Electrical Machines In a DC generator sparking between brushes and commutator surface may be due to under commutation. too rapid reversal of current. any of the above. over commutation. under commutation. too rapid reversal of current. any of the above. over commutation. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following factors improve commutation in a dc machine ? 1. High contact resistance of brushes 2. High inductance of the coils undergoing commutation 3. Shifting of brushes in the direction of rotation for a generator and in the opposite direction For a motor 4. Narrow width for the commutation bars Select the correct answer using the codes given below : Codes : 1 and 3 1, 2, and 3 1, 2 and 4 2, 3 and 4 1 and 3 1, 2, and 3 1, 2 and 4 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of following DC generator will be in a position to build up without any residual magnetism in the field? Series. Separately excited. Compound. Shunt. Series. Separately excited. Compound. Shunt. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3-phase, alternator has generated emf per phase of 230 V with 10% 3rd harmonic and 6% 5th harmonic content. Calculate rms line voltage for star connection. 100 V. 230.2 V. 399 V. 50 V. 100 V. 230.2 V. 399 V. 50 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When an electric train is moving down a hill, the DC motor will operate as DC series motor. DC shunt motor. DC series generator. DC shunt generator. DC series motor. DC shunt motor. DC series generator. DC shunt generator. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which type of motors are used for lathes? Synchronous motor. Cage induction motor. DC shunt motors. Either A or B. Synchronous motor. Cage induction motor. DC shunt motors. Either A or B. ANSWER DOWNLOAD EXAMIANS APP
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