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, 5
 1, 2, 6
 1, 3, 5
 1, 4, 6

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Electrical Machines
A DC shunt generator builds up to a voltage of 220 V at no load while running at its rated speed. If the speed of the generator is raised by 25% kepping the circuit conditions unaltered, then the Voltage to which the machine would build up will

 increase to value lying between 220 V and 1.25 times 220 V
 increase to 1.25 times 220 V
 not change and remain at 220 V
 increase to a value greater than 1.25 times 220 V

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Electrical Machines
In a transformer

 both OC and SC tests are conducted on LV side
 OC test is conducted on LV side and SC test is conducted on HV side
 OC test is conducted on HV side and SC test is conducted on LV side
 both Oc and SC tests are conducted on HV side

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