CET CET Machine Room & Pit Equipment 3

Question 1

What is the purpose of the motor brake on a geared traction elevator?

Accepted Answer

Holds the car stationary when the motor is de-energized

Answer

The motor brake is a spring-set, electrically released device that holds the sheave and car stationary whenever the drive motor is not powered.

Question 2

What is the maximum allowable wire rope (hoist rope) diameter used in most standard traction elevator installations?

Accepted Answer

5/8 inch

Answer

Most standard traction elevator installations use hoist ropes up to 5/8 inch (16 mm) in diameter, though actual size depends on the design load.

Question 3

In a machine room, what is the purpose of the 'selector' or 'dispatching system'?

Accepted Answer

Tracks car position and manages hall and car calls

Answer

The selector is a position-tracking and dispatching system that monitors car location and manages the queue of hall and car calls for efficient service.

Question 4

What is the function of the deflector sheave in a machine room or overhead?

Accepted Answer

Changes the direction of the hoist ropes between the drive sheave and the car or counterweight

Answer

A deflector sheave redirects the hoist ropes to properly align them between the drive sheave and the car or counterweight connection points.

Question 5

What safety device prevents an elevator from operating with the machine room access door open?

Accepted Answer

Machine room door interlock

Answer

A machine room door interlock (access switch) de-energizes or restricts elevator operation whenever the machine room door is opened, protecting personnel.

(CET) Certified Elevator Technician Practice Test

(CET) Certified Elevator Technician Practice Test

CET CET Machine Room & Pit Equipment 3