All Free Electrical Engineering MCQs with Answers

• A. Three phase A.C. is converted into D.C.
• B. Single phase A.C. is converted into D.C.
• C. Single phase supply is converted into three phase system
• D. None of the above

Explanation: The Kando system takes single-phase AC from the overhead supply and converts it into a three-phase supply for traction motors.

• A. directly through overhead electric line
• B. through individual generator of bogie and batteries
• C. through rails
• D. through locomotive

Explanation: Passenger-coach lighting is normally supplied by an axle-driven generator mounted on the bogie, with batteries providing storage and…

• A. 150 to 175 kg
• B. 100 to 120 kg
• C. 60 to 80 kg
• D. 28 to 30 kg

Explanation: A steam locomotive consumes roughly 28 to 30 kg of coal per kilometre under average operating conditions.

• A. electrical-pneumatic
• B. mechanical-electrical
• C. hydro-mechanical
• D. hydro-pneumatic

Explanation: Suri transmission is a hydro-mechanical transmission, combining hydraulic power transfer with mechanical gearing.

• A. 60 Hz
• B. 50 Hz
• C. 25 Hz
• D. 16 Hz

Explanation: The standard 25 kV railway electrification system uses single-phase AC at 50 Hz, matching the normal power-system frequency used in…

• A. uneven distribution of tractive effect
• B. suitability for passanger as well as freight service
• C. lot of skidding
• D. low co-efficient of adhesion

Explanation: A monomotor bogie uses one traction motor to drive both axles of the bogie, making it suitable for both passenger and freight operation.

• A. 40 Hz
• B. 25 Hz
• C. 16 Hz
• D. non of these

Explanation: Low-frequency railway traction commonly uses 16⅔ Hz or 25 Hz, while 40 Hz is not a standard common frequency for such systems.

• A. has better coefficient of adhesion
• B. are suited both for passanger as well as freight service
• C. has better riding qualities due to the reduction of lateral forces
• D. has all above qualities

Explanation: Monomotor bogies can provide good adhesion, serve both passenger and freight duties, and improve riding by reducing lateral forces.

• A. Retardation and acceleration values
• B. Gradient
• C. Distance between stops
• D. All of the above

Explanation: Specific energy consumption depends on acceleration and retardation, gradients, and the distance between stops.

• A. main line
• B. urban
• C. suburban

Explanation: Main-line trains travel longer distances with fewer stops, so less energy is spent on repeated acceleration and braking per…

• A. Work against the resistance to motion
• B. Work against gravity while moving up the gradient
• C. Acceleration
• D. All of the above

Explanation: Propelling energy must overcome rolling and air resistance, raise the train against gravity on gradients, and accelerate its mass.

• A. easy speed control
• B. high starting tractive effort
• C. equipment capable of with standing large temporary loads
• D. all of the above

Explanation: A good traction system needs controllable speed, high starting tractive effort for overcoming train inertia, and equipment that tolerates…

• A. wheel base of axles is more
• B. degree of curvature is more
• C. both A. and B.
• D. none of the above

Explanation: A longer rigid wheelbase causes greater geometric difficulty on a curve, while a sharper curve increases the difference in wheel travel…

• A. Diesel shunters
• B. Steam locomotives
• C. Electric locomotives
• D. Diesel locomotives

Explanation: Steam locomotives contain large reciprocating masses whose inertia produces substantial unbalanced forces, especially at changing speeds.

• A. main-line service
• B. urban service
• C. sub-urban service
• D. all of the above

Explanation: Main-line trains run between widely spaced stations, so they spend relatively long periods running freely or coasting after acceleration.

• A. neutral wire
• B. rails
• C. cables
• D. common earthing

Explanation: In the usual tramway single-wire system, the overhead conductor supplies current and the running rails carry the return current to the…

• A. Less current drain on the heavy load torque
• B. Current surges after temporary switching off supply
• C. Self relieving property
• D. Commutating property at heavy load

Explanation: After a temporary supply interruption, the series-field flux collapses while the train is still moving; restoration can then produce a…

• A. resistance offered by air
• B. friction at the track
• C. friction at various parts of the rolling stock
• D. all of the above

Explanation: Train resistance includes air resistance, friction and rolling resistance at the wheel-track interface, and friction in bearings and other…

• A. steel mills
• B. power stations
• C. narrow gauge traction
• D. factories for material transportation

Explanation: Battery-operated trucks are mainly used inside factories and warehouses to transport materials over short distances.

• A. Vacuum pump
• B. Ejector
• C. Any of the above
• D. None of the above

Explanation: Both a vacuum pump and an ejector can produce a region of low pressure called a vacuum.