If a D.C. motor is to be selected for conveyors, Series motor would be preferred.
Answer : D.C. Series motor is generally preferred for cranes and hoists.
Answer : Cumulative compound D.C. motor is preferred for elevators.
Answer : If the centrifugal switch does not open at 70 to 80 percent of synchronous speed of motor, it would result in damage to the starting winding.
Answer : 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 derated by a factor recommended by manufacturer and select the next higher H.P. motor.
Answer : In a D.C. series motor, if the armature current is reduced by 50%, the torque of the motor will be equal to 25% of the previous value.