Flywheel Energy Calculator
Calculate the rotational kinetic energy stored in a flywheel.
Stored Kinetic Energy
49,348 J
Stored Kinetic Energy vs Flywheel Mass (m)
Formula
## Flywheel Rotational Energy A flywheel stores kinetic energy in its rotating mass. ### Formulas **I = 0.5 m R^2** (moment of inertia for a solid disc) **E = 0.5 I omega^2** (rotational kinetic energy) where m is mass, R is outer radius, and omega = 2 pi N / 60 is angular velocity. The usable energy is the difference between energy at maximum and minimum operating speeds.
Exemplo Resolvido
A 50 kg solid disc flywheel, 200 mm radius, spinning at 3000 RPM.
- 01R = 0.2 m
- 02I = 0.5 x 50 x 0.04 = 1.0 kg-m^2
- 03omega = 2 x pi x 3000 / 60 = 314.16 rad/s
- 04E = 0.5 x 1.0 x 314.16^2 = 49,348 J = 49.3 kJ
Perguntas Frequentes
How much usable energy does a flywheel provide?
Typically only 50-75% of the stored energy is usable because the flywheel must maintain a minimum speed. If speed drops from 3000 to 1500 RPM, only 75% of the energy is extracted (proportional to omega_max^2 - omega_min^2).
What material is best for flywheels?
High-strength steel for conventional designs. For high-speed (>20,000 RPM) energy storage, carbon fibre composites allow higher speeds due to their superior strength-to-weight ratio. Rim stress is proportional to density x radius^2 x omega^2.
What applications use flywheels?
Punch presses, engine crankshafts (smoothing torque pulses), uninterruptible power supplies (UPS), regenerative braking in trains and buses, and grid-scale energy storage systems.
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