Electrical Machines A 3 - Φ induction motor draws an current of 50 A from mains when starts by direct switching. If an auto transformer with 60 % tapping is used for starting the current drawn from the mains will be 36. 50. 18. 80. 36. 50. 18. 80. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In star-delta starting of squirrel cage induction motor compared to DOL starting the starting current and torque are 1/√3, 1/3 1/√3, 1/√3 1/3, 1/3 1/3, 1/√3 1/√3, 1/3 1/√3, 1/√3 1/3, 1/3 1/3, 1/√3 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, 3, 5 1, 4, 6 1, 2, 5 1, 2, 6 1, 3, 5 1, 4, 6 1, 2, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For a 3-phase, 4 pole, 50 Hz synchronous motor the frequency, pole number and the frequency are halved. The motor speed will be 1500 rpm 375 rpm 75 rpm 3000 rpm 1500 rpm 375 rpm 75 rpm 3000 rpm ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following induction motor has the highest starting torque? Squirrel cage induction motor. Same in both induction motors. Slip ring induction motor. None of these Squirrel cage induction motor. Same in both induction motors. Slip ring induction motor. None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The power factor of squirrel cage induction motor is low at light loads only both A and B low at rated load only low at heavy loads only low at light loads only both A and B low at rated load only low at heavy loads only ANSWER DOWNLOAD EXAMIANS APP
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