DC Motors
If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambient temperature, then the motor

Is to be de-rated by a factor recommended by manufacturer and select the next higher H.P. motor
Can be used for 50°C ambient temperature also
Of higher H.P. should be selected
Of lower H.P. should be selected

ANSWER DOWNLOAD EXAMIANS APP

DC Motors
In variable speed motor

A stronger commutating field is needed at low speed than at high speed
Same commutating field is needed at low speed than at high speed
None of these
A weaker commutating field is needed at low speed than at high speed

ANSWER DOWNLOAD EXAMIANS APP