Neodymium magnets are used in electric motors all around us. From the motor that spins a DVD disc to the wheels of a hybrid car, permanent magnets are used in motors everywhere.
While there are many types of electric motors, K&J Magnetics takes a look at one of the simplest types: the Homopolar Motor. What force makes a motor turn? Many articles and books on this subject often begin with a historical perspective, recanting how some of the science behind electric motors was discovered.
We’ll skip that here to keep things brief, but read more about Michael Faraday, Faraday’s Law, the Lorentz force and even Fleming’s left hand rule for motors for more interesting information about the history of electric motors and how they were discovered. The science behind electric motors boils down to this: If you have an electric current flowing through a wire that happens to be in a magnetic field, it feels a force push on it. Specifically, if you have a straight piece of wire sitting in a magnetic field as shown at right, the wire will feel a force pushing on it as shown, at right angles to both the wire and the magnetic field. If you use the left-hand rule to help figure out the direction of the force,
follow these conventions: The direction of the magnetic field is from a north to south The direction of the electric current is that of conventional current, from positive to negative Homopolar Motors:- Homopolar motors were first invented by Faraday, and is perhaps the most simple type of electric motor. It isn’t very useful because it uses very high electrical currents, has poor efficiency and a few other factors. You just can’t get much useful power out of it. One thing it is good for is a great demonstration or subject of a science report.