Thursday, May 22, 2014

Effect of Environment on Induction Motor

Effect of Environmental factors on Rating of Machines:-
Every machine is designed to operate under some designed environmental aspects if there are variations in these conditions then machine performance parameters will change accordingly.
There are so many examples for the same below is example for the same:-
Effect of Temperature:-
A 100 KW motor of intermittent rating might able to deliver 200 KW if continuously operated at the north pole where ambient temperature is -80 degree Celsius, as heat generated during motor running is not sufficient to overheat the motor under these ambient conditions.
Similarly when motors are operated under high temperature condition motors rating will get reduced.


Effect of altitudes:-
At high altitudes air density is low and which will decrease the cooling effect of motor. This limit is negligible for elevations less than 1000 m above sea level.

For heights greater than 1000m the rating of machine should be reduced accordingly as per table shown below:-


Sr. No.
Height above sea level (m)
Rating Percent
Rating Percent


Speed up to 1000 RPM
Speed Above 1000 RPM
1
0-      1000
100
100
2
2000
95
92
3
3000
90
85
4
4000
85
72
Effect of Humidity:-
Humidity also effect the performance of machine or induction motor. As high humidity will leads to lower life of induction motors. As Humidity may enter the motor and same is get absorbed by motor insulation leads to lower life of motor. High moisture content will leads to corrosion of metal parts.