DC DRIVES

1.The DC shunt motor is running with a certain load. The effect of adding an external resistance in field circuit is to

• Increase the Motor Speed
• Stop the Motor speed
• Reduce the motor Speed
• Reduce the armature speed

2. Ward-Leonard controlled Direct current (dc) drives are generally used for

• Light Duty Excavator
• Heavy duty Excavator
• Medium Duty Excavator
• Any of the above

3. When quick speed reversal is is a consideration, the motor preferred is

• Synchronous Motor
• Squirrel cage Induction Motor
• Wound Rotor induction motor
• DC motor

4. Identify the type of speed control method preferred for constant torque drive

• . Field control.
• Armature voltage control.
• Mechanical loading system
• None of above

5. The consideration involved in the selection of the type of electric drive for a particular application depends upon

• Speed control range and its nature
• . Starting Nature
• Environmental condition
• All of the above

6. ------------------- is preferred for automatic drives.

• Squirrel cage induction motor
• Synchronous motors
• Ward-Leonard controlled
• DC. motor

7.An elevator drive is required to operate in

• one quadrant
• two quadrants.
• three quadrants
• four quadrants

8.Speed control by variation of field flux results in

• constant power drive
• constant torque drive.
• variable power drive
• none of the above.

9. The least significant electrical characteristics in selection of electric motor for a flour mill is _

• Efficiency
• Running characteristics
• Braking
• Starting characteristics
• Option 5

10. . The least significant feature while selecting a motor for centrifugal pump is

• Starting characteristics
• Operation speed
• Power rating of motor
• Speed control