a faster motor

| On 6/27/07 12:52 PM, in article snipped-for-privacy@4ax.com, | "out-to-lunch"

|> I would like to find a small inverter (or circuit to build one) which can |> put out a small amount of THREE-phase AC. The idea is that it would be a |> good and safe source of power for small experimental tests of how things |> work that need three phase power to work. It could be used to demonstrate |> small three phase motors. 24 volts or less. Adjustable frequency would |> be cool. |>

|> -- |> |---------------------------------------/----------------------------------| |> | Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |> | |> | first name lower case at ipal.net / snipped-for-privacy@ipal.net |> | |> |------------------------------------/-------------------------------------| | | If you have a 3 phase supply, then arrange 3 good coils in an equilateral | triangle. Put a shaft in the middle and, on this shaft hang an aluminum film | can (if available these days). Failing this, put a beer can on the shaft so | it is free to rotate. Energise the coils. Try it with a paper clip hung so | it can rotate. Reverse one coil and see what happens. Once started see if | it will keep running if one coil is turned so it doesn't contribute to flux | at the center. | Once you have finished with the induction motor, try going synchronous. Use | a very small and light compass needle (the kind I used was one of the little | half inch diameter toy compasses. | I have done this- mind you the coils were originally field coils from a 5HP | shunt DC motor and the AC supply was at 220V, 60Hz. The coils did get hot | but the motors did work.

Or another option would be to build a permanent magnet type three phase syncronous motor/generator and attach a hand crank.

You can put a crank arm with two (can use 1 but two is better balanced) magnets in front of a copper disk which is co-axial and free to rotate. Turn the crank- lo-induction motor. Replace the disc by a second arm of the same radis with magnets and get a synchronous hand cranked motor- provided that you don't try to accelerate or put much load on it. Lots of simple devices work well.