it is for a specific motor and I will have to go back to the manufacturer for more information. I was basically looking for an easy fix so I didn't have to do that, which is like pulling teeth.