GATE EE 2021 : Electrical Machines Quiz 3 (App update required to attempt this test)

The armature core of a dc machine is laminated to minimize

If same machine is wound for LAP and wave windings then power rating will be -

A permanent magnet DC commutator motor has a no-load speed of 4500 rpm when connected to 150 V DC supply. The armature resistance is 2 Ω and neglect the other losses. Find the speed of motor when motor is supplying from 100 V DC and developing torque of 2 N-m?

A DC shunt motor having unsaturated magnetic circuit runs at 1000 rpm with rated voltage. If the applied voltage is half of the rated voltage the motor will run at:

A cumulative compound long shunt motor is driving a load at rated torque and rated speed. If the series field is shunted by a resistance equal to the resistance of the series field, keeping the torque constant.

A 230 V DC series motor develops its rated output at 1500 rpm while taking 20A. Armature and series field resistance are 0.3ohm and 0.2ohm respectively. Neglect saturation, Resistance that must be added to obtain a rated torque at 1000 rpm is_____ ohm.