| Although this little homemade device is not actually useful for much, it does demonstrate the concept of energy storage by flywheel. I made it from a brushless DC cooling fan motor. The motor is rated for 12 volts but I have pushed it to 18 without electrical or mechanical failure. At 18 volts the flywheel speeds up to scary high speeds. I have no equipment to measure the speeds, but in theory the video plus audio should be enough to make an accurate estimate. At times, the flywheel appears to be spinning much slower than it actually is, but that is caused by the stroboscopic effect. In reality, it spins too fast to perceive. I tapped into the same coils that accelerate the flywheel and used them for generating power, which is why the voltage is too high to use on LEDs during spin up. Once I disconnect the 12 volt supply, the coils are no longer energized externally and the voltage drops to that which is produce by the spinning flywheel. The magnetic coupling is weak so I can only draw low currents. Industrial units exist in applications where short duration, high output, uninterruptable power is needed or when rapid charge and discharge is needed. They usually suspend the flywheel by magnetic levitation. One example of an ideal application is temporary emergency backup power for hospitals. The hospital's ICE driven generator takes a few seconds to start, and so the flywheel bridges the gap between power loss and the generator's online state. |
