Electrical Machines If s is the slip and f is the supply frequency of an induction motor, the frequency of rotor current is given by sf / 2. sf. f / s. s2. sf / 2. sf. f / s. s2. 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 2, 3 and 4 1, 2 and 4 1 and 3 1, 2, and 3 2, 3 and 4 1, 2 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC machine the armature mmf is rotating with respect to field poles as well as armature. rotating with respect to field poles. stationary with respect to field poles. stationary with respect to armature. rotating with respect to field poles as well as armature. rotating with respect to field poles. stationary with respect to field poles. stationary with respect to armature. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If in a sub – station there is one 132 / 33 kV transformer whose secondary is connected with primary of one 33 / 11 kV transformer, the total transformation ratio of the sub – station will be, 7. 12. 4. 3. 7. 12. 4. 3. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In above question, find rms line voltage for delta connection? 100 V. 50 V. 230.2 V. 399 V. 100 V. 50 V. 230.2 V. 399 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The field divertor resistance for a DC series motor is of order of 100 Ω 50 Ω 10 Ω 0.1 Ω 100 Ω 50 Ω 10 Ω 0.1 Ω ANSWER DOWNLOAD EXAMIANS APP
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