Q3-Electrical Motor Control

Which of the following devices is not categorized as a control equipment or devices in a starter unit?

• pushbutton switch.

• thermal overload relay.

• selector switch.

• timer relay.

Which of the following procedures is not true about a remote switch?

        

• It provides an automatic ON/OFF cycles of a starter unit.

• It is connected in a main circuit of a starter unit.

• There normally connected in series to each other in a control circuit.

• It is operate due to setting point of temperature, level, flow or pressure.

A no-volt coil protection in the starter unit is used to

• prevent auto restart after loss of supply due to power failure.

• auto restart the starter unit after loss of supply due to power failure.

• prevent manually restart after loss of supply due to power failure.

• auto stop the starter unit after loss of supply due to power failure.

A protection device which break a supply to the control circuit of the starter unit when there is a short circuit fault occur is

• thermal overload relay.

• molded case circuit breaker.

• control fuse or miniature circuit breaker.

• earth leakage circuit breaker.

    A red lamp is used to indicate       

• a motor is in trip condition.

• a motor is in stop condition.

• A motor is in stop and trip condition.

• a motor is in operation condition.

Holding contact is provided by

• limit switch normally close contact (LSc).

• M contactor normally close auxiliary contact.

• M contactor normally open auxiliary contact.

• holding relay auxiliary normally open contact across the start button.

A delta connection is at the point

           

• mark X.

• mark W.

• mark Z.

• mark V.

What is the purpose of the contact mark X?

    

• Break the supply when the timer coil is malfunction

• Break the supply when both coils energize at same time

• Provide an automatic stop due to setting time

• Provide an electrical interlock system.

This starter can be used to open and close the motor operated valve (MOV).

        

• Auto-transformer starter.

• Star-delta starter.

• Forward-reverse DOL.

• Slip-ring starter.

Which of the following statements is not true about an auto-transformer starter?

       

• Starting current value depend on transformer tapping voltage.

• An auto-transformer is connected in parallel with main contactor.

• It can using two or three contactors.

• It is used for a three terminals three-phase motor.