brushless motor rectifying

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

Reply to
Jamie Morken
Loading thread data ...

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

Reply to
Mook Johnson

Sorry I meant to say:

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

Reply to
Jamie Morken

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.

Reply to
Mook Johnson

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
Reply to
Tim Wescott

What would saturating the iron do when running as a generator? Its not like a motor that would draw more current I think.

cheers, Jamie

>
Reply to
Jamie Morken

it has twice the current in each phase, but only for half the time, but dissipation rises with square of current, so the heating due to current will be double.

if im not mistaken you should be able to draw x 1.4 the current in the 3 diode config with no extra heating due to current.

but if the windings are over specified - wich would be uneconomical - I cant see any other problems.

but then diodes are a heck of a lot cheaper than replacement generators.

if you want lower voltage can you connect it in delta config ?

Colin =^.^=

Reply to
colin

The windings would no longer support the the BEMF since thieir inductance dropped and the voltage output will drop off until the coreomes out of saturation. Massive distortion of the output waveform as well.

Reply to
Mook Johnson

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.