Question

question 79 of 100 · multiple choice

if power is lost on a bridge crane, the hoist brakes will______

a lower the hoist slowly

b raise the load slowly

c open

d close

Explanation:

Analyze fail-safe design of crane hoist brakes

Industrial overhead cranes and bridge cranes utilize fail-safe braking systems. These systems are designed to automatically engage and hold the load securely in the event of a power failure.

Determine brake state upon power loss

The brakes are typically spring-applied and electrically released. When electrical power is lost, the electromagnetic coil de-energizes, and mechanical springs force the brake shoes or discs to clamp down. This action is referred to as the brakes "closing" to prevent the load from falling.

Answer:

• (A) lower the hoist slowly
• (B) raise the load slowly
• (C) open
• (D) close (Correct answer)