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Single phase ac motor on dc supply?

  1. Sep 24, 2008 #1
    ive got a single phase ac motor that runs on 110V and i'd like to run it on a 12v dc source. basically its a transfer pump for a school bus that runs on vegetable oil, and we currently have to find an outlet to plug the pump into every time we go behind restaurants to fill up our tank. id like to just hook it up to the bus battery but don't know exactly how to do so. we have a 5000 watt inverter which oddly doesn't work, it can't handle the draw from the pump. there are six 12v batteries wired in parallel that the inverter is hooked up to but of course i'd prefer to just wire those batteries somehow directly to the pump. there is more info on the pump here http://transfer.tuthill.com/Products/OilPumps/LTKoilmore.asp and LP50P36Q115 is the model number. any thoughts? thanks!
     
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  3. Sep 24, 2008 #2

    dlgoff

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    I bet the batteries in your inverter are bad. It should be able to handle your load (115v at 12amp).
     
  4. Sep 24, 2008 #3
    you're right, it should. but for some reason it doesn't. the batteries were fully charged, and i even had the bus running the alternator to provide extra power. i think the 5000w rating on the inverter may be a peak output rating and not a constant output. in any case, i'm wondering if there's a way to just hook the batteries directly to the motor. im almost 100 percent sure its a single phase ac motor but i havent taken it apart or anything so i don't know if it may be the type that can take both ac and dc inputs.
     
  5. Sep 24, 2008 #4
    Just an idea, but maybe the huge initial 'kick' that an AC motor requires when it first starts is overloading the inverter.
     
  6. Sep 25, 2008 #5

    dlgoff

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    You're not going to be able to run your AC motor with a DC source. Either get a pump that is powered by a 12v source or get a new inverter. Eventhough your batteries in your existing inverter appear to be good (you say fully charged) you can't really know until you put each one to a load test. I still say your batteries are bad (maybe just one or two leading to a overall decrease in current capability). You should take each one out of the circuit and take it to someone who knows how to load test them, if you don't have a tester yourself.
     
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