What is the purpose of limit switches on cranes?

• A. To measure load weight.
• B. To adjust hoist speed.
• C. To prevent movement beyond safe extents and to protect against over-travel or overload.
• D. To control lighting.

Answer: (C)

Limit switches are safety devices that stop crane motion when a moving part reaches a preset boundary. They prevent movement beyond safe extents of travel and hoist stroke, protecting the structure, equipment, and load from collisions, overstressing components, or unsafe positions. When the trolley or hoist reaches a limit, the switch interrupts power or signals the control system to halt movement, helping ensure operations stay within safe limits and preventing conditions that could lead to overload or damage. They aren’t used to measure load weight, adjust hoist speed, or control lighting, which is why those functions rely on separate sensors and controls.