Question Bank for Electrical Machine-I.

Page: 03

1. For a commutator machine with 6 poles and 40 coils, determine for a simplex lap winding:
2. A 100 kW, 200 V D.C shunt generator has R_a = 0.050 ohm. and R_F = 50 ohm. If the generator operates at rated voltage, calculate the induced voltage at (Neglect brush contact drop.)
3. A 200 V DC shunt motor takes 22A at rated voltage and runs at 1000 rpm. Its field resistance is 100 ohm. and armature circuit resistance including brushes is 0.1 ohm. Calculate the value of additional resistance required in armature circuit to reduce speed to 800 rpm when-
4. Explain armature reaction and its ill effects in D.C machine. How compensating winding and interpoles reduces armature reaction.
5. Derive emf equation for voltage generated in a D.C generator. Derive torque equation for torque generated in D.C machine.