Electrical Machines R1 is the resistance of the primary winding of the transformer. The turn ratio in terms of primary to secondary is K. Then the equivalent resistance of the primary referred to secondary is K×R1 R1 /K² K²R1 R1 /K K×R1 R1 /K² K²R1 R1 /K ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Resistance commutation is used generally in case of None of these fractional kW DC machines. DC machines bellow 5 kW. DC machines above 10 kW. None of these fractional kW DC machines. DC machines bellow 5 kW. DC machines above 10 kW. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For a practical synchronous motor the pull out torque will occur when the torque angle is nearly equal to 30°. 0°. 75°. 45°. 30°. 0°. 75°. 45°. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3- phase synchronous motor can operate over a wide range of power factors i.e. from lagging to leading power factor. This is achieved by changing the field excitation. changing the load. varying the applied voltage. varying the speed. changing the field excitation. changing the load. varying the applied voltage. varying the speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the mechanical power developed by a DC series motor is maximum? Back emf is equal to zero. Back emf is equal to half the applied voltage. None of above. Back emf is equal to applied voltage. Back emf is equal to zero. Back emf is equal to half the applied voltage. None of above. Back emf is equal to applied voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Under which of the following conditions hunting of synchronous motor is likely to occur ? Small and constant load. Over-loading for long period. Periodic variation of load. Over-excitation. Small and constant load. Over-loading for long period. Periodic variation of load. Over-excitation. ANSWER DOWNLOAD EXAMIANS APP
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