I am very confused about the situation of this motor. It is over heating and I am not sure what to do at this point. The temp rating of the motor is 140 deg. F. and it is at 177. The current is at its nameplate. Its service factor is 1.15. Its a 3 phase 208 and the voltage is fine. I don't see the voltage or the current being the reason for the the motor getting so hot. If the current is ok then what else is there that would cause the motor to get hot like that. Doesn't everything point to a rise in current and thus overheating of the motor.
Chilled water pump
- Thread starter JdoubleU
- Start date
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- Location
- Massachusetts
Jakewhis said:
Isn't the 140 deg. F the amount of temp rise not the actual temp rating?
70 F room + 140 F rise = 210 F acceptable.
HighWirey
Senior Member
- Location
- Cocoa, Florida, USA
Jakewhis said:
Why do you say your motor is overheating? Because it feels hot. or shutting down because of temperature?
Some motors and transformers get 'really hot' by our perception. However considering the temperature rise, they are perfectly happy.
Best Wishes Everyone
weressl
Esteemed Member
iwire said:
The temp rise would most likely to be given in Centigrades, not Farenheit. The rise refers to the maximum WINDING temperature, not the surface temerature of the motor. You can only determine the winding temperature by the resistance method.
HighWirey
Senior Member
- Location
- Cocoa, Florida, USA
Jakewhis said:
Feeling and smelling are not related to the real centigrade scale. Did your motor go out on over temperature, or just on your smell? It sounds like your Mr Motor is just a 'hot happy camper'.
Best Wishes Everyone
- Location
- Massachusetts
weressl said:
But he was there and tells us the label is in Fahrenheit.
Have you seen a motor with a 'max' temp rating 140 deg. F?
I have not, 140 F ain't even warm.
Or you could stick a laser temp prob in the end and get a pretty close approximation.
weressl
Esteemed Member
iwire said:
Nope. The hot spot is inside the slot. Even if it is an open motor with the end-turns visible, the temperature is consdierably less than in the stator slots.
Laser temp probe? I think the laser is only used for aiming IR sensors, not to perform the actual temperature measurements, unless you talking about a technology I am not familiar with.
HighWirey
Senior Member
- Location
- Cocoa, Florida, USA
weressl said:
Yes sir,
The laser diode on the cheepies is used only for aiming. Be carefull men, as those 'laser temp probes' will lead you down 'that primrose path'.
Best Wishes Everyone
IMM_Doctor
Senior Member
FLA and Emmisivity
FLA and Emmisivity
I would get very accurate actual motor amperage readings during runtime.
And you want to make sure your motor is thermally protected via internal means, or external overload detection.
If you find the actual motor amperage exceeding nameplate readings, the easiest way to reduce is to throttle back on the intake (suction line). Many times there is a 90deg ball valve on the inlet of the pump for servicing purposes. You can close this valve a few degrees while watching your ampmeter. (Don't close the valve so much to cavitate or starve the pump however). If this provides a solution, you will want to mechanically limit the stroke of the valve permanently or post signage, sot that subsequent service technicians don't open the valve fully in the future.
Also, agree with other responses, IR temperature measurment can only be taken if you are trained to do so. The "casual" IR measurment is good for relative comparisons, as an example checking the terminal lugs of a motor starter or circuitbreaker, and comparing L1 vs L2 vs L3.
Using IR to actually quantify a temperature you must be aware of Emmisivity settings on your IR instrument. Emmisivity is a function of the COLOR of the object that you are trying to obtain the IR temperature reading from.
FLA and Emmisivity
I would get very accurate actual motor amperage readings during runtime.
And you want to make sure your motor is thermally protected via internal means, or external overload detection.
If you find the actual motor amperage exceeding nameplate readings, the easiest way to reduce is to throttle back on the intake (suction line). Many times there is a 90deg ball valve on the inlet of the pump for servicing purposes. You can close this valve a few degrees while watching your ampmeter. (Don't close the valve so much to cavitate or starve the pump however). If this provides a solution, you will want to mechanically limit the stroke of the valve permanently or post signage, sot that subsequent service technicians don't open the valve fully in the future.
Also, agree with other responses, IR temperature measurment can only be taken if you are trained to do so. The "casual" IR measurment is good for relative comparisons, as an example checking the terminal lugs of a motor starter or circuitbreaker, and comparing L1 vs L2 vs L3.
Using IR to actually quantify a temperature you must be aware of Emmisivity settings on your IR instrument. Emmisivity is a function of the COLOR of the object that you are trying to obtain the IR temperature reading from.
brian john
Senior Member
- Location
- Leesburg, VA
Emissivity is a function of how reflective an object is, now color does play into this but two objects of the same color can reflect differently and therefore have a different emissivity. Polished aluminum compared to brushed aluminum, glossy black compared to flat black.
1. Amp the motor.
2. Meg the motor.
3. Check flow rates compared to what the expected flow rate is/was.
4. Do vibration analysis.
5. Take reference temperature at an identified hot spot for future reference, note ambient.
6. If this is a critical pump check for availibility of replacement.
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Make sure someone is not over greasing the motor, this will give you the temp increase and smell if the grease get down towards the windings. I have three motors that when the operators grease them you will get a temp alarm. After testing all the temp system the only common factor was a work order to grease the motors. A little goes a long way with grease in windings.
GC
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