# Armature temp



## PZigouras (Jun 5, 2010)

Does anyone know what the recommended arm temp is on the comm side of the ADC 8-inch motors?

According to my thermal gun, it's at least 285 F, even after very short trips. Is this too hot for the com end?

I added extra cooling fans, and it didn't seem to help. The motor runs fine, but some of the number I saw scared me (315F+)


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## major (Apr 4, 2008)

PZigouras said:


> Does anyone know what the recommended arm temp is on the comm side of the ADC 8-inch motors?
> 
> According to my thermal gun, it's at least 285 F, even after very short trips. Is this too hot for the com end?
> 
> I added extra cooling fans, and it didn't seem to help. The motor runs fine, but some of the number I saw scared me (315F+)


Class H is 180ºC.


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## PZigouras (Jun 5, 2010)

180 C is just over 350 F... which only gives me about a 40 or 50 degree margin until you get to the insulation's rating. I'm not sure how I feel about that.

Is the insulation rating the maximum temp, or is it the operating temp?


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## major (Apr 4, 2008)

PZigouras said:


> 180 C is just over 350 F... which only gives me about a 40 or 50 degree margin until you get to the insulation's rating. I'm not sure how I feel about that.
> 
> Is the insulation rating the maximum temp, or is it the operating temp?





> Insulation systems are rated by standard NEMA (National Electrical Manufacturers Association) classifications according to maximum allowable operating temperatures:
> Temperature Tolerance ClassMaximum Operation
> Temperature AllowedAllowable Temperature Rise at full load
> 1.0 service factor motor 1)Allowable
> ...


credit: http://www.engineeringtoolbox.com/nema-insulation-classes-d_734.html


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## major (Apr 4, 2008)

PZigouras said:


> Does anyone know what the recommended arm temp is on the comm side of the ADC 8-inch motors?
> 
> According to my thermal gun, it's at least 285 F, even after very short trips. Is this too hot for the com end?
> 
> I added extra cooling fans, and it didn't seem to help. The motor runs fine, but some of the number I saw scared me (315F+)


Hey PZig,

I assume this hot motor is on the receiving end of one of your "controllers". Have you considered that your controller may be the reason that the motor is running hotter than what you would normally expect?

Just sayin,

major


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## PZigouras (Jun 5, 2010)

major said:


> Hey PZig,
> 
> I assume this hot motor is on the receiving end of one of your "controllers". Have you considered that your controller may be the reason that the motor is running hotter than what you would normally expect?
> 
> ...


 
I've tried the motor both on a Logisystems and an EP-1000, and it still did the same thing. 

I even put a large snubber (80uf) across the motor terminals -- hoping that it would smooth out the chop -- and it didn't help.

The EP-1000 runs at 136Hz, so I thought that the lower frequency would help. Would the frequency even have an affect on motor temp?

I'm running 120 volts. I could wire it for 240, which would cut the current in half, but that won't help the armature temp (as far as I know). And the controller already runs cold, so I don't see any benefit of wiring it for 240 right now.


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