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  1. #16
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    Quote Originally Posted by BobL View Post
    Not phases so much but coils themselves maybe connected incorrectly.

    Has the motor ever run correctly to your knowledge?
    Is there evidence that someone has messed about with the wiring inside the motor end cap - can you open the endcap up and take a photo?
    The people I bought the drill from told me it worked, but I they never turned it on.
    The entire stator can be removed from the casting by loosening two grub screws.
    the rotor spins freely withing the stator.
    The resistance readings from the multi meter all came up with 17.4 ohms between the coils.

  2. #17
    BobL is online now Member: Blue and white apron brigade
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    Quote Originally Posted by ml018 View Post
    The people I bought the drill from told me it worked, but I they never turned it on.
    The entire stator can be removed from the casting by loosening two grub screws.
    the rotor spins freely withing the stator.
    The resistance readings from the multi meter all came up with 17.4 ohms between the coils.
    Each coil (1, 2, 3) has two ends (A and B)

    In Y connection all the B's are connected forming the common point - the Phases are then connected to the A's in any order.

    In the ∆ connection 1B is connected to 2A, 2B to 3A, and 3B to 1A.

    If a consistence is not maintained so that an A and B are mixed up on one coil this will cause the problems you describe.

  3. #18
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    Quote Originally Posted by BobL View Post
    Each coil (1, 2, 3) has two ends (A and B)

    In Y connection all the B's are connected forming the common point - the Phases are then connected to the A's in any order.

    In the ∆ connection 1B is connected to 2A, 2B to 3A, and 3B to 1A.

    If a consistence is not maintained so that an A and B are mixed up on one coil this will cause the problems you describe.
    I tried connecting the motor to the inverter: UVW UWV, VUW, VWU, WUV, WVU.
    The motor still refused to turn.
    When I turn up the VFD, it makes this sort of accelerating sound but nothing turns.

  4. #19
    BobL is online now Member: Blue and white apron brigade
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    Quote Originally Posted by ml018 View Post
    I tried connecting the motor to the inverter: UVW UWV, VUW, VWU, WUV, WVU.
    All you are doing there is switching the phases which won't make any difference

    When I turn up the VFD, it makes this sort of accelerating sound but nothing turns.
    Are you starting the VFD at zero Hz? If so then nothing you have said surprises me.

    Because I don't know what sort of VFD you have I can only say that the following is safe with a Powtran.
    It assumes the max frequency is 50Hz and the current max has been set in the VFD to suit the motor
    With a Powtran, with the power off, turn the VFD up to max Frequency.
    Set the acceleration time to 3s and push start/fwd and let the VFD take care of it - if it overloads the VFD will not start and will not damage anything.
    On other VFDs they usually report a error.

  5. #20
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    OK, a couple more questions, what size motor are you trying to drive with the 1.5kw VFD?
    Have you tried to start the motor with the gearbox in the neutral position?
    What make is the machine, can you post a photo of it?

  6. #21
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    Quote Originally Posted by BobL View Post
    All you are doing there is switching the phases which won't make any difference


    Are you starting the VFD at zero Hz? If so then nothing you have said surprises me.

    Because I don't know what sort of VFD you have I can only say that the following is safe with a Powtran.
    It assumes the max frequency is 50Hz and the current max has been set in the VFD to suit the motor
    With a Powtran, with the power off, turn the VFD up to max Frequency.
    Set the acceleration time to 3s and push start/fwd and let the VFD take care of it - if it overloads the VFD will not start and will not damage anything.
    On other VFDs they usually report a error.
    Ok, I turned off the VFD and turned the pot to 60Hz position. I turned it back on and started the motor but it still just makes that buzzing noise and wont turn (it cannot be moved the slightest bit when the VFD is powering the motor (not safe I know).
    How is acceleration generally set on a VFD (how is the option accessed)?
    I know it most likely won't be the same as your VFD, but sometimes Chinese knockoffs are really similar.

  7. #22
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    Quote Originally Posted by Techo1 View Post
    OK, a couple more questions, what size motor are you trying to drive with the 1.5kw VFD?
    Have you tried to start the motor with the gearbox in the neutral position?
    What make is the machine, can you post a photo of it?
    Im19531128ML-Grimston.jpg
    I will take some pictures of the actuall machine tomorrow. I managed to find an advertisement from the 1950's of the machine. I have removed the gearbox completely.

  8. #23
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    melbourne
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    Quote Originally Posted by ml018 View Post
    The motor spins freely even with the gear setup. I have removed all the gears, the motor makes vibrating noises and is hard to turn by hand when the VFD is switched on.
    On one side the motor is easier to turn, then had a sudden jump before stopping again (wrong phases connected?).
    What do you mean here? Do you mean lying the motor on one side then 'turning it over'? What happens if the motor is vertical.

    I'm wondering if the motor is 'poling' - worn bearings letting the rotor touch the stator. With power applied you get attraction, touching and then locking.



    Russ

  9. #24
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    Quote Originally Posted by russ57 View Post
    What do you mean here? Do you mean lying the motor on one side then 'turning it over'? What happens if the motor is vertical.

    I'm wondering if the motor is 'poling' - worn bearings letting the rotor touch the stator. With power applied you get attraction, touching and then locking.



    Russ
    The motor assembly is mounted into the drill casting. It is in a vertical position, when there is no power applied to the motor, it rotates freely with and without the gearbox.
    I will take apart the assembly and take pictures tomorrow.
    I am starting to think that it may be locking due to the rotor and stator touching like you mentioned as I noticed there is a moment when the rotor turns about 60 degrees and halts.

  10. #25
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    Problem solved!
    It was the rotor all along.
    I put the rotor into my lathe and turned down the surface just enough to remove any minute inconsistencies (dings, etc).
    Now the motor fires up as it should.

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