Full definition
Mechanical device enabling on-demand connection and disconnection of power transmission between a motor (driver) and load (driven machine) while one or both are rotating. Industrial types: friction plate (dry or oil-immersed, most common), centrifugal (engage above set RPM, used in small engines and conveyors), pneumatic (inflatable tube, fast response, Eaton Airflex), electromagnetic (electric coil, rapid cycling, Warner Electric), and hydraulic (fluid coupling, smooth engagement). Selection based on torque, inertia, engagement frequency, and heat dissipation. Per DIN 15435. Clutches protect drive trains from overload and allow no-load motor starting. Life measured in engagement cycles: 10^5 to 10^7 depending on type.