Flywheel

A heavy-mass wheel mounted on a rotating shaft that stores kinetic energy (E = ½Iω², where I is moment of inertia and ω is angular velocity) to smooth out speed fluctuations caused by intermittent or pulsating loads. By releasing stored energy during peak demand and absorbing excess during light load, the flywheel reduces speed variation (coefficient of fluctuation) to acceptable levels — typically 1-5% for industrial machinery. Applications: mechanical presses (store energy between strokes, releasing it during the brief forming period), reciprocating compressors and pumps (smooth pulsating torque), internal combustion engines (maintain rotation between power strokes), and energy recovery systems. Materials: cast iron GG25 (standard), ductile iron (impact resistance), welded steel (large sizes), or advanced composites (high-speed energy storage). Per ASME standards for press flywheels. Rim speed limited to 25-30 m/s for cast iron, higher for steel. Often combined with a clutch (clutch-brake unit) in press applications.