Electrical Machines When a short circuit test on a transformer is performed at 25 V, 50 Hz, the drawn current is I1. If the test is performed by 25 V and 25 Hz and power drawn current is I2, then I1 < I2 I1 = I2 None of these I1 > I2 I1 < I2 I1 = I2 None of these I1 > I2 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC Motor is driving a constant load torque having armature resistance of 0.25 Ω and armature current of 60 A having connected to a voltage of 230 V. Now a resistance of 1 ohm is added into the armature circuit. The ratio of their speed will be 0.62. 1.24. 0.25. 0.72. 0.62. 1.24. 0.25. 0.72. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC Shunt Motor the speed can be increased by Increasing the field current. Increasing the field current. Increasing the armature current. Decreasing the field current. Increasing the field current. Increasing the field current. Increasing the armature current. Decreasing the field current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In V/f speed control of 3-phase induction motor, with increase in frequency, the slip at which maximum torque occurs increase. either of these. None of these decrease. increase. either of these. None of these decrease. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When maximum flux density is constant, the eddy current losses are proportional to f V f2 V2 f V f2 V2 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding dc machines : 1. possible resistance of shunt-field winding is 1 Ω 2. possible resistance of series-field winding is 1 Ω 3. electrographite brushes are used for 230 V, 10 A machines 4. Copper-graphite brushes are used for 230 V, 10 A machines 5. Possible armature-circuit resistance is 1 Ω From these, the correct statements are 2, 4 ,5 1, 4 2, 3 , 5 1, 3, 5 2, 4 ,5 1, 4 2, 3 , 5 1, 3, 5 ANSWER DOWNLOAD EXAMIANS APP
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