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Portable Generator Remake Help

  1. Dec 19, 2012 #1
    Hello everyone, I am new to this forum and this is my first post. I have an old generator that I have been working on. It is a rotating-armature 3-phase generator with a commutator. I tore everything off of the shaft because there was a short somewhere and I planned to remake the generator myself for a little learning experience.

    The stator electromagnet seemed fine when I plugged it into a battery, so I left them alone. Then I drilled 12 holes in the shaft. I did this so there would be six "poles" to wrap wire around. I would then use the six poles to make three separate windings.

    Anyways, I got the bolts glued into the holes at the perfect amount of length, they are very close to touching the electromagnet, but they never actually do. Just for a test run, I took a 60ft roll of 16awg wire and wrapped it around two bolts approximately 50-100 turns. I didn't count. I rigged up some slip rings and soldered the connections there, used a multimeter and it fluctuated between 0.01 to 0.14V. This sounds very wrong because the original wire that was wound was 12awg and I would say it had approximately the same amount of turns.

    I found a transformer in the circuit and tested it out. I put a 120VAC connection on it in series with a light bulb(so it wouldn't short circuit) and it returned 0.07V with the leads one way, I then reversed the leads on the voltmeter and it showed 0.01-0.03V.

    Anyways, that's a little background on my story. Here are some minor questions I have now. I would appreciate if you guys could help out.

    Why do I get different voltages when I switch the leads with the voltmeter?
    Wouldn't that much of a jump in voltage greatly decrease the current?
    Whenever I diagnosed it in the beginning, the commutator outputted 1V and it is supposed to be 20V. I know transformers wont work with DC, so how does that jump up?

    Do most generators use a transformer to get to 120VAC or 240VAC? I would think they would just wind the amount of turns needed.
  2. jcsd
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