lostforawhile

I had a quick question about the vintage tiger generator on my old Schwinn, I converted my headlight to an LED and fabricated the taillight from scratch, both are 6 volts, negative ground, does anyone know if these old tiger generators are negative or positive ground, and what their output voltage is supposed to be? i'm running my lights on batteries, but it would be nice to have the generator as a backup if needed

ksisler

While I am well aware of the positive ground issues with antique cars, I don't know for sure of any for bike items. I have never heard the question asked regarding bikes... If you hook it up to a Volt Ohm Meter and give the wheel a spin, the meter should register with positive numbers if it is hooked up correctly or no reading or negative numbers if you are hooked up backwards to what the VOM expects. Light bulbs don't care, but most LED based system would so you are right to ask. Does the dyno use two wires or does it use 1 (meaning it grounds through the frame but that doesn't answer your question)?

lostforawhile

it turns out most are 6 volt but are AC, this would mean since I'm using LEDS they would only receive 3 volts, I could use a bridge rectifier but it gets a little complicated since the generator is grounded to the frame.

Looigi

LEDs are better thought of as current rather than voltage devices. AC is usually rated as RMS, which is 0.35 times the peak to peak voltage. The fact that one side of the dynamo is grounded presents no problem with using a bridge rectifier as long as both sides of your lamp circuit are floating wrt ground.

unterhausen

I was going to say the same thing, but the real issue is that both the generator and the light are referenced to the frame. You should be able to use a half wave rectifier, not sure how well it would work