Honda em2500X generator DC winding overheating

Discussion in 'General Electronics Chat' started by hondanut, Oct 10, 2013.

  1. hondanut

    Thread Starter New Member

    Oct 10, 2013
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    So greetings from Minnesota. Generally I can fix just about anything except the generator I just got hosed on. Basically I got the 120v working but the DC winding is glowing red even when the wires are disconnected. So here's what I found. 1) They had the - & + hooked together 2) I think they hooked the diode up wrong. My question is why when I totally disconnected the 12v wires from the DC winding and DC diode is it still heating up?? The only thing I can come up with is that the is still getting a charge from the field winding with no place for the elec. to go. Is that a correct assumption?? Thanks for any and all responses.
     
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
    3,869
    1,393
    If a winding is glowing, then it is shorted. Once the winding gets hot enough to melt the varnish insulation on the wires, it is ruined and may catch fire if you keep running it.

    It's hard to decipher your post, but if you modified the wiring inside the genhead or control panel, you may have made the problem worse.
     
  3. tinkerman

    Member

    Jul 22, 2012
    136
    34
    remove the cover and peek inside. Likely the DC winding is smoked. You probably can dis-assemble the gen head and remove that winding. Hopefully it hasn't damaged the mains. It might have an exciter winding tucked into the sam slots with the DC. Examine the windings very carefully. Power it up after removal of the damaged winding. Might turn out not too bad. Nothing much lost by trying. Probably don't use the DC winding much if ever anyway.
     
  4. #12

    Expert

    Nov 30, 2010
    16,257
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    Yes. The worst that can happen from examining the windings is you end up with a ruined generator, and you already have a ruined generator!
     
  5. hondanut

    Thread Starter New Member

    Oct 10, 2013
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    I just bought it, the guy said it needed a breaker. Well, come to find out someone had their dirty little mitts in it and apparently they didn't know right from wrong. They had the 12v hooked to each other and melted. It appears the diode wasn't wired correctly. The brushes were broke from trying to remove them. So I unhooked all the 12v wires I could find and got the 120v to work. I'm just having a dilemma with the dc winding getting hot and putting off that great smell of burning electrical. I don't understand why that would still be heating up even with the wires disconnected. I have it out and in my hand. Is it heating up because I have it all disconnected and the power needs to go someplace but it can't?
     
  6. Meixner

    Member

    Sep 26, 2011
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    No its heating up because the winding is shorted, you can just leave it out and only use the 120 V output.
     
  7. tinkerman

    Member

    Jul 22, 2012
    136
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    Like Meixner says the DC winding has shorted turns. Don't run the machine like that or you'll damage more windings. Carefully pull out the burned DC winding from the core and then examine the remaining windings for damage (and the papers in ths slots).
     
  8. hondanut

    Thread Starter New Member

    Oct 10, 2013
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    It doesn't test shorted as far as I can tell. I get no continuity where I shouldn't. The schematic I have is poor. I can't tell if the exciter wire goes to the neutral and hot or just the neutral. I do get 000 ohms of resistance between hot and neutral so I was thinking that's shorted but I don't understand this crap without unwinding the winding and if I did that I'd just have another disassembled lesson in my garage.
     
  9. tinkerman

    Member

    Jul 22, 2012
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    Is this the drawing you have?
    http://cdn.powerequipment.honda.com/pe/pdf/manuals/31ZB1615.pdf

    It appears you have a center tapped DC winding. The center tap is the positive lead w/r. The other leads of the winding gr/gr go to two diodes and then to negative terminal. Follow those three leads into the generator windings. See what's doing there. The R and W are the main AC winding.
     
  10. tinkerman

    Member

    Jul 22, 2012
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  11. hondanut

    Thread Starter New Member

    Oct 10, 2013
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    Yes I looked at this diagram too. I have disconnected all them at the winding thinking problem solved. I've run it for very short periods with nothing drawing the power and it's ok, but as soon as I plug in anything presto heat and smoke. I guess I really don't have anymore to lose if I unsolder and unwind the DC. Still doesn't tell me why it's heating up unless it's somehow touching the AC winding. I do need to know two final ??s though. There are two halves that surround the field winding and main winding. Is there suppose to be dialectric grease or heat dissipating grease between them? And Is it possible for the exciter wires to go to the Hot and Neutral.
     
  12. tinkerman

    Member

    Jul 22, 2012
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    The field winding is the part that rotates. It should have two pole faces. The main windings will be heavier wires in two coils on opposite sides of the stator. No grease between them. If you can run it with all wires disconnected at the stator with no heating that's a start. Check for shorts between all the coils. Remove the brush leads and connect 12 volts battery to the brushes with positive to the brush nearest the bearing. Start it up and measure volts from all the coils. You likely won't get full 120 volts from the main winding.
     
  13. hondanut

    Thread Starter New Member

    Oct 10, 2013
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    Thanks. I'll update next week when I reassemble it.
     
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