Electrical Machines An induction motor has a rotor resistance of 0.002 Ω / phase. If the resistance is increased to 0.004 Ω / phase then the maximum torque will reduced to half increase by 100% increase by 200% remain unaltered reduced to half increase by 100% increase by 200% remain unaltered ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding the speed control of dc motors : 1. ward-leonard method is suitable forconstant-torque drives 2. Ward-leonard method is suitable for constant-power drives 3. field-control method facilitates speed control below base speed 4. Armature-resistance control method is more efficient than ward-leanard method 5. Field-control method is suitable for constant-torque drives 6. Armature-resistance control method is suitable for constant-torque drives From these, the correct answer is 1, 2, 6 1, 4, 6 1, 2, 5 1, 3, 5 1, 2, 6 1, 4, 6 1, 2, 5 1, 3, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a 3 - Φ IM in order to eliminate cogging the number of stator slots must be unequal to number of rotor slots and skewed in shape. either (B) or (C). an integral multiple of number of rotor slots. equal to number of rotor slots. unequal to number of rotor slots and skewed in shape. either (B) or (C). an integral multiple of number of rotor slots. equal to number of rotor slots. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Ward-Leonard system for controlling the speed of a DC motor is used where The accuracy in speed control is required. Very fine speed control over the whole range from zero to normal speed is required. The speed in both the direction is required. All of above. The accuracy in speed control is required. Very fine speed control over the whole range from zero to normal speed is required. The speed in both the direction is required. All of above. ANSWER DOWNLOAD EXAMIANS APP
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 None of these I1 < I2 I1 = I2 I1 > I2 None of these I1 < I2 I1 = I2 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 220 V DC machine has an armature resistance 1 Ω. If the full load current is 20 A, the difference of induced voltage between generator and motor is 0 V. 20 V. 60 V. 40 V. 0 V. 20 V. 60 V. 40 V. ANSWER DOWNLOAD EXAMIANS APP
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