Question 1 of 37

1. Why are control panels provided with control transformer?

To maintain rated voltage to load

To supply reduced voltage to power circuit

To maintain rated main supply voltage

To operate the auxiliary circuits

Question 1 of 37

Question 2 of 37

2. Why power and control wirings run in separate race ways?

To reduce heat

To reduce the radio interference

To increase the current carrying capacity

To increase the insulation resistance

Question 2 of 37

Question 3 of 37

3. What is the purpose of thermal overload relay in control panel?

Protect the motor from over heating and loading

Switching ON/OFF the circuit

Control the circuit based on time delay

Protect the circuit from earth fault

Question 3 of 37

Question 4 of 37

4. Which device is avoided in the panel board assembly?

Indicating lamp

Isolating switch

Push button switch

Sensors

Question 4 of 37

Question 5 of 37

5. What is the purpose of control transformer used in control panel wiring?

To control the supply voltage to the contactor

To supply the power to the auxiliary circuits

To maintain constant terminal voltage

To protect the control elements from over voltage fault

Question 5 of 37

Question 6 of 37

6. Which cable ties are used to bunch the wires?

P.V.C ties

Nylon ties

Cotton ties

Silk ties

Question 6 of 37

Question 7 of 37

7. How should control circuit voltage and power in a contactor be selected?

As per the type of supply

As per no volt coil rating

As per rated current

As per supply voltage

Question 7 of 37

Question 8 of 37

8. Which device protects from overload and short circuit in a panel board?

Time delay relay

Miniature circuit breaker

Isolating switch

Thermal overload relay

Question 8 of 37

Question 9 of 37

9. What is the name of the device marked as 'X'?

Stop button

Start button

Main contact

Auxiliary contact

Question 9 of 37

Question 10 of 37

10. Which switch is operated at OFF load condition?

Isolating switch

Push button switch

Two way switch

Limit switch

Question 10 of 37

Question 11 of 37

11. What is the function of limit switch in control panel wiring?

Controls machine from over loading

Controls machine from over heat

Controls machine from over speed

Controls distance movement of any machine

Question 11 of 37

Question 12 of 37

12. Which device controls the operations in sequential control systems?

Control transformer

Timer

Contactor

Relays

Question 12 of 37

Question 13 of 37

13. Which circuit uses limit switches?

Motor control circuits

Street lighting

Domestic power circuits

Lift circuits

Question 13 of 37

Question 14 of 37

14. Why the motor is not changing the direction, if reverse push button is pressed in forward and reverse control star delta starter?

No voltage exist in reverse contactor

No volt coil is not energized

Due to interlock in reverse contactor

Fault in forward contactor

Question 14 of 37

Question 15 of 37

15. Which is the correct sequence operation of contactors for operating automatic star-delta starter?

Main→Star→Delta→Timer

Star→Timer→Main→Delta

Main→Timer→Delta→Star

Star→Main→Timer→Delta

Question 15 of 37

Question 16 of 37

16. Which device prevents flare out of stripped and stranded cables in the panel board?

Cable binding straps and button

Sleeves

Lugs and thimbles

Wire ferrules

Question 16 of 37

Question 17 of 37

17. What is the name of the device marked as 'X' in the circuit?

No volt coil

Stop button

Over load relay trip

Contactor

Question 17 of 37

Question 18 of 37

18. Which switch with an actuator is operated by the motion of a machine or part of an object?

Isolating switch

Toggle switch

Push button switch

Limit switch

Question 18 of 37

Question 19 of 37

19. Why is sequential control of motors required in industrial applications?

To increase the accuracy of operation

To minimize the operating cost

To share more loads

To reduce power consumption

Question 19 of 37

Question 20 of 37

20. What is the use of PVC channel in a control panel wiring?

Mounting MCB

Mounting relays

Pathway for electrical wiring and protection

Mounting double deck terminal contactor

Question 20 of 37

Question 21 of 37

21. What essential feature to be considered while designing a layout of control panel?

Outside dimensions and swing area of cabinet door

Suitable method of labelling and cable harnessing

Inside area and number of indicating lights in front panel

Proper type of protection and measuring system

Question 21 of 37

Question 22 of 37

22. What is the use of 'G' channels in control panel?

For fixing terminal connectors

For fixing instruments

For fixing contactors

For fixing relays

Question 22 of 37

Question 23 of 37

23. Which DC load is represented by the DC4 standard duty cycle of contactors?

Resistive loads except motor loads

Starting and stopping of shunt motor

Starting and stopping of series motor

Starting and stopping with inching and braking

Question 23 of 37

Question 24 of 37

24. Which is the standard duty cycle code of the contactor for starting and stopping the AC resistive and inductive load?

AC₄

AC₂

AC₁

AC ₃

Question 24 of 37

Question 25 of 37

25. What is the purpose of DIN-rail used in control panel wiring?

Install the high powered circuit accessories

Mounting the double deck terminal connectors

Mounting the control accessories without screws

It provides a pathway for electrical wiring

Question 25 of 37

Question 26 of 37

26. Which material is used to make open frame bimetallic adjustable thermostat contacts?

Brass

Bronze

Silver

Copper

Question 26 of 37

Question 27 of 37

27. What is the criteria to select the contactor?

Supply voltage and load

Type of supply

Place of use the contactor

Type of load connected

Question 27 of 37

Question 28 of 37

28. What is the name of the accessory used in control panel wiring?

Terminal connector

Thimble

Lugs

Grommet

Question 28 of 37

Question 29 of 37

29. How are the contacts in a contactor engaged for working?

By using bimetallic strip to change the position

By mechanical settings

By operating electromagnet to change the position

By manual operation

Question 29 of 37

Question 30 of 37

30. What is the name of the accessory used in control panel wiring?

Nylon cable ties

Cable binding strap

Wire sleeves

Wire ferrules

Question 30 of 37

Question 31 of 37

31. Which supply is indicated by the color of conductor exhibited on Red, Blue and Black?

Apparatus AC system 3 phase

Supply DC 3 wire system

Supply AC system 3 phase

Single phase AC system

Question 31 of 37

Question 32 of 37

32. What is the name of the wiring accessory used in control panel wiring?

Race ways

DIN rails

Grommets

G channel

Question 32 of 37

Question 33 of 37

33. What is the reason for providing two separate Earthings in panel board?

Control the stray field in the panel

Ensure one earthing in case of other failure

Panel board is made in metal box

Reduce the voltage drop in panel board

Question 33 of 37

Question 34 of 37

34. Which type of device protects motors from over heating and over loading in a panel board?

Limit switch

Thermal relay

Rectifier

Electro mechanical relay

Question 34 of 37

Question 35 of 37

35. What happens if time delay relay of an auto star-delta starter remains in closed condition after starting?

Runs in star only

Starts and stop

Runs normally

Runs in delta only

Question 35 of 37

Question 36 of 37

36. Which accessory is used to mount MCB, OLR in the panel board without using screws?

G. channel

Grommets

PVC channel

DIN Rail

Question 36 of 37

Question 37 of 37

37. How to protect the cable from insects and rats into the panel?

By providing nylon cable ties

By using sleeve

By using cable binding straps

By using Grommets

Question 37 of 37