Question: The angle between the rotating stator flux and rotor poles is called _________ angle.

• 1. synchronizing
• 2. obtuse
• 3. torque
• 4. power factor

Question: Slip-rings in a synchronous motor carry____________?

• 1. direct current
• 2. alternating current
• 3. no current
• 4. all of the above

Question: A synchronous motor working at leading power factor can be used as____________?

• 1. voltage booster
• 2. phase advancer
• 3. noise generator
• 4. mechanical synchronizer

Question: The standard full-load power factor ratings for synchronous motors are___________?

• 1. zero or 0.8 leading
• 2. unity or 0.8 lagging
• 3. unity or 0.8 leading
• 4. unity or zero

Question: The rotor copper losses, in a synchronous motor, are met by____________?

• 1. d.c. source
• 2. armature input
• 3. motor input
• 4. supply lines

Question: A synchronous motor will always stop when:______________?

• 1. supply voltage fluctuates
• 2. load in motor varies
• 3. excitation winding gets disconnected
• 4. supply voltage frequency changes

Question: The speed regulation of a synchronous motor is always___________?

• 1. 1%
• 2. 0.5%
• 3. positive
• 4. zero

Question: . In a synchronous motor which loss varies with load ?

• 1. Windage loss
• 2. Bearing friction loss
• 3. Copper loss
• 4. Core loss

Question: For V-curves for a synchronous motor the graph is drawn between:_______________?

• 1. armature current and power factor
• 2. terminal voltage and load factor
• 3. power factor and field current
• 4. field current and armature current

Question: An over-excited synchronous motor takes__________?

• 1. leading current
• 2. lagging current
• 3. both A and B
• 4. none of the above