When the load is above _______________ a synchronous motor is found to be more economical?
(A) 2 kW
(B) 20 kW
(C) 50 kW
(D) 100 kW
Light duty cranes are used in which of the following ?
(A) Power houses
(B) Pumping stations
(C) Automobile workshops
(D) All of the above
Which of the following motors are pre-ferred for overhead travelling cranes ?
(A) Slow speed motors
(B) Continuous duty motors
(C) Short time rated motors
(D) None of the above
_______________watt-hours per tonne km is usually the specific energy consumption for suburban services?
(A) 15—20
(B) 50—75
(C) 120—150
(D) 160—200
The rate of acceleration on suburban orurban service is in the range_________________?
(A) 0.2 to 0.5 km phps
(B) 1.6 to 4.0 km phps
(C) 5 to 10 km phps
(D) 15 to 25 km phps
Which of the following methods is used to control speed of 25 kV, 50 Hz single phase traction ?
(A) Reduced current method
(B) Tap changing control of transformer
(C) Series parallel operation of motors
(D) All of the above
The braking retardation is usually in the range__________________?
(A) 0.15 to 0.30 km phps
(B) 0.30 to 0.6 km phps
(C) 0.6 to 2.4 km phps
(D) 3 to 5 km phps
(D) 10 to 15 km phps
The coasting retardation is around_________________?
(A) 0.16 km phps
(B) 1.6 km phps
(C) 16 km phps
(D) 40 km phps
If the co-efficient of adhesion on dry rails is 0.26, which of the following could be the value for wet rails ?
(A) 0.3
(B) 0.26
(C) 0.225
(D) 0.16
The starting torque in case of centrifugal pumps is generally_________________?
(A) less than running torque
(B) same as running torque
(C) slightly more than running torque
(D) double the running torque