Calculate magnet strength x windings = horse power

[Robert Miller]

Where can I find the figures to calculate a magntic field strength x
windings to
get a figure for horse power. I want to build a 3 hp permanate magnet
electric
motor / generator. The idea is to use perhaps 8 or more large NdFeB magnets
and at least 4 coils per magnet. In a setup similar to a stepper motor. I
can get
the magnets for about $30 or $40 each.
My problem is I don't have a clue how many I will need if I can't calculate
the
power I can get from such a design.
Can anybody help?

Thanks in advance!

Robert Miller

 

[CWatters]

Where can I find the figures to calculate a magntic field strength x
windings to get a figure for horse power. I want to build a 3 hp permanate magnet
electric motor / generator. The idea is to use perhaps 8 or more large NdFeB magnets
and at least 4 coils per magnet. In a setup similar to a stepper motor. I can get
the magnets for about $30 or $40 each. My problem is I don't have a clue how many
I will need if I can't calculate the power I can get from such a design.

Very difficult. For starters I believe the strength of the magnets has no
direct impact on the power of the motor - only on it's efficiency. Of course
you have to achieve a minimum efficiency or your motor will melt. The length
and diameter of the motor controls it's torque. The number of turns effects
the motors speed (RPM/Volt). You need a good book and many hours study - and
so would I.

If you want to experiment there is a small community of model aircraft folk
who are rewinding CDROM motors for use in model aircraft.

http://www.google.com/search?hl=en&q=rewinding+CDROM+motors

or this site has kit for bigger motors...

http://www.handlaunchglider.de/catalog/index.php?cPath=62&osCsid=e036c0fa3ca8fd95f07352ac7a40e096

For parts see the links beginning with "LRK" on the left hand side of the
above page (eg "LRK kpl. Statoren" takes you to a page full of stators)

You could also try asking on the Airplanes-Electric discussion forum here..

http://www.ezonemag.com/

Colin