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Amol Jadhav
12-04-2013 12:02 AM

Motor Space Heater requirement !

Is there specific guarantee requirement if motor need to operate with high Ambient vAariations>-29 to + 45 degree... Is IP55 and above motor can cause condensation or not.
12-04-2013 02:38 AM
Top #2
Poonsak Klintip
12-04-2013 02:38 AM
Yes, depend on sizing of motor must require, see in standard IEC or IEEE.
12-04-2013 05:09 AM
Top #3
Michael Wright, P.Eng., CMRP
12-04-2013 05:09 AM
Motors of this type "breath" and as they cool down after a shut-down, they can suck in warm, moist air which will then cause condensation inside the windings if the motor cools below the dew point of the air inside it. Therefore winding heat will be required. As an aside, the windings themselves can be used as a heating element if a low voltage 1-phase AC is applied to them when they are shut down. If you take this approach, you must ensure that all applicable codes and regulations are followed as well as ensuring that appropriate safety interlocks are engineered into the design. The system with which I was familiar was a 600V 3-phase squirrel cage motor that was supplied 24V 1-p when it was shut down. This provided a current of about 25% of full load rating and used the iron and copper losses as the heater element.
12-04-2013 08:05 AM
Top #4
Eric Stark
12-04-2013 08:05 AM

This approach of supplying current when motor is idle is very common. I integrated Low-Voltage DC into large motors in a humid/cold environment instead of space heaters (which are a pain in the neck).

Hope it helped,

Eric Stark 
12-04-2013 10:15 AM
Top #5
12-04-2013 10:15 AM
Motor space heater is used without any adverse consequences worldwide,and is a proved in technology for motors upto 18.2MW 11KV I had commissioned so far.
Injecting DC may create unwaranted magnetisation in the cores and have not seen any International papers on this.
Injecting single phase supply is not understood and may create winding damage due to single phasing too,anyway if there is any international research papers on bith the subjects ie DC injection/1ph ac injection would like to get updated.
12-04-2013 12:58 PM
Top #6
Harri Vihriälä
12-04-2013 12:58 PM
I would comment here that separate space heater is mandatory. period. If the location is very humid you may have to use a more powerful heater. For the cold anvironment please check that the steel used is suitable for this cold temperatures.
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