Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again field winding must be excited by low voltage dc supply the field winding connection must be reversed the armature connection must be reversed the field winding must be replaced field winding must be excited by low voltage dc supply the field winding connection must be reversed the armature connection must be reversed the field winding must be replaced ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The compensating winding in a DC machine is located on commutating poles for improving commutation. is located on pole shoes to avoid the sparking at the brushes. is located on pole shoes for avoiding the flashover at the commutator. is located in armature slots for compensation of the armature reaction. is located on commutating poles for improving commutation. is located on pole shoes to avoid the sparking at the brushes. is located on pole shoes for avoiding the flashover at the commutator. is located in armature slots for compensation of the armature reaction. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC motor with armature resistance of 0.5 ohms is connected directly to a 230 Volt supply. If the armature is stationary then the current flowing through armature is 250 A. 570 A. 340 A. 460 A. 250 A. 570 A. 340 A. 460 A. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature of DC machine is made of silicon steel lamination to increase the permeability. reduce both eddy current and hysteresis loss. reduce hysteresis loss only. reduce eddy current loss only. increase the permeability. reduce both eddy current and hysteresis loss. reduce hysteresis loss only. reduce eddy current loss only. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a star - delta starting of an IM reduced voltage is applied to the stator. resistance is inserted in the rotor. line voltage is 57.7 % of stator voltage. applied voltage per stator phase is 57.7 % of a line volt reduced voltage is applied to the stator. resistance is inserted in the rotor. line voltage is 57.7 % of stator voltage. applied voltage per stator phase is 57.7 % of a line volt ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3 - Φ, 4 pole IM is supplied from a 50 Hz source. Calculate rotor frequency when rotor runs 600 rpm? 20 Hz. Can be determined. 35 Hz. 30 Hz. 20 Hz. Can be determined. 35 Hz. 30 Hz. ANSWER DOWNLOAD EXAMIANS APP
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