Posted: 06:16pm 13 Jan 2006

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While playing around with my exercise bike and F&P motor/alternator I have discovered that an old PC power supply is quite happy fed directly from an unmodified F&P turning at various  RPM.  I have tested this particular old power supply at about 80 to nearly 300 volts and it produced regulated voltages 12 and 5 volt right through.  I didnt bother measuring the negative voltage outputs whatever they are supposed to be.

I suppose there is a tweak somewhere in the power supply to up that 12 volts to something adequate to charge batteries.

Posted: 11:11am 16 Jan 2006

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Hi John.

I cant see myself peddling a F&P generator so I can check my email, but this is interresting. The PC powersupply has a pretty dynamic input voltage range, and simply switch off if the input voltage is too low. Watch the high voltage, from memory most powersupplies have two big caps in series rated at something like 330uF 200V, so you have a max input of 400V before things go Bang! ( and it will be a hell of a bang! Seen it happen ).

I've heard you can boost up the 12v output. The powersuppy regulates on the 5v output, so you need to trick it to think the 5v is low so it will up the output level. But thats all I can tell you.

Glenn

Posted: 05:22am 17 Jan 2006

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Hi Glen

Thanks for the high voltage warning,  I doubt I will ever be able to summon up the energy to over stress on high very often!

We are considering building a radio transmitter to go with the pedal generator,  just for historical interest of course.  We are still tossing up between vacuum tube and solid state but you never know we might do something one day.

I will take a look at that 5 volt supply regulation, this is a fairly old power supply so maybe the bits are discrete enough to be recognisable.

John