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 K²R1 R1 /K² K×R1 R1 /K K²R1 R1 /K² K×R1 R1 /K ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Synchronising power of a synchronous motor varies inversely as 1/Xs All of these directly as synchronous reactances Xs directly as Xs2 inversely as 1/Xs All of these directly as synchronous reactances Xs directly as Xs2 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the effect of armature reaction ? None of the options. Armature flux distorts the main field flux. Armature flux weakens the main field flux. Both option B and C. None of the options. Armature flux distorts the main field flux. Armature flux weakens the main field flux. Both option B and C. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3-φ alternator has negligible stator resistance. A short circuit test is conducted on this alternator. At a particular speed, a field current of If1 is required to drive the rated armature current. If the speed of the alternator is reduced to half, the field current required to maintain rated armature current Would be equal to If1/2. Would be equal to If1. Woud be equal to 2If1. Cannot be predicted due to insufficient data. Would be equal to If1/2. Would be equal to If1. Woud be equal to 2If1. Cannot be predicted due to insufficient data. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The maximum power developed in cylindrical synchronous machine is occurs at a load angle of Greater than 90o. 0o. less than 90o. 90o. Greater than 90o. 0o. less than 90o. 90o. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following methods of speed control is not affected through stator side? Change of supply frequency. Change of supply voltage. Change of rotor resistance. Change of number of pole. Change of supply frequency. Change of supply voltage. Change of rotor resistance. Change of number of pole. ANSWER DOWNLOAD EXAMIANS APP
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