Motor is heating up??

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...."This is also why it is not a good idea to let a pump run with a discharge valve closed. The energy that goes into the water to produce pressure also produces heat and since there is no flow the heat cannot be dissipated, the end result can be a very hot pump indeed."
I just did some reading on "head" and pressure to better understand what you're refering to. This seems to explain it pretty well I believe...sound accurate Sahib?
 
Is it TEFC? Is the fan turning? Is it damaged? Can you feel any airflow around the cooling fins.

I agree that there may be actually nothing wrong with it. We have a motor at our plant that is hot to touch. You can touch it but not leave your hand on it for more than a few minutes.
 
jahilliard said:
...."This is also why it is not a good idea to let a pump run with a discharge valve closed. The energy that goes into the water to produce pressure also produces heat and since there is no flow the heat cannot be dissipated, the end result can be a very hot pump indeed."I just did some reading on "head" and pressure to better understand what you're refering to. This seems to explain it pretty well I believe...sound accurate Sahib?
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Yes. During normal operation of pump, only around 10% heat loss in motor. When discharge valve closed, around 30% heat loss.
 
typical pump curve fwiw

who knows without being on site, may be something totally stupid like the marathon pump was not providing enough flow (cause maybe running BACKWARDS, wrong rotation, hence low power), then new pump/motor added due to low flow and it is now doing 90% of the work?

centrifugal-pump-fundamental-oil-and-gas-6-638.jpg
 
It will turn for a second (or a fraction thereof) till it dead heads, then absolutely correct! The heaters trip the OLs. So, if the overloads are sized correctly, why aren't they tripping? If it's pulling enough amps to make the frame that hot, something gotta give! Whats the temp rating of this motor? How many amps is it drawing? Duty rating, service factor!
I just dunno. I've got close to 500 3 phase motors here, from fractional to 200 hp, they rarely get too hot to touch (well, maybe the kiln fan motors, but they're 90C motors) unless there's bearings going out, or somethings binding somewhere.
 
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OP, you need pictures of each nameplate; there are too many unknowns here.

What are the cooling classes of the motors? Unless they are both TENV there should be active air cooling on each. A malfunction there would definitely leave you with a hotter frame temperature.
 
The OP should check by thermometer or by resistance measurement of motor winding whether temperature has exceeded rated winding insulation temperature. Because for every 10 degree C rise in temperature, winding insulationrated life reduces by half.
 
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