ELECTRICIAN 2nd YEAR MODULE – AC / DC Motor Drives ONLINE TEST

Question 1 of 33

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

To display the data status of frequency and current

To display the data direction of rotation forward/REV

To change the parameter setting

To store the entered data and factory stored data

Question 1 of 33

Question 2 of 33

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

Variable position control drive

Automatic control drive

Short time duty drive

Intermittent duty drive

Question 2 of 33

Question 3 of 33

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

Photo voltaic cell

Speed sensing

Resistance temperature detector

Opto coupler

Question 3 of 33

Question 4 of 33

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

Torque Vs field current characteristic

Speed Vs armature current characteristic

Speed Vs torque characteristic

Field current Vs armature current characteristic

Question 4 of 33

Question 5 of 33

5. What is IGBT in VF drive?

Rectifier switching device

Field supply switching device

D.C bus switching device

Inverter switching device

Question 5 of 33

Question 6 of 33

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

Basic Operational Panel

Bridge Operator Programme

Bridge Operation Panel

Basic Operation Programme

Question 6 of 33

Question 7 of 33

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

Provides variable voltage to the field winding of motor

Provides a constant voltage to the field winding of motor

Provides a constant voltage to the armature of the motor

Produces required firing current to the firing circuit

Question 7 of 33

Question 8 of 33

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

D.C bus

Inverter

A.C motor

Rectifier

Question 8 of 33

Question 9 of 33

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

Rolling machine

Air Compressor

Heavy duty electric drilling machine

Shearing machine

Question 9 of 33

Question 10 of 33

10. 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 10 of 33

Question 11 of 33

11. What is the function of VSI drives?

Converts A.C to D.C

Converts D.C to D.C

Converts D.C to A.C

Converts A.C to A.C

Question 11 of 33

Question 12 of 33

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

Having lighter gauge winding

No brushes and commutation

Robust in construction

High starting torque

Question 12 of 33

Question 13 of 33

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

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

Stabilize the output voltage from the rectifier

Controls the power delivered to the motor

Smoothening incoming A.C supply

Question 13 of 33

Question 14 of 33

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

Voltage control

Field control

Drives control

Armature control

Question 14 of 33

Question 15 of 33

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

By increasing the field current

By reducing the armature voltage

By increasing the supply voltage

By reducing the field current

Question 15 of 33

Question 16 of 33

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

Protects from mechanical injuries

Easy for connection

Good appearance

Eliminates the electrical interference

Question 16 of 33

Question 17 of 33

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

Group drive

Individual drive

Manual drive

Continuous duty drive

Question 17 of 33

Question 18 of 33

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

Field current

Armature current

Terminal voltage

Back e.m.f

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Question 19 of 33

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

Requires less space

Installation and running cost is less

Power circuit and control circuits are simple

Fast response and wide speed range of control

Question 19 of 33

Question 20 of 33

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

By controlling the armature voltage

By increasing the field current

By reducing the field current

By reducing the armature current

Question 20 of 33

Question 21 of 33

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

Indicate the incorrect operation of BOP

Monitor the parameter of AC drive

Indicate the status of drive

Indicate the display error in reading

Question 21 of 33

Question 22 of 33

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

Hoists

Centrifugal pumps

Elevators

Conveyors

Question 22 of 33

Question 23 of 33

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

Keep the stator flux maximum

Maintain the rated torque at all speeds

Maintain the rotor current minimum

Maintain the speed of motor constant

Question 23 of 33

Question 24 of 33

24. What is electric drive?

A device converts A.C to D.C supply

A machine converts mechanical energy into electrical

An electro mechanical device for controlling motor

A device used as prime mover for generator

Question 24 of 33

Question 25 of 33

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

AC voltage controller

Rectifier controller

Slip controller

DC chopper controller

Question 25 of 33

Question 26 of 33

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

Cyclo converters

Phase sequence indicator

Frequency multiplier

Servo controlled voltage stabilizer

Question 26 of 33

Question 27 of 33

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

Indicate the fault

Display the speed

Display availability of supply

Monitor the parameter

Question 27 of 33

Question 28 of 33

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

Interlocking system in industries

High starting torque

Group drive motors

Control stepless speed in motors

Question 28 of 33

Question 29 of 33

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

Inching operation

Restart the motor

Stop the motor

Reverse the direction of motor

Question 29 of 33

Question 30 of 33

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

COMMS technology box

Field supply unit (FSU)

Speed feedback technology box

Microprocessor based electronic device

Question 30 of 33

Question 31 of 33

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

Easy to operate

Robust in construction

Maintenance free long life

Very high starting torque

Question 31 of 33

Question 32 of 33

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

Press OFF → REV → ON

Press ON → REV → ON

Press ON → REV → OFF → ON

Press ON → OFF → REV → ON

Question 32 of 33

Question 33 of 33

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

It reduce motor current during transient operation

It maintain the torque at low voltage conditions

It detects the overloading condition of motor

It sounds an alarm in no load conditions

Question 33 of 33