eddicurrent brakes

Google it. It is quite an old topic and a lot of stuff can be found on it.
I did it and found and here are a few links
<a href="https://www.physlink.com/education/askexperts/ae527.cfm" target="_blank" rel="nofollow noopener noreferrer">What are eddy currents and how do eddy current brakes work?</a>
<a href="https://en.wikipedia.org/wiki/Eddy_current_brake" target="_blank" rel="nofollow noopener noreferrer">Eddy Current Brake</a>