CEA CEA Motor Controls and Control Circuits Questions and Answers

Question 1

What is the primary purpose of a magnetic motor starter?

Accepted Answer

To provide remote switching and overload protection for a motor

Answer

A magnetic motor starter combines a contactor for remote switching with an overload relay to protect the motor from excessive current.

Question 2

In a three-phase motor control circuit, what is the function of the overload relay heater element?

Accepted Answer

It senses excess current and trips the control circuit to stop the motor

Answer

The overload relay heater element responds to sustained overcurrent by opening the control circuit, de-energizing the contactor and stopping the motor.

Question 3

Which type of motor starter reduces inrush current during startup by applying reduced voltage?

Accepted Answer

Reduced-voltage starter

Answer

Reduced-voltage starters (such as autotransformer, wye-delta, or soft-start types) limit inrush current during motor startup.

Question 4

In a control circuit, what does a normally open (NO) contact do when the coil is energized?

Accepted Answer

It closes to complete the circuit

Answer

A normally open contact closes when the associated coil is energized, allowing current to flow through that part of the control circuit.

Question 5

What is a 'seal-in' or 'holding' contact in a motor control circuit?

Accepted Answer

An auxiliary contact wired in parallel with the start button to maintain the circuit after the button is released

Answer

The seal-in contact is wired in parallel with the start pushbutton so the starter coil stays energized after the momentary start button is released.

(CEA) Certified Electrical Apprentice Practice Test

(CEA) Certified Electrical Apprentice Practice Test

CEA CEA Motor Controls and Control Circuits Questions and Answers