# Lorentz force in motor other than homopolar

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1. Jun 17, 2015

### Aaron380

Hello, I am trying to build a motor. Just a prototype I guess and learning at the moment so just simple stuff but I can't make it work..

I have seen the examples of a homopolar motor and understand the direction of force due to Lorentz force. To be simple I don't want, and don't see the need for a 'switching' motor. One where the current must reverse to change polarities of electromagnets.

In the case of the homopolar motor you find with any google or youtube search there is no coiled wire leading to inefficiency and low power as there isnt much of a force coming from one short travel distance in the magnetic field. Is it possible to place magnets on a disc (I literally have an old CD here with magnets around the edge).

with the poles facing up and down with the disc flat on the ground there should be vertical field lines around the edge of the disc right? I cant seem to find any way to make the disc spin without moving the coil I am trying to spin it with.

There is an effect, but it seems like just a standard electromagnet effect going on. The only coil I have is kind of small but the magnets are just attracted to the 'poles' of the coil. Not pushed perpendicular to them.

Essentially I'm after the simplicity of the homopolar motor but without 'brushes' rubbing and scalable power without burning out one small wire..

Hope I'm making sense, its midnight and I'm giving up for now..

Thankyou

2. Jun 17, 2015

### rumborak

I think you discovered the principal constraint of homopolar motors, and why they're not in great use. Even Wikipedia says:

"This simplicity is achieved at the cost of not being able to have more than one coil turn, which makes this configured homopolar motor unsuited for most useful applications."