What are the types of brakes for lifting structures and what are their functions?

What are the types of brakes for hoisting structures and what are their functions?

A. Safety brake, mounted on the drum, used to hold the brake when the crane stops working

B. Safety brake, mounted on the high-speed shaft of the motor and reducer, used to hold the brake when the hoisting mechanism stops working

C. Working brake, mounted on the drum, used to hold the brake when the crane stops working

D. Mounted on the high-speed shaft of the motor and reducer, used for braking when the hoisting mechanism stops working

Correct Answer: AD