Electrical Machines Find the number of poles required, when the frequency is 50Hz and speed of the motor is 500 rpm? 5 24 12 10 5 24 12 10 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be 59.2%. 88.8%. 57.1%. 48.0%. 59.2%. 88.8%. 57.1%. 48.0%. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following methods are used to control the speed of DC motors is field current control All of these supply voltage control armature circuit resistance control field current control All of these supply voltage control armature circuit resistance control ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A single-phase transformer has its maximum efficiency at 60 percent of full load. At full load copper loss will be more than core loss. zero. equal to core loss. less than core loss. more than core loss. zero. equal to core loss. less than core loss. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To have sparkless commutation, the armature reaction effect in a DC machine is neutralized by shifting the brush axis from GNA to MNA. compensating winding and commutating poles. increasing field excitation. fixing the brush axis inline with the pole axis. shifting the brush axis from GNA to MNA. compensating winding and commutating poles. increasing field excitation. fixing the brush axis inline with the pole axis. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To eliminate 5th harmonic in the induced voltage phase breadth should be 30° 36° 18° 72° 30° 36° 18° 72° ANSWER DOWNLOAD EXAMIANS APP
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