Spinning up a big flywheel with a tiny motor


Active member
I have a project where I want to use a small brushless motor to spin up a large flywheel. It has plenty of power since the flywheel doesn't actually have any load and I can spin it up slowly. However, sensorless motors just can't start anything above a certain inertia, at all. Are there any easy "hacks" to get around that? I know I can just use a bigger wider lower kv motor but once the wheel starts that would just be dead weight.
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How about a loose belt system and a tensioner that you can apply gradually to get the flywheel started? That would let the motor get up to speed before load is applied. Think like the belt and pully system on a lawnmower deck...


Wake up! Time to fly!
Use the clutch and bell from a nitro RC car. that way you can use any kv you want or need. Spin the motor to get the fly wheel going stop motor, clutch releases. Fly wheel goes below wanted rpm spin up motor again clutch reengages to boost rotation of the fly wheel.