Question 1 of 33

1. Which device controls the speed of A.C motor in A.C drive?

Field supply unit (FSU)

Microprocessor based electronic device

Speed feedback technology box

COMMS technology box

Question 1 of 33

Question 2 of 33

2. What is the purpose of JOG key in control panel of D.C drive?

Inching operation

Reverse the direction of motor

Restart the motor

Stop the motor

Question 2 of 33

Question 3 of 33

3. What is the function of IGBT in AC drive?

Stabilize the output voltage from the rectifier

Smoothening incoming A.C supply

Converts incoming A.C power into D.C power output

Controls the power delivered to the motor

Question 3 of 33

Question 4 of 33

4. What is electric drive?

An electro mechanical device for controlling motor

A device converts A.C to D.C supply

A machine converts mechanical energy into electrical

A device used as prime mover for generator

Question 4 of 33

Question 5 of 33

5. Which control system is used for Eddy current drives?

DC chopper controller

AC voltage controller

Slip controller

Rectifier controller

Question 5 of 33

Question 6 of 33

6. Which is proportional to the torque in D.C motor?

Back e.m.f

Armature current

Terminal voltage

Field current

Question 6 of 33

Question 7 of 33

7. What is the name of the component marked as 'X' in the block diagram of AC drive?

A.C motor

Inverter

D.C bus

Rectifier

Question 7 of 33

Question 8 of 33

8. Which power modulator is used in the electric drive system?

Phase sequence indicator

Frequency multiplier

Cyclo converters

Servo controlled voltage stabilizer

Question 8 of 33

Question 9 of 33

9. What is the full form of B.O.P in D.C drive?

Bridge Operator Programme

Bridge Operation Panel

Basic Operational Panel

Basic Operation Programme

Question 9 of 33

Question 10 of 33

10. What is the main use of A.C drive?

Interlocking system in industries

Group drive motors

High starting torque

Control stepless speed in motors

Question 10 of 33

Question 11 of 33

11. How can the base speed of D.C shunt motor be increased by using D.C drive?

By reducing the field current

By increasing the supply voltage

By increasing the field current

By reducing the armature voltage

Question 11 of 33

Question 12 of 33

12. What is the function of VSI drives?

Converts A.C to A.C

Converts A.C to D.C

Converts D.C to A.C

Converts D.C to D.C

Question 12 of 33

Question 13 of 33

13. What is the reason for using shielded cable for connecting low level signal circuits in DC drives?

Protects from mechanical injuries

Eliminates the electrical interference

Good appearance

Easy for connection

Question 13 of 33

Question 14 of 33

14. What is the purpose of LCD in Basic Operator Panel (BOP) in AC drive?

Monitor the parameter of AC drive

Indicate the status of drive

Indicate the display error in reading

Indicate the incorrect operation of BOP

Question 14 of 33

Question 15 of 33

15. What is the function of power controller in drive circuits?

It reduce motor current during transient operation

It detects the overloading condition of motor

It maintain the torque at low voltage conditions

It sounds an alarm in no load conditions

Question 15 of 33

Question 16 of 33

16. What is the purpose of PROG/DATA button in BOP of AC drive?

To display the data status of frequency and current

To store the entered data and factory stored data

To change the parameter setting

To display the data direction of rotation forward/REV

Question 16 of 33

Question 17 of 33

17. What is the function of Field Supply Unit (FSU) in DC drive?

Provides a constant voltage to the field winding of motor

Provides a constant voltage to the armature of the motor

Provides variable voltage to the field winding of motor

Produces required firing current to the firing circuit

Question 17 of 33

Question 18 of 33

18. Which type of sensing unit is employed in drive systems?

Photo voltaic cell

Resistance temperature detector

Speed sensing

Opto coupler

Question 18 of 33

Question 19 of 33

19. Why is it necessary to keep V/F ratio constant in a drive?

Maintain the rotor current minimum

Maintain the rated torque at all speeds

Keep the stator flux maximum

Maintain the speed of motor constant

Question 19 of 33

Question 20 of 33

20. Which drive is classified according to mode of operation?

Continuous duty drive

Manual drive

Group drive

Individual drive

Question 20 of 33

Question 21 of 33

21. What is IGBT in VF drive?

D.C bus switching device

Rectifier switching device

Field supply switching device

Inverter switching device

Question 21 of 33

Question 22 of 33

22. Which is the application of single quadrant loads operating in first quadrant in drives?

Hoists

Conveyors

Elevators

Centrifugal pumps

Question 22 of 33

Question 23 of 33

23. Which is the classification of drive according to dynamics and transients?

Automatic control drive

Intermittent duty drive

Short time duty drive

Variable position control drive

Question 23 of 33

Question 24 of 33

24. Which is the correct sequence operation of key button in BOP of AC drive to change the direction of rotation?

Press ON → REV → ON

Press OFF → REV → ON

Press ON → OFF → REV → ON

Press ON → REV → OFF → ON

Question 24 of 33

Question 25 of 33

25. What is the disadvantage of DC drive?

More complex with a single power conversion

More expensive than AC drive for high capacity motor

Installation of DC drives is more complicated

Not suitable for high speed operation

Question 25 of 33

Question 26 of 33

26. What is the advantage of AC drive compared to DC drive?

Requires less space

Installation and running cost is less

Fast response and wide speed range of control

Power circuit and control circuits are simple

Question 26 of 33

Question 27 of 33

27. Why are A.C drives better suited for high speed operation?

High starting torque

No brushes and commutation

Having lighter gauge winding

Robust in construction

Question 27 of 33

Question 28 of 33

28. Why are A.C drives mostly used in process plants?

Maintenance free long life

Robust in construction

Very high starting torque

Easy to operate

Question 28 of 33

Question 29 of 33

29. How can constant torque be obtained from armature and field controlled drives?

By reducing the armature current

By increasing the field current

By controlling the armature voltage

By reducing the field current

Question 29 of 33

Question 30 of 33

30. What is the purpose of LCD on basic operator panel in D.C drive?

Display the speed

Display availability of supply

Monitor the parameter

Indicate the fault

Question 30 of 33

Question 31 of 33

31. Which control system consumes very low power for motion control in AC and DC motors?

Armature control

Field control

Drives control

Voltage control

Question 31 of 33

Question 32 of 33

32. Which type of machine in industries is provided with multi-motor electric drive?

Heavy duty electric drilling machine

Rolling machine

Shearing machine

Air Compressor

Question 32 of 33

Question 33 of 33

33. What is the name of the characteristic curve in D.C drive?

Speed Vs armature current characteristic

Speed Vs torque characteristic

Field current Vs armature current characteristic

Torque Vs field current characteristic

Question 33 of 33