P
[email protected]
- Jan 1, 1970
- 0
|> 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 / [email protected]
|> |
|> |------------------------------------/-------------------------------------|
|
| 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.
|> 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 / [email protected]
|> |
|> |------------------------------------/-------------------------------------|
|
| 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.