Electrical Machines If starting current of a 3 - Φ induction motor is 5 times the rated current, while rated slip is 4 %, then ratio of starting torque to full load torque is 0.6. 1. 0.8. 0.4. 0.6. 1. 0.8. 0.4. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Armature reaction in a DC machine is in direct opposition to the main poles. is in the same direction as the main poles. makes an angle with the main pole axis which is load dependent. makes an angle of 90° with the main pole axis. is in direct opposition to the main poles. is in the same direction as the main poles. makes an angle with the main pole axis which is load dependent. makes an angle of 90° with the main pole axis. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the efficiency when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 78.5% 72.5% 82.5% 67.5% 78.5% 72.5% 82.5% 67.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In Ward-Leonard system, the lower limit of the speed imposed by Field resistance. Residual magnetism of the generator. Armature resistance. None of above. Field resistance. Residual magnetism of the generator. Armature resistance. None of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Exciting current of an induction motor is none of these. higher than power transformer. lesser than power transformer. equal as power transformer. none of these. higher than power transformer. lesser than power transformer. equal as power transformer. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the frequency of a alternator, if P = number of poles and N = revolution made per second? 120N / P Hz. 120 / PN Hz. 120P / N Hz. PN / 2 Hz. 120N / P Hz. 120 / PN Hz. 120P / N Hz. PN / 2 Hz. ANSWER DOWNLOAD EXAMIANS APP
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