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generator light question

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generator light question

Old 02-10-06, 02:41 PM
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generator light question

alright, so i put together a used generator lighting system, but I kept blowing the headlamps. I hooked a voltage meter up and the generator is putting out up to 35 volts! So the question is, where can I get a bulb that won't blow and will still fit in the headlamp? Neither my local bike shop or radio shack had any answers. Any ideas, anyone?
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Old 02-10-06, 03:22 PM
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You might need some kind of voltage regulator. I'm not aware of any lampsets that run on a full 35 volts. Most are 6, some are 12 but I've never heard of 35.
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Old 02-10-06, 11:59 PM
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You may find some theory at Peter White's website and at the Audax U.K. webstier (some references haven't been updated in the last 2 years).

Essentially, your generator always produces the same intensity, 0,5 A. Without a bulb, you'll measure up very high voltages, and some indeed have measured up to 110 or 120 V, because the generator is still trying to produce its 0,5 A. Now I suspect that if you had measured the voltage (at the same speed) with a functionning headlight, you would have measured 10 or 15 V. Quite less, but still way too much!

So the real solution is to put some kind of voltage-limiting device on the lamp. You either design your own, or you buy a controlled headlamp such as the Lumotec which has a zener diode to protect the bulb from over voltage.
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Old 02-11-06, 12:06 AM
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Putting a battery in parallel with the generator will have it regulate voltage pretty nicely...
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Old 02-11-06, 12:21 AM
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Reflectalite sells regulators for this purpose for ~$6.50 plus shipping from UK. They have the best selection of dyno bulbs I've found, too, including screw base halogen bulbs for older Union dynos, hard to find in the US. I've gotten excellent service and shipping isn't really much, this stuff weights next to nothing.

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