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  1. #1
    Join Date
    Jun 2004
    Location
    Grafton, N.S.W.
    Age
    63
    Posts
    185

    Default Electrical problem with a lathe

    G'day All.
    Went to use the lathe yesterday and all it would do is the chuck would rock backwards and forwards.
    It is a 3 phase 3HP pacific.
    I pulled the cover off the electrical area and put the test meter on the 3 wires coming in. I have 240Volts at each of the 3 wires.
    The contacters for forward and reverse have power to all 3 output connectors.
    The strange thing is that the 3 phase coolant pump will not run either.

    Other than getting a sparky in to check it out, anyone have any ideas?

    Thanks.
    Hooroo.
    Regards, Trevor
    Grafton

  2. #2
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,540

    Default

    (With the power disconnected) have you resistance across each of the windings?
    If it was single phase I'd suggest the start coil had burnt out, but with 3 phase??

    Michael

  3. #3
    Join Date
    Jul 2006
    Location
    Athelstone, SA 5076
    Posts
    4,255

    Default

    I assume its standard 3 phase

    measuring to earth can result in back feed thru windings giving the impression that you have all phases...ideally measure across 3 lots of two phases at the bottom of the contactor...ie
    red to blue
    blue to white
    white to red
    each reading should show 415V or there abouts

    make sure the motor has equal resistance across all three windings

  4. #4
    Join Date
    Mar 2009
    Location
    Robertson NSW
    Posts
    133

    Default

    I had a problem similar to that many years ago on my Takisawa (not sure if it was exactly the same problem) but what caused it was at the headstock end of the forward/reverse/stop lever the cams that work the switches had come loose and weren't doing their job properly, just follow the rod along(if you have one) and where it goes into the headstock base remove the cover and have a look-WITH THE POWER OFF, you will be able to work out if the cams are loose.
    Will

  5. #5
    Join Date
    Jun 2004
    Location
    Grafton, N.S.W.
    Age
    63
    Posts
    185

    Default

    The forward reverse rod and cam have 2 limit switches and they are working OK.
    It seems strange that the Coolant pump isn't working either.
    I might wire the power lead directly to the motor and bypass all the contactors and see if she will spin.
    Hooroo.
    Regards, Trevor
    Grafton

  6. #6
    Join Date
    Jun 2008
    Location
    Victoria, Australia
    Age
    74
    Posts
    5,080

    Default

    Sounds like you've lost a phase, and somewhere upstream I'd guess if the coolant pump isn't running either.

    Regards
    Ray

  7. #7
    Join Date
    Jun 2004
    Location
    Grafton, N.S.W.
    Age
    63
    Posts
    185

    Default

    Thanks, Ray.
    A mate is coming to have a look on Friday.
    Hooroo.
    Regards, Trevor
    Grafton

  8. #8
    Join Date
    Apr 2012
    Location
    Healesville
    Posts
    2,129

    Default

    I thing RayG might be on the right track there.

    I sometimes have a machine that will just hum when I switch it on and all I do is push the plug into the socket a bit firmer.

  9. #9
    Join Date
    Jul 2006
    Location
    Athelstone, SA 5076
    Posts
    4,255

    Default

    Quote Originally Posted by RayG View Post
    Sounds like you've lost a phase, and somewhere upstream I'd guess if the coolant pump isn't running either.

    Regards
    Ray
    yep that was what I thought


    I wonder what it was? I wish he would report back...!!!

  10. #10
    Join Date
    Jun 2004
    Location
    Grafton, N.S.W.
    Age
    63
    Posts
    185

    Default

    Mate couldn't make it.
    The sparky that fitted the new main switch to the meterbox is coming back this Friday to fix his FUBAR...
    I'll let you know the outcome.
    Hooroo.
    Regards, Trevor
    Grafton

  11. #11
    Join Date
    Jul 2006
    Location
    Athelstone, SA 5076
    Posts
    4,255

    Default

    Quote Originally Posted by glock40sw View Post
    Mate couldn't make it.
    The sparky that fitted the new main switch to the meterbox is coming back this Friday to fix his FUBAR...
    I'll let you know the outcome.
    appreciated...ta

    glock40sw......being a SW revolver and STI owner I beleive you need to spend some decent money and get a real gun.....

  12. #12
    Join Date
    Jun 2004
    Location
    Grafton, N.S.W.
    Age
    63
    Posts
    185

    Default

    Quote Originally Posted by eskimo View Post
    appreciated...ta

    glock40sw......being a SW revolver and STI owner I beleive you need to spend some decent money and get a real gun.....
    Ha.... The Kimber and SVI race gun more than make up for the Tupperware.
    Hooroo.
    Regards, Trevor
    Grafton

  13. #13
    Join Date
    Jul 2006
    Location
    Athelstone, SA 5076
    Posts
    4,255

    Default

    Quote Originally Posted by glock40sw View Post
    Ha.... The Kimber and SVI race gun more than make up for the Tupperware.
    they do indeed....???well I'm not so sure about the Kimber either..but the SVI does

  14. #14
    Join Date
    Jun 2004
    Location
    Grafton, N.S.W.
    Age
    63
    Posts
    185

    Default

    Well. Mystery solved.
    The sparky rocked up this morning and looked over everything. When he fitted the new 3 phase main switch, he placed 2 active wires for the shed main switch into the same active connector. Thus I only had 2 active phases in the shed. but when you placed a test light across the 3 actives in the shed it showed that they had power. but when the test light was put from active 1 to active 2 there was no light.
    So now the lathe is operational again and turned up a few nylon spacers today.
    Life is good with 3 phase.....
    Hooroo.
    Regards, Trevor
    Grafton

  15. #15
    Join Date
    Oct 2008
    Location
    N.W.Tasmania
    Posts
    1,407

    Default

    Now that should be worth some discount for all the inconvenience he caused, and the lost time etc. I'm glad that's all it was though.
    Rob.

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