Shunt motors, Series motors, Compound motors
Answer : During rheostat braking of D.C. series motors motor is run as a generator.
Answer : Plugging method of braking is generally used in elevators.
Answer : Regenerative method of braking is based on that back e.m.f. is equal to the applied voltage.
Description : Explain the necessity of starter for D.C. motor. State various types of D.C. motor starter.
Answer : Necessity of Starter for D.C. Motor: Armature current is given by equation Ia = (V−Eb)/Ra i) If the motor is at standstill or rest, back emf Eb is zero (as Eb= ZNP/(60A), at start speed N ... . Types of D.C. motor starters: i) Two point starter ii)Three point starter iii) Four point starter
Description : State at least one function and the material used for the following parts of DC Motor.
Answer : Part Function Material Yoke -Provides mechanical support for poles -Acts as protecting cover for machine -Provides path for magnetic flux Cast Iron OR Cast Steel Field Winding - ... Pole core Provides mechanical support to field winding. Cast Iron OR Cast Steel