Electric motor design

I am trying to build and design an electric motor which essentially would consist of two coils, about 6 x 3 inches long, and about 15mm high.

The idea is that I then want to embedd rae earth magnets in the rotor, at an angle, and hopefully when you put a 240v current ac through the coils the rotor should spin in a particular direction due to the north south / south north effect of the coils

ie, this has to be very basic and i dont want to get too bogged down with control and stuff like that

IS this kind of setup likey to work or any clues where i can discover more about it

the reason I dont want to start trying to induce magnetic fields in the rotor is because of the difficulty of making it, and the weight of it

Any ideas anyone ?

Cheers

Reply to
Ed
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Two ac coils will give a magnet field that flips between north and south rather than a rotating magnetic field. The rotor, even with angular displaced magnets is likely to flip with this field but not necessarily in any controlled direction at start and would almost certainly vibrate if it did rotate.

Tesla in the 1800,s and something tried two ac coils at 90 degrees apart but with the current in each phased by a quarter cycle ..... apparently that worked as it produces a rotating magnetic field. You might like to research that approach.

best of luck

Alan

Reply to
Alan Marshall

I don't think this would work: if it runs at all it would only run smoothly in exact sync with the ac supply (50 magnet pole-pairs per sec, ie 3000rpm with the minimum of 2 magnets); you'd have to manually spin up to close to this speed to start it. The rotor would want to oscillate or bounce-back if it wasn't in sync for any reason - like being under load! If it stopped, it'll probably just sit there humming (both audibly and of burning insulation).

If you want a light-weight rotor you could find out about dc brushless motors. They use magnets round the rotor, and a hall-effect chip which senses these and switches the field coils with transistors. The electronics will get more involved if you want more than a few watts... you might be better off telling us what the application is, and using a separate motor with some sort of drive.

HTH Guy

Reply to
Guy

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