CET Electrical & Control Systems

Question 1

What is the main function of a relay in elevator control systems?

Accepted Answer

Switch circuits using control signals

Answer

Relays act as electrically operated switches that control circuits using low voltage signals.

Question 2

Which type of motor is commonly used in modern traction elevator systems?

Accepted Answer

AC gearless permanent magnet motor

Answer

AC gearless permanent magnet motors are widely used for their energy efficiency and smooth operation.

Question 3

What is the purpose of a limit switch in elevator systems?

Accepted Answer

Prevent over-travel of the elevator car

Answer

Limit switches prevent the elevator from moving beyond safe boundaries by cutting off power when limits are reached.

Question 4

Which component converts AC to DC for elevator control circuits?

Accepted Answer

Rectifier

Answer

Rectifiers are used to convert alternating current (AC) to direct current (DC) for elevator control components.

Question 5

What safety component cuts off power during an elevator malfunction?

Accepted Answer

Circuit breaker

Answer

A circuit breaker or main disconnect switch is designed to interrupt power during overload or faults to protect the system.

(CET) Certified Elevator Technician Practice Test