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  1. I'd highly doubt the coil wiring will have any sort of identification. They're usually just the enammeled copper wiring with a bit extra insulation slid over the top.

  2. #22
    I think I have it sorted now! the motor was wired in star and has 6 coils which are interconnected in pairs. Before I cut the star connection I tested the input wires and got 100 ohms across each phase, which in star con fig is 2 coils (4 actually). When I cut the star connection and retested each coil I got continuity from the buzzer and 50 ohms reading.

    The question is can I run it using a capacitor in delta configuration to test? or will it only run from the inverter and risk damaging that if I got the rewire wrong? Lastly can I use a cap from another 240v motor or is the capacitance value dependant on the motor?

    Thanks again

  3. #23
    Thing is you will need a few caps and they will be different sizes for the phases. By the time you have messed around you might as well get an inverter (vfd). If the motor does not work out i would still use another 3 phase motor.
    If the nagging gets really bad......Get a bigger shed:naughty:

  4. #24
    Ah. I thought is was 1 cap in one of the phases or is that for star config?

    I was only wanting to try the cap route for initial testing after I rewired the motor as I don't want to damage the VFD. (already got one)

    Is there any other way to test a 3 phase motor?

  5. Quote Originally Posted by Ross77 View Post
    Ah. I thought is was 1 cap in one of the phases or is that for star config?

    I was only wanting to try the cap route for initial testing after I rewired the motor as I don't want to damage the VFD. (already got one)

    Is there any other way to test a 3 phase motor?
    you wont damage the VFD*. if its a half decent one it'll have foldback current limiting and overheat protection.

    *but dont blame me if you let out magic smoke
    Last edited by irving2008; 05-04-2013 at 07:34 PM. Reason: spelin'

  6. #26
    *but dont blame me if you let out magic smoke
    Ah that old chestnut "It'll be allright but don't blame me if it goes wrong....."

    I'll have to dig out the VFD and see if its 'spanner rewiring motor proof' Got to find the dam thing first, bought it a few years ago for the lathe and never managed to get a 3 phase motor for it.

    Looks like a job for tomorrow night after I have finished the tilling

  7. You only effectively need 1 capacitor to run a three phase motor from a single phase, however you normally need to use a few connected in parallel to acheive the required capacitance.

    Search for 'static phase convertor' if you want to know more, however you need to check the generated voltages while running to ensure the 'false' phases aren't too high/low, and the voltages will also vary depending on load.

  8. #28
    Ross, as m_c said ,you do usually only need one capacitor, connected across one leg of the delta triangle, but to get the correct capacitance you may need a couple in parallel. It is sometimes necessary to have an additional capacitor to increase the capacitance for initial starting, especially if starting under some load. this extra capacitor can be operated with a spring loaded switch, held on until the motor reaches speed (only a second or so) or as I do now using a timer circuit. G.

  9. #29
    If you really want to go down that route then have a read of this. It helped me get my cross feed motor going on my BP. I could not swap that out because of the frame of the motor.

    phaseconverter
    If the nagging gets really bad......Get a bigger shed:naughty:

  10. #30
    Exactly! G.

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