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 173 A. 240 A. 190 A. 127 A. 173 A. 240 A. 190 A. 127 A. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A shunt generator has a critical field resistance of 300 Ω at a speed of 800 rpm if the speed is raised to 1000 rpm the critical field resistance is 145 Ω. 150 Ω. 375 Ω. 225 Ω. 145 Ω. 150 Ω. 375 Ω. 225 Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 220 V, DC shunt motor is operating at a speed of 1440 rpm. The armature resistance is 1.0 Ω and armature current is 10 A. of the excitation of the machine is reduced by 10%, the extra resistance to be put in the armature circuit to maintain the same speed and torque will be 1.8 9 Ω 3.1 Ω 1.79 Ω 2 .1 Ω 1.8 9 Ω 3.1 Ω 1.79 Ω 2 .1 Ω ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the temperature of armature resistance is increased, the speed of a series motor would not change. increase. decrease. None of above. not change. increase. decrease. None of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Commutator pitches of duplex and simplex lap windings are respectively 4 and 2 2 and 2 4 ang 1 2 and 1 4 and 2 2 and 2 4 ang 1 2 and 1 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Due to magnetic saturation, the flux per pole in a DC machine without brush shift increases in both the generators and the motors with load. increases in generators but decreases in motor with load. decreases in both generators and the motors with load. decreases in generators and increases in motor with load. increases in both the generators and the motors with load. increases in generators but decreases in motor with load. decreases in both generators and the motors with load. decreases in generators and increases in motor with load. ANSWER DOWNLOAD EXAMIANS APP
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