Which component is used to connect and disconnect shafts while a system is running?

• A. Clutch
• B. Gear
• C. Belt
• D. Sprocket

Answer: (A)

The key idea is using a device that can connect and disconnect power flow between two rotating shafts without stopping the system. A clutch does exactly that: it temporarily links the driving shaft to the driven shaft or separates them, allowing torque transfer to begin or stop while the machinery is running. This enables smooth starts, gear changes, or maintenance without taking the whole system offline and without shock loads from forcing a direct, locked connection.

Gears, by contrast, are fixed to shafts and mesh to transmit rotation and torque; they don’t provide a built-in way to disconnect while in operation without adding another mechanism. Belts and sprockets transmit motion through contact and tension, but they aren’t intended to be singly responsible for engaging/disengaging power under load—their primary role is to transfer motion, not to selectively connect or disconnect shafts mid-run.