DC Motor MCQs

For a dc motor operating under condition of maximum transfer of power, the efficiency of the motor is

The speed of a dc shunt motor is required be more than full load speed. This may be achieved by

If the field circuit of a loaded shunt motor s suddenly opened

If the load current and flux of a dc motor are held constant and voltage applied across are held constant and voltage applied across its armature is increased by 10 per cent, its speed will

Under constant load condition, the speed of a dc motor is effected by

The brush voltage drops in dc in / of the order of

A dc shunt motor has external resistance R1 in the field circuit and resistance R2 in the armature circuit. The starting armature current for the motor will be minimum when

If the supply voltage to a shunt motor is increased by 25%, which of the following will decrease?

In a dc machine dull yellow spark indicates

The output power of any electrical motor is taken from