fluid coupling Definition and Purpose A fluid coupling is a hydrodynamic device used to transmit rotating mechanical power. It allows the motor to start under "no-load" conditions and gradually accelerate the massive weight (inertia) of the kiln without tripping electrical breakers or snapping mechanical shafts. 2. Main Components A fluid coupling consists of three primary elements enclosed in a housing: The Pump (Impeller): Connected to the Motor shaft. It acts like a centrifugal pump, hurling