Question 1 of 37

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

AC₁

AC₄

AC ₃

AC₂

Question 1 of 37

Question 2 of 37

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

Control the circuit based on time delay

Protect the motor from over heating and loading

Switching ON/OFF the circuit

Protect the circuit from earth fault

Question 2 of 37

Question 3 of 37

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

Fault in forward contactor

No volt coil is not energized

Due to interlock in reverse contactor

No voltage exist in reverse contactor

Question 3 of 37

Question 4 of 37

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

By manual operation

By using bimetallic strip to change the position

By mechanical settings

By operating electromagnet to change the position

Question 4 of 37

Question 5 of 37

5. Which circuit uses limit switches?

Motor control circuits

Lift circuits

Domestic power circuits

Street lighting

Question 5 of 37

Question 6 of 37

6. 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 6 of 37

Question 7 of 37

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

Star→Main→Timer→Delta

Main→Timer→Delta→Star

Star→Timer→Main→Delta

Main→Star→Delta→Timer

Question 7 of 37

Question 8 of 37

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

Reduce the voltage drop in panel board

Ensure one earthing in case of other failure

Panel board is made in metal box

Control the stray field in the panel

Question 8 of 37

Question 9 of 37

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

For fixing contactors

For fixing instruments

For fixing terminal connectors

For fixing relays

Question 9 of 37

Question 10 of 37

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

Rectifier

Thermal relay

Limit switch

Electro mechanical relay

Question 10 of 37

Question 11 of 37

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

Wire sleeves

Wire ferrules

Cable binding strap

Nylon cable ties

Question 11 of 37

Question 12 of 37

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

As per rated current

As per no volt coil rating

As per the type of supply

As per supply voltage

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

Over load relay trip

Contactor

Question 13 of 37

Question 14 of 37

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

To share more loads

To increase the accuracy of operation

To reduce power consumption

To minimize the operating cost

Question 14 of 37

Question 15 of 37

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

Controls distance movement of any machine

Controls machine from over heat

Controls machine from over loading

Controls machine from over speed

Question 15 of 37

Question 16 of 37

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

G. channel

Grommets

DIN Rail

PVC channel

Question 16 of 37

Question 17 of 37

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

To increase the insulation resistance

To reduce heat

To increase the current carrying capacity

To reduce the radio interference

Question 17 of 37

Question 18 of 37

18. 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

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Question 19 of 37

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

Bronze

Brass

Silver

Copper

Question 19 of 37

Question 20 of 37

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

Thermal overload relay

Miniature circuit breaker

Isolating switch

Time delay relay

Question 20 of 37

Question 21 of 37

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

Lugs

Grommet

Terminal connector

Thimble

Question 21 of 37

Question 22 of 37

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

Supply AC system 3 phase

Apparatus AC system 3 phase

Supply DC 3 wire system

Single phase AC system

Question 22 of 37

Question 23 of 37

23. 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

Resistive loads except motor loads

Starting and stopping with inching and braking

Question 23 of 37

Question 24 of 37

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

Outside dimensions and swing area of cabinet door

Inside area and number of indicating lights in front panel

Suitable method of labelling and cable harnessing

Proper type of protection and measuring system

Question 24 of 37

Question 25 of 37

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

Contactor

Relays

Timer

Control transformer

Question 25 of 37

Question 26 of 37

26. 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 26 of 37

Question 27 of 37

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

Nylon ties

Cotton ties

Silk ties

P.V.C ties

Question 27 of 37

Question 28 of 37

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

Grommets

G channel

Race ways

DIN rails

Question 28 of 37

Question 29 of 37

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

Push button switch

Sensors

Isolating switch

Indicating lamp

Question 29 of 37

Question 30 of 37

30. Why are control panels provided with control transformer?

To maintain rated main supply voltage

To operate the auxiliary circuits

To supply reduced voltage to power circuit

To maintain rated voltage to load

Question 30 of 37

Question 31 of 37

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

Main contact

Stop button

Start button

Auxiliary contact

Question 31 of 37

Question 32 of 37

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

By using Grommets

By using sleeve

By using cable binding straps

By providing nylon cable ties

Question 32 of 37

Question 33 of 37

33. What is the criteria to select the contactor?

Supply voltage and load

Place of use the contactor

Type of supply

Type of load connected

Question 33 of 37

Question 34 of 37

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

Limit switch

Toggle switch

Isolating switch

Push button switch

Question 34 of 37

Question 35 of 37

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

Lugs and thimbles

Wire ferrules

Sleeves

Cable binding straps and button

Question 35 of 37

Question 36 of 37

36. Which switch is operated at OFF load condition?

Push button switch

Isolating switch

Limit switch

Two way switch

Question 36 of 37

Question 37 of 37

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

To supply the power to the auxiliary circuits

To protect the control elements from over voltage fault

To maintain constant terminal voltage

To control the supply voltage to the contactor

Question 37 of 37