a faster motor

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

Sort of. I made one as a kid although it was from printed instructions. The consisted of an electromagnet wound on a nail. The rotor consisted of a piece of dowel with a nail or screw running down the center line. This was mounted onto a rudimentary bearing. There was a hex nut on the shaft. As the shaft rotated, the nut would drive a spring switch that interrupted current to the electromagnet. The dowel had six radial nails hammered onto it.
This contraption actually ran. It actually had two poles only because it was not possible eleminate one of them.
Bill -- Support the troops. Impeach Bush. Oh, I forgot about Cheney.
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| On 6/27/07 12:52 PM, in article snipped-for-privacy@4ax.com,
| |> Is ther such a thing as a single pole motor? | Sort of. I made one as a kid although it was from printed instructions. The | consisted of an electromagnet wound on a nail. The rotor consisted of a | piece of dowel with a nail or screw running down the center line. This was | mounted onto a rudimentary bearing. There was a hex nut on the shaft. As the | shaft rotated, the nut would drive a spring switch that interrupted current | to the electromagnet. The dowel had six radial nails hammered onto it. | | This contraption actually ran. It actually had two poles only because it was | not possible eleminate one of them.
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.
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| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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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.
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Don Kelly snipped-for-privacy@shawcross.ca
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|> 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 |> |
|> | |> |------------------------------------/-------------------------------------| | | 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.
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| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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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.
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