Author Topic: Stator Coil math?  (Read 11126 times)

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celticbrooder

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Stator Coil math?
« on: June 15, 2009, 01:39:31 PM »
Have done lots of web searching... maybe I'm just a little thick...


Is there a method/formula for calculating/estimated power generation?

In particular, stator coil spec. - number of turns per coil - (with 16-14ga. wire?)

Would HDD magnets be a resonable alternative?


Situation/goal:

3-phase 12-14.4V - total power output ca. 450W (14.4V 30Amp)

Max. rotor (magnet plate) diameter ca. 100mm

Stator hub min. 28mm - max. outer dia. ca. 130mm

Rotational speed varies between 900 and 7000RPM


Ideally, two sets of stator coils - one set mounted on either side of stator plate: the first 'set' for the basic needs of the engine (ignition, charging, etc. - ca. 150W )

the second for 'accessories' (ca. 300W)


Also, is there any information regarding the shape of the coil core? (i.e. square, round, oval w/angled axis - reletive to impeller shaft - assuming 'air-core' coils)


I assume the math has something to do with the relationship between magnet field strength, turns of coil and rotational speed.


Thanks for any help,


John

« Last Edit: June 15, 2009, 01:39:31 PM by (unknown) »

Flux

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Re: Stator Coil math?
« Reply #1 on: June 15, 2009, 10:00:06 AM »
"I assume the math has something to do with the relationship between magnet field strength, turns of coil and rotational speed."


Yes that's correct. You should find formulae here somewhere. I have my own ways of calculating these things from first principles but others have given formulae that you will probably find easier.


Output power is more difficult. If you know open circuit volts, speed and winding resistance you can calculate the current you will get. It takes more experience to know if the thing will run at that current without frying.


You are aiming at high speed you will have a lot of mechanical issues to overcome but the size falls rapidly with speed for a given power.


Shape of coils doesn't matter much, basically use square coils with square magnets, round coils with round magnets and rectangular coils with rectangular magnets. You can compromise the shape on the inner radius to gain winding space without significant loss so you may find trapezoidal or oval coils used with rectangular magnets.


You can split the stator into 2 parts for different applications. Your big issue if this is variable speed will be regulating the output, these PMAs need electronics to regulate them effectively over a significant speed range, you have lost the absolute simplicity of field control with conventional alternators.


Flux

« Last Edit: June 15, 2009, 10:00:06 AM by Flux »

KilroyOdin

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Re: Stator Coil math?
« Reply #2 on: June 15, 2009, 08:24:17 PM »
http://www.6pie.com/faradayslaw.php


Hi, try the above site. It has all you need.

Best Regards

« Last Edit: June 15, 2009, 08:24:17 PM by KilroyOdin »