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Mark Harris

Using brushless motor as generator

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Sure it would. I used a generator made out of brushless motor for 3 years on my heli without a problem.

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Would this work?

3phase-bridge.png

I think it would work, but this would be the right configuration in order to make it work.

post-6-1168315289_thumb.jpg

Edited by wilson

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Looking at the coils, it would look like this.

Off course other configuartions will work also, but you have to consider three parameters: Available Power, Speed, and Torque. Once you know any two of these, you can calculate the third by using the following equation: P (watts)=(Torque (in-oz) x Speed (rpm).

post-6-1168315520_thumb.jpg

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If you read the site where those images come from, you'll note that the design shown there is a single phase, you can also tell from the fact that there are only two leads.

However, i am dealing with 3 phase motors, which is pretty much what all of our RC motors are :)

http://www.stanford.edu/~hydrobay/lookat/pmg.html

Anyone know what sort of diodes i'd require (amp wise?)

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It depends on the amps you intend to draw. If your regulator is set to say 2A then 3A fast diodes would be my choice.

Terry

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Mark, I think your circuit would work, however it's not the most efficient rectifier. It looks like what you propose is the equivalent of half-wave rectification on a single phase circuit.

A more efficient method would be to wire the coils into a wye (a.k.a. star) formation and fully rectify the three phases. Here's a website with a circuit diagram to explain it better

http://services.eng.uts.edu.au/~venkat/pe_...s1/ch05s1p1.htm

Cheers,

Simon

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The circuit is basically the same. Diodes are already far enough efficient for the intended use. The linked method would require a control unit triggereing the SCR's at the desired moment. Overkill just to get a DC voltage for powering auxiliary stuff...

I've made a 1kW generator with a big brushless motor and a 6-diode rectifier. With this power, just don't forget the heat sink :)

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I mail order everything :)

Terry

We have the shops which stock everything in the CBD, the only other place to order from is US/UK which is pretty expensive for 6 diodes :)

Thanks for all the advice guys, i wont be re-wiring the motor as i want to keep it as a motor :)

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