What is the function of hoist limit switches versus trolley limit switches?

• A. Hoist limit switches stop hoisting at upper or lower limits; trolley limit switches stop trolley travel to prevent collisions or over travel; both prevent crane damage and injuries
• B. Trolley limit switches stop hoisting at upper or lower limits; hoist limit switches stop trolley travel to prevent collisions
• C. Hoist limit switches stop the crane from moving entirely
• D. Both limits are only for gas-powered cranes

Answer: (A)

The main idea is that each type of limit switch controls movement on a different axis to keep the crane and people safe. Hoist limit switches are set to stop vertical movement—the hook and load can’t rise beyond the top limit or descend past the bottom limit. This prevents over-wind or over-lowering the line, protects the rope and hoist components, and avoids loading the hook into the floor or other obstacles.

Trolley limit switches control horizontal movement along the runway. They stop the trolley when it reaches the ends of the runway or would otherwise travel too far, preventing collisions with end stops, derailment, or swinging the load into structures or equipment. By having both kinds of switches, you reduce the risk of equipment damage and injuries.

So the described function—hoist limit switches stopping vertical motion and trolley limit switches stopping horizontal travel to prevent over-travel or collisions, with both contributing to crane safety—is why this choice is best.