Electrical Machines An auto transformer having a transformation ratio of 0.8 supplies a load pf 10 KW. The power transfered inductively from the primary to secondary is 10 KW. 2 KW. 8 KW. 0. 10 KW. 2 KW. 8 KW. 0. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The flux involved in the emf equation of a transformer has maximum value. total value. average value. rms value. maximum value. total value. average value. rms value. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the necessity of copper brushes in a dc motors? None of these. To increase the flux cutting by the rotor. To convert alternating supply current to direct current. To absorb the mechanical shocks produced during running condition. None of these. To increase the flux cutting by the rotor. To convert alternating supply current to direct current. To absorb the mechanical shocks produced during running condition. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines DC motors are stopped by opening line switches and not by forcing the handle of the motor starter back to OFF position. This is due to occurance of None of these. Both of above. Heavy sparking at the first stud of starting resistance steps. Heavy sparking at brushes. None of these. Both of above. Heavy sparking at the first stud of starting resistance steps. Heavy sparking at brushes. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines φA 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 speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 920 RPM 940 RPM 960 RPM 970 RPM 920 RPM 940 RPM 960 RPM 970 RPM ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 500 V, 120 KW, 50 Hz, star connected synchronous motor operating at 0.8 power factor leading has full load efficiency of 91%. The armature resistance is equal to 0.08Ω. The magnitude of armature current is nearly equal to 127 A. 173 A. 190 A. 240 A. 127 A. 173 A. 190 A. 240 A. ANSWER DOWNLOAD EXAMIANS APP
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