Question 1 of 37

1. What is the criteria to select the contactor?

Place of use the contactor

Type of supply

Supply voltage and load

Type of load connected

Question 1 of 37

Question 2 of 37

2. Why are control panels provided with control transformer?

To operate the auxiliary circuits

To maintain rated main supply voltage

To supply reduced voltage to power circuit

To maintain rated voltage to load

Question 2 of 37

Question 3 of 37

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

Ensure one earthing in case of other failure

Control the stray field in the panel

Reduce the voltage drop in panel board

Panel board is made in metal box

Question 3 of 37

Question 4 of 37

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

Push button switch

Isolating switch

Toggle switch

Limit switch

Question 4 of 37

Question 5 of 37

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

As per no volt coil rating

As per supply voltage

As per rated current

As per the type of supply

Question 5 of 37

Question 6 of 37

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

Inside area and number of indicating lights in front panel

Suitable method of labelling and cable harnessing

Proper type of protection and measuring system

Outside dimensions and swing area of cabinet door

Question 6 of 37

Question 7 of 37

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

Thermal relay

Electro mechanical relay

Rectifier

Limit switch

Question 7 of 37

Question 8 of 37

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

Sensors

Isolating switch

Push button switch

Indicating lamp

Question 8 of 37

Question 9 of 37

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

Main→Timer→Delta→Star

Star→Main→Timer→Delta

Main→Star→Delta→Timer

Star→Timer→Main→Delta

Question 9 of 37

Question 10 of 37

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

PVC channel

G. channel

DIN Rail

Grommets

Question 10 of 37

Question 11 of 37

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

Silk ties

P.V.C ties

Cotton ties

Nylon ties

Question 11 of 37

Question 12 of 37

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

To increase the current carrying capacity

To increase the insulation resistance

To reduce heat

To reduce the radio interference

Question 12 of 37

Question 13 of 37

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

No volt coil

Stop button

Contactor

Over load relay trip

Question 13 of 37

Question 14 of 37

14. Which switch is operated at OFF load condition?

Two way switch

Limit switch

Push button switch

Isolating switch

Question 14 of 37

Question 15 of 37

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

Controls machine from over loading

Controls machine from over heat

Controls distance movement of any machine

Controls machine from over speed

Question 15 of 37

Question 16 of 37

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

Mounting relays

Pathway for electrical wiring and protection

Mounting double deck terminal contactor

Mounting MCB

Question 16 of 37

Question 17 of 37

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

By operating electromagnet to change the position

By mechanical settings

By using bimetallic strip to change the position

By manual operation

Question 17 of 37

Question 18 of 37

18. 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 18 of 37

Question 19 of 37

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

Contactor

Timer

Relays

Control transformer

Question 19 of 37

Question 20 of 37

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

To maintain constant terminal voltage

To supply the power to the auxiliary circuits

To protect the control elements from over voltage fault

To control the supply voltage to the contactor

Question 20 of 37

Question 21 of 37

21. Which circuit uses limit switches?

Motor control circuits

Lift circuits

Street lighting

Domestic power circuits

Question 21 of 37

Question 22 of 37

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

To minimize the operating cost

To increase the accuracy of operation

To share more loads

To reduce power consumption

Question 22 of 37

Question 23 of 37

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

Single phase AC system

Supply AC system 3 phase

Supply DC 3 wire system

Apparatus AC system 3 phase

Question 23 of 37

Question 24 of 37

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

Due to interlock in reverse contactor

Fault in forward contactor

No volt coil is not energized

No voltage exist in reverse contactor

Question 24 of 37

Question 25 of 37

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

Isolating switch

Time delay relay

Thermal overload relay

Miniature circuit breaker

Question 25 of 37

Question 26 of 37

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

Copper

Bronze

Silver

Brass

Question 26 of 37

Question 27 of 37

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

Lugs and thimbles

Cable binding straps and button

Sleeves

Wire ferrules

Question 27 of 37

Question 28 of 37

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

Protect the motor from over heating and loading

Protect the circuit from earth fault

Switching ON/OFF the circuit

Control the circuit based on time delay

Question 28 of 37

Question 29 of 37

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

For fixing terminal connectors

For fixing contactors

For fixing instruments

For fixing relays

Question 29 of 37

Question 30 of 37

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

Race ways

Grommets

DIN rails

G channel

Question 30 of 37

Question 31 of 37

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

Starting and stopping of shunt motor

Starting and stopping of series motor

Starting and stopping with inching and braking

Resistive loads except motor loads

Question 31 of 37

Question 32 of 37

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

Wire sleeves

Cable binding strap

Nylon cable ties

Wire ferrules

Question 32 of 37

Question 33 of 37

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

Lugs

Grommet

Terminal connector

Thimble

Question 33 of 37

Question 34 of 37

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

Runs in delta only

Starts and stop

Runs normally

Runs in star only

Question 34 of 37

Question 35 of 37

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

Stop button

Auxiliary contact

Main contact

Start button

Question 35 of 37

Question 36 of 37

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

AC ₃

AC₂

AC₄

AC₁

Question 36 of 37

Question 37 of 37

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

Mounting the double deck terminal connectors

Mounting the control accessories without screws

It provides a pathway for electrical wiring

Install the high powered circuit accessories

Question 37 of 37