Electrical Machines When R2 is rotor resistance, X2 the rotor reactance at supply frequency and s the slip, then the condition for maximum torque under running condition will be sR2 = X2. R2 = s2X2. R2 = s2X2. R2 = sX2. sR2 = X2. R2 = s2X2. R2 = s2X2. R2 = sX2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two generators operating in parallel with rating 50MW and 100MW respectively. Both their respective governor settings are identical as 4%, consider same no load frequency. How will the machine share a common load of 100 MW 33.33 MW and 66.67 MW respectively 50 MW and 50 MW respectively any of the above 66.67 MW and 33.33 MW respectively 33.33 MW and 66.67 MW respectively 50 MW and 50 MW respectively any of the above 66.67 MW and 33.33 MW respectively 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, 4, 6 1, 2, 5 1, 3, 5 1, 2, 6 1, 4, 6 1, 2, 5 1, 3, 5 1, 2, 6 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a synchronous motor when the rotor speed exceeds the synchronous speed during hunting negative sequence currents are generated. the damper bars develop induction motor torque. the damper bars develop induction generator torque. the damper bars develop synchronous motor torque. negative sequence currents are generated. the damper bars develop induction motor torque. the damper bars develop induction generator torque. the damper bars develop synchronous motor torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If an additional resistance is connected in series with a DC motor operating at rated speed, the speed of the motor will Reduce. Increase. Remain unaltered. Oscillate around the normal speed. Reduce. Increase. Remain unaltered. Oscillate around the normal speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For a single phase capacitor start induction motor which of the following is valid? Rotation can be changed by interchanging supply terminals. None of these. Rotation can be changed by reversing main winding terminals. Direction of rotation cannot be changed. Rotation can be changed by interchanging supply terminals. None of these. Rotation can be changed by reversing main winding terminals. Direction of rotation cannot be changed. ANSWER DOWNLOAD EXAMIANS APP
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