McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Electrical Engineering .
| 101. |
Light duty cranes are generally used in |
| A. | Power houses |
| B. | . Pumping stations |
| C. | Auto mobile workshops |
| D. | All of the above |
| Answer» D. All of the above | |
| 102. |
The size of an excavator is usually expressed in terms of |
| A. | Crowd motion |
| B. | m 3 |
| C. | Travel in metres |
| D. | Angle of swing |
| Answer» B. m 3 | |
| 103. |
The range of ratings of electric motor used for rolling mills is of the order of |
| A. | 10 to 25 kW |
| B. | 25 to 85 kW |
| C. | 85 to 400 kW |
| D. | 400 to 1000 kW |
| Answer» C. 85 to 400 kW | |
| 104. |
When an electric train is moving down a hill the DC motor operates as a DC |
| A. | Series motor |
| B. | Series generator |
| C. | Shunt motor |
| D. | Shunt generator |
| Answer» B. Series generator | |
| 105. |
Speed controlled by variation of field flux results in |
| A. | Constant power Drive |
| B. | Variable power Drive |
| C. | Constant torture Drive |
| D. | Variable torque Drive |
| Answer» A. Constant power Drive | |
| 106. |
The slip power recovery scheme is used in induction motor for speed control in the range |
| A. | Above synchronous speed |
| B. | Below synchronous speed |
| C. | Both above and below synchronous speed |
| D. | None of the above |
| Answer» C. Both above and below synchronous speed | |
| 107. |
The pair used for frequency converter is |
| A. | Squirrel cage induction motor and synchronous motor |
| B. | Sleep ring induction motor and a synchronous motor |
| C. | Sleep ring induction motor and squirrel cage induction motor |
| D. | All of the above |
| Answer» A. Squirrel cage induction motor and synchronous motor | |
| 108. |
The motor in close are used for collieries, chemical plant is |
| A. | Flame proof type |
| B. | Splash proof type |
| C. | Totally enclosed type |
| D. | Pipe ventilated type |
| Answer» A. Flame proof type | |
| 109. |
The motor enclosure used in wood-working industry is |
| A. | Protected type |
| B. | Totally enclosed fan cooled type |
| C. | Flame proof type |
| D. | Splash proof type |
| Answer» B. Totally enclosed fan cooled type | |
| 110. |
The motor enclosure used for industrial purposes is |
| A. | Protected type |
| B. | Drip proof type |
| C. | Totally enclosed type |
| D. | Open type |
| Answer» A. Protected type | |
| 111. |
Ball-bearings are |
| A. | Used up to 75 kW motors |
| B. | Of long life and low friction loss |
| C. | Costlier and noisy particularly at high speed motor |
| D. | All of the above |
| Answer» D. All of the above | |
| 112. |
Sleeve bearings |
| A. | Are normally of bronze |
| B. | Have self lubricating properties |
| C. | Are used where noise is to be avoided |
| D. | All of the above |
| Answer» D. All of the above | |
| 113. |
Hot bearings of a DC motor may be caused by |
| A. | Poor ventilation |
| B. | Incorrect voltage |
| C. | Loose coupling |
| D. | Lack of or dirty lubricant |
| Answer» D. Lack of or dirty lubricant | |
| 114. |
The least expensive drive is |
| A. | Belt drive |
| B. | Rope drive |
| C. | Chain drive |
| D. | Any of the above |
| Answer» A. Belt drive | |
| 115. |
For very high speed ratio the indispensable drive is |
| A. | Direct drive |
| B. | Rope Drive |
| C. | Chain drive |
| D. | Any of the above |
| Answer» B. Rope Drive | |
| 116. |
15 minute rated motors are suitable for |
| A. | Light duty cranes |
| B. | Medium duty cranes |
| C. | Heavy duty cranes |
| D. | All of the above |
| Answer» A. Light duty cranes | |
| 117. |
For medium duty cranes the short time rating motor used is |
| A. | 10 minutes |
| B. | 15 minutes |
| C. | 30 minutes |
| D. | any of the above |
| Answer» C. 30 minutes | |
| 118. |
The cost of an induction motor will increase as |
| A. | Horse power rating increases but rpm decreases |
| B. | Horse power rating decreases but rpm increases |
| C. | Horse power rating and operating speed increases |
| D. | Horse power rating and operating speed decreases |
| Answer» A. Horse power rating increases but rpm decreases | |
| 119. |
Which of the following motors has series characteristics? |
| A. | Shaded Pole motor |
| B. | Repulsion motor |
| C. | Capacitor start motor |
| D. | None of the above |
| Answer» B. Repulsion motor | |
| 120. |
Which of the following motors is preferred for boom host of a travelling crane? |
| A. | Single phase motor |
| B. | Synchronous motor |
| C. | AC slip ring motor |
| D. | Ward Leonard controlled DC shunt motor |
| Answer» C. AC slip ring motor | |
| 121. |
For crane travel which off the following motors is normally used? |
| A. | Synchronous motor |
| B. | DC differential compound motor |
| C. | Ward Leonard controlled DC shunt motor |
| D. | AC slip ring motor |
| Answer» D. AC slip ring motor | |
| 122. |
Which of the following happens when start Delta starter is used ? |
| A. | Starting voltage is reduced |
| B. | Starting current is reduced |
| C. | None of the above |
| D. | Both A and B |
| Answer» D. Both A and B | |
| 123. |
The characteristics of drive for crane hoisting and lowering are which off the following? |
| A. | Precise control |
| B. | Smooth movement |
| C. | Fast speed control |
| D. | All of the above |
| Answer» D. All of the above | |
| 124. |
In ........the speed can be varied by changing the position of brushes |
| A. | Slip ring motor |
| B. | Schrage motor |
| C. | Induction motor |
| D. | Repulsion motor |
| Answer» B. Schrage motor | |
| 125. |
In which of the following applications variable speed operation is preferred? |
| A. | Exhaust fan |
| B. | Ceiling fan |
| C. | Refrigerator |
| D. | Water pump |
| Answer» B. Ceiling fan | |
| 126. |
The travelling speed of cranes varies from from |
| A. | 20 to 30 m/s |
| B. | 10 to 15 m/s |
| C. | 5 to 10 m/s |
| D. | 1 to 2.5 m/s |
| Answer» D. 1 to 2.5 m/s | |
| 127. |
Which of the following motors is preferred when quick speed reversal is the main consideration? |
| A. | Squirrel cage induction motor |
| B. | Wound rotor induction motor |
| C. | Synchronous motor |
| D. | DC motor |
| Answer» D. DC motor | |
| 128. |
Which off the following motors is preferred when a smooth and resize speed control over a wide range is desired? |
| A. | DC motor |
| B. | Squirrel cage induction motor |
| C. | Wound rotor induction motor |
| D. | Synchronous motor |
| Answer» A. DC motor | |
| 129. |
Which of the following machines has heavy fluctuating of load ? |
| A. | Printing machine |
| B. | Punching machine |
| C. | Planer |
| D. | Lathe |
| Answer» B. Punching machine | |
| 130. |
Which of the following motors is usually preferred for kiln drives? |
| A. | Cascade controlled AC motor |
| B. | Slip ring induction motor |
| C. | Three phase shunt wound commutator motor |
| D. | Any of the above |
| Answer» D. Any of the above | |
| 131. |
In squirrel cage induction motors which of the following methods of starting cannot be used ? |
| A. | Resistance in rotor circuit |
| B. | Resistance in stator circuit |
| C. | Auto transformer starting |
| D. | Start Delta starting |
| Answer» A. Resistance in rotor circuit | |
| 132. |
Electric drive is becoming more and more popular because |
| A. | It is simple, cleaned, compact and reliable |
| B. | It provides easy and smooth control, flexibility in layout, easy starting and facility for remote control |
| C. | It is cheaper in initial as well as in maintenance cost |
| D. | All of the above |
| Answer» D. All of the above | |
| 133. |
The basic elements of an electric drive are |
| A. | Electric motor and the transmission system |
| B. | Electric motor, the transmission and control system |
| C. | The transmission and control system |
| D. | Electric motor and conversion equipment |
| Answer» B. Electric motor, the transmission and control system | |
| 134. |
Introduction of automation in production process has become possible only because of the use of |
| A. | An electric drive |
| B. | Group drives |
| C. | Individual and multi motor drives |
| D. | Individual Drive |
| Answer» C. Individual and multi motor drives | |
| 135. |
DC motor are still preferred for use in |
| A. | Electric excavators, steel mills and cranes |
| B. | Lathes and machine tools |
| C. | Flour Mills and Jaw crushers |
| D. | Paper industry |
| Answer» A. Electric excavators, steel mills and cranes | |
| 136. |
A typical active load is |
| A. | Hoist |
| B. | Lathe |
| C. | Blower |
| D. | Pump |
| Answer» A. Hoist | |
| 137. |
In jaw crushers, a motor has to often start against |
| A. | low load |
| B. | medium load |
| C. | normal load |
| D. | heavy load. |
| Answer» D. heavy load. | |
| 138. |
Motor used for elevators is generally |
| A. | synchronous motor |
| B. | induction motor |
| C. | capacitor start single phase motor |
| D. | any of the above. |
| Answer» B. induction motor | |
| 139. |
In synthetic fibre mills motor with |
| A. | constant speeds are preferred |
| B. | high starting torque are preferred |
| C. | variable speed are preferred |
| D. | low starting torque are preferred. |
| Answer» A. constant speeds are preferred | |
| 140. |
Which of the following motor is preferred for synthetic fibre mills ? |
| A. | series motor |
| B. | reluctance motor |
| C. | shunt motor |
| D. | synchronous motor. |
| Answer» B. reluctance motor | |
| 141. |
Reluctance motor is a |
| A. | self-starting type synchronous motors |
| B. | low torque variable speed motor |
| C. | variable torque motor |
| D. | low noise, slow speed motor. |
| Answer» A. self-starting type synchronous motors | |
| 142. |
A reluctance motor |
| A. | is compact |
| B. | has high cost |
| C. | requires starting gear |
| D. | is provided with slip rings. |
| Answer» A. is compact | |
| 143. |
Power factor in case of reluctance motor is |
| A. | nearly unity |
| B. | always leading |
| C. | 0.8 |
| D. | 0.3 to 0.4. |
| Answer» D. 0.3 to 0.4. | |
| 144. |
The efficiency of reluctance motor is around |
| A. | 95% |
| B. | 90% |
| C. | 75 to 85% |
| D. | 60 to 75%. |
| Answer» D. 60 to 75%. | |
| 145. |
A reluctance motor on over-load runs as |
| A. | synchronous motor |
| B. | induction motor |
| C. | either of the two. |
| D. | all |
| Answer» B. induction motor | |
| 146. |
The size of a excavator is usually expressed in terms of |
| A. | cubic meters |
| B. | travel in meters |
| C. | angle of swing |
| D. | 'crowd' motion |
| Answer» A. cubic meters | |
| 147. |
Ward-Leonard controlled dc drives are generally used for |
| A. | light duty excavators |
| B. | medium duty excavators |
| C. | heavy duty excavators |
| D. | all of the above. |
| Answer» C. heavy duty excavators | |
| 148. |
In case of contactors, the contacts are generally made of |
| A. | copper |
| B. | silver |
| C. | cadmium copper |
| D. | any of the above. |
| Answer» D. any of the above. | |
| 149. |
Which electromagnet is preferred for noiseless operation |
| A. | DC operated |
| B. | AC operated |
| C. | Any of the above. |
| D. | all |
| Answer» A. DC operated | |
| 150. |
For high frequency choppers the device that is preferred is |
| A. | Thyristor |
| B. | TRIAC |
| C. | Transistor |
| D. | GTO. |
| Answer» C. Transistor | |
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