TS ECET EEE 2020-7

1. Match the following

Equipment	Bearings
i) High H.P electric machines	a) Foot step or Pivot bearings
ii) Table fans	b) Thrust type ball bearings
iii) Ceiling fans	c) Radial type ball bearings
iv) Turbo generation sets with vertical shaft	d) Thrust or roller bearings

Choose the correct option from the following

A. iv-a, iii-b, ii-c, i-d
B. i-a, ii-b, iii-c, iv-d
C. ii-c, iii-a, i-b, iv-d
D. ii-a, iii-b, iv-c, i-d

Answer : A. iv-a, iii-b, ii-c, i-d
Explanation:-

2. Which of the following is a best exmaple of load equalization

A. Squirrel cage induction motor control
B. Slip ring induction motor control
C. synchronous motor control
D. Ward Leonard ligner control

Answer : D. Ward Leonard ligner control
Explanation:-

3. Under peak load condition the flywheel gives a part of kinetic energy.
The torque required to be supplied by the motor is

A. TM=TL-TFW
B. TL=TM-TFW
C. TM=TFW-TL
D. TFW=TM-TL

Answer : A. TM=TL-TFW
Explanation:-

4. ______ motor is preferred in applications where quick reversal of speed is required

A. Synchronous motor
B. Stepper motor
C. DC Motor
D. Slipring induction motor

Answer : C. DC Motor
Explanation:-

5. A 50HP, 440V, DC shunt motor is braked by plugging. calculate the value of resistance to be placed in series with the armature circuit to limit initial braking current to 150A Ra=1.3 ohm, full load armature current = 100 A and full load speed = 600rpm

A. 5ohm
B. 6ohm
C. 3ohm
D. 8ohm

Answer : A. 5ohm
Explanation:-

6. Which braking is not possible in DC series motor?

A. Regenerative braking
B. Dynamic braking
C. Rheostat braking
D. Reverse current braking

Answer : A. Regenerative braking
Explanation:-

7. The average speed of a train is independent of

A. Distance between stops
B. Acceleration and braking retardation
C. Duration of stops
D. Running time

Answer : C. Duration of stops
Explanation:-

8. Typical speed-time curve of a train running on main line service is shown in figure. In this CD represent

A. Constant accelerating period
B. free running period
C. coasting period
D. Braking period

Answer : C. coasting period
Explanation:-

9. The typical values of the specific energy consumption for main line service is

A. 40-50 W-hr/ton-km
B. 50-60 W-hr/ton-km
C. 20-30 W-hr/ton-km
D. 60-70 W-hr/ton-km

Answer : C. 20-30 W-hr/ton-km
Explanation:-

10. A train has a scheduled speed of 30Kmph on a level track. If the distance between the stations is 1km and stopping time is 20seconds. β=braking retardation=3KmphPs, Vmax=25% greater than average speed. Calculate acceleration required to run the service

A. 8.1 KmphPs
B. 6.4 KmphPs
C. 1.8 KmphPs
D. 2.8 KmphPs

Answer : C. 1.8 KmphPs
Explanation:-