Re: brushless motor rectifying

On Fri, 05 Oct 2007 16:59:09 -0500, Mook Johnson wrote:

"Jamie Morken" <jmorken@xxxxxxx> wrote in message
news:O0wNi.818$9m.240@xxxxxxxxxxxx
Mook Johnson wrote:
"Jamie Morken" <jmorken@xxxxxxx> wrote in message
news:CyuNi.125$9m.10@xxxxxxxxxxxx
Hi,

If you have a wye wound brushless generator and rectify it with a 6
diode full wave rectifier, or if you rectify it with a 3 diode half wave
rectifier with the wye common being ground, the voltage of the 6 diode
rectifier will be 1.77x that of the 3 diode rectifier I read, assuming
it is a 1kW generator normally fullwave rectified is it safe to still
extra 1kW of energy using the 3 diode rectifier configuration, or will
the extra current required possibly overload the generator?

Jamie

Probably will not work. Taking 2KW form a 1KW genertor will likely cause
loverload.

Sorry I meant to say:

is it safe to still EXTRACT 1kW of energy using the 3 diode rectifier
configuration


I don't think that can be ansewered without knowing the generator. If you
pulling the same power with at 1/1.77 lower output voltage, the current must
be a factor of 1.77 higher. (by 1.77) Thats ~ 3 times more I2R heating of
the winding in the generator.

If the generator runs cool at 1Kw with the a full wave diode bridge, it
might be worth a shot. If it gets warm - hot to the touch. fagitaboudit.

More like 1.5 times the heating, because it'll be three times more, but at
50% duty cycle in each coil.

You'd want to check to make sure you don't saturate the iron, too.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
.