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How to power a light with a car alternator? Answered

I have made a system where i have a car alternator attached to a stool.  Attached aroung the wheel of the alternator is medical tubing wrapped around a wheel.  This wheel is held up by two pieces of wood.  I have attached handles on either side of the wheel.  On the alternator where the power is dispersed, I have soldered wires to an 1.5 Volt light.  I am spinning the wheel left and right.  But, it will not light the light.  So the questions that I am asking are, which way do I need to spin the alternator wheel if I was looking at the wheel from the front, and how fast I need to spin the wheel.  Any help would be appreciated!!! Thanks!


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Jack A Lopez
Jack A Lopez

Best Answer 10 years ago

Putting some current through the field winding might help.

That is to say with zero current through the field winding you have no magnetic field, and with no magnetic field you won't get any generator action. 

Usually the field winding is powered by the battery, but there may be a trick to getting the thing to "self start" and to drive current through its own field winding, although I don't know *exactly* what this trick is, besides using a battery.

I'll see if I can find you some wiring diagrams to clarify this. So far all I've got is:


10 years ago

.  You need a 12V battery to "excite" the alternator. You may need an external regulator. You should be able to find a wiring diagram on the 'Net.
.  1000-1500 RPM should give you an output. Might need to get to 2500 RPM or higher for full output.
.  Most alternators I've seen spin clockwise when viewed from the pulley end, but running it backwards with little or no load shouldn't do any harm.