Question: The total losses in a well designed D.C. generator of 10 kW will be nearly______________?

• 1. 100 W
• 2. 500 W
• 3. 1000 W
• 4. 1500 W

Question: The condition for maximum efficiency for a D.C. generator is______________?

• 1. eddy current losses = stray losses
• 2. hysteresis losses = eddy current losses
• 3. copper losses = 0
• 4. variable losses = constant losses

Question: D.C. generators are normally designed for maximum efficiency around_____________?

• 1. full-load
• 2. rated r.p.m.
• 3. rated voltage
• 4. all of the above

Question: In a D.C. generator, the iron losses mainly take place in___________.

• 1. yoke
• 2. commutator
• 3. armature conductors
• 4. armature rotor

Question: D.C. generators are installed near the load centres to reduce_____________?

• 1. iron losses
• 2. line losses
• 3. sparking
• 4. corona losses

Question: The purpose of retardation test on D.C. shunt machines is to find out____________?

• 1. stray losses
• 2. eddy current losses
• 3. field copper losses
• 4. windage losses

Question: Which of the following tests will be suitable for testing two similar D.C. series motors of large capacity ?

• 1. Swinburne’s test
• 2. Hopkinson’s test
• 3. Field test
• 4. Brake test

Question: Hopkinson’s test on D.C. machines is conducted at_______________?

• 1. no-load
• 2. part load
• 3. full-load
• 4. overload

Question: For which types of D.C. motor, dynamic braking is generally used ?

• 1. Shunt motors
• 2. Series motors
• 3. Compound motors
• 4. All of the above

Question: Which method of braking is generally used in elevators ?

• 1. Plugging
• 2. Regenerative braking
• 3. Rheostatic braking
• 4. None of the above