Practice Test: Question Set - 08
1. Differentially compound D.C. motors can find applications requiring
- (A) High starting torque
- (B) Low starting torque
- (C) Variable speed
- (D) Frequent on-off cycles
2. In D.C. machines the residual magnetism is of the order of
- (A) 2 to 3 percent
- (B) 10 to 15 percent
- (C) 20 to 25 percent
- (D) 50 to 75 percent
3. Usually wide and sensitive speed control is desired in case of
- (A) Centrifugal pumps
- (B) Elevators
- (C) Steel rolling mills
- (D) Colliery winders
4. Which of the following motors one will choose to drive the rotary compressor?
- (A) D.C. shunt motor
- (B) D.C. series motor
- (C) Universal motor
- (D) Synchronous motor
5. The total losses in a well designed D.C. generator of 10 kW will be nearly
- (A) 100 W
- (B) 500 W
- (C) 1000 W
- (D) 1500 W
6. If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens
- (A) This will make armature to take heavy
current, possibly burning it
- (B) This will result in excessive speed, possibly
destroying armature due to excessive centrifugal stresses
- (C) Nothing will happen to motor
- (D) Motor will come to stop
7. In a D.C. shunt motor, speed is
- (A) Independent of armature current
- (B) Directly proportional to the armature
current
- (C) Proportional to the square of the current
- (D) Inversely proportional to the armature current
8. Which of the following law/rule can he used to determine the direction of rotation of D.C. motor?
- (A) Lenz's law
- (B) Faraday's law
- (C) Coulomb’s law
- (D) Fleming's left-hand rule
9. Which of the following motor is preferred for operation in highly explosive atmosphere?
- (A) Series motor
- (B) Shunt motor
- (C) Air motor
- (D) Battery operated motor
10. The speed of a motor falls from 1100 r.p.m. at no-load to 1050 r.p.m. at rated load. The speed regulation of the motor is
- (A) 2.36%
- (B) 4.76%
- (C) 6.77%
- (D) 8.84%
0 blogger:
Post a Comment