Electrical Machines A 4-pole dc generator runs at 1500 rpm. The frequencyof current in the armature winding is 100 Hz 50 Hz 25 Hz 0 Hz 100 Hz 50 Hz 25 Hz 0 Hz ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For successful parallel operation of two single phase transformers, the most essential condition is that their polarities are properly connected turn- ratios are exactly equal KVA ratings are equal percentage impedances are equal polarities are properly connected turn- ratios are exactly equal KVA ratings are equal percentage impedances are equal ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines At slip s = 1 torque developed in machine is maximum torque. none. starting torque. electromagnetic torque. maximum torque. none. starting torque. electromagnetic torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If Pi and Pc represent core and full load copper loss respectively, the maximum KVA delivered to load corresponding to maximum efficiency is equal to rated KVA is (Pi/Pc)2 Pc/Pi Pi/Pc √(Pi/Pc) (Pi/Pc)2 Pc/Pi Pi/Pc √(Pi/Pc) ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The speed regulation of a DC motor is given as (NfL − NnL)/NnL. NnL/NfL. (NnL − NfL)/NfL. NnL − NfL. (NfL − NnL)/NnL. NnL/NfL. (NnL − NfL)/NfL. NnL − NfL. 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 3.1 Ω 2 .1 Ω 1.79 Ω 1.8 9 Ω 3.1 Ω 2 .1 Ω 1.79 Ω 1.8 9 Ω ANSWER DOWNLOAD EXAMIANS APP
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