On Wed, Jan 7, 2009 at 7:36 AM, Mike Dawson <[email protected]>wrote:
> Dear All, > > We tried to create a sewing machine based trial to power an XO - we > geared it at about 90:1 so that the two dynamos should spin at about > the same speeed as they would on a bike. > > When connecting the bike light it does light - a little dimmer than > normal - but the digital voltmeter for some reason when just starting > slowly to spin the wheel by hand registers 0.1V or so when it's going > smoothly at full speed it registers absolutely nothing. I tested > measuring a few batteries and it seemed fine. Most "bicycle dynamos' will produce alternating current. The XO requires direct current for charging. A light bulb can operate off either. I suggest you re-test the bike dynamo with the AC setting of your volt meter. If this is the case, you can use a bridge rectifier to change the alternating current into direct current, at the cost of about 1.4 volts. -- Steve Holton [email protected]
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