Warco Minor Mill/Drill keeps tripping the main fusebox on 'Start'

Discussion in 'General Electronics Chat' started by Bergonzi237, Mar 12, 2015.

  1. Bergonzi237

    Thread Starter New Member

    Mar 12, 2015
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    Hi Folks,
    I'm in UK running on 240V.
    My Mill/Drill annoyingly keeps tripping the fusebox on 'start'. Not every time, but enough to be annoying! I have tried plugging it in to other mains sockets, but have the same result. It is operated by a start/stop NVR switch rated at 18 amps. The motor is an induction motor- 1HP, 240v, 50 hz, 3 amp, 4 pole, 1420RPM, 60 degrees C, with start capacitor of 300MFD and 250VAC.
    I am wondering if the start capacitor is the correct one for the motor? What should it be?
    The power cables have unknown history, and may have had a 'crush' rendered the insulation ineffective, so I will replace those cables. Any other ideas to help please?
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Welcome to AAC!
    Do you mean blowing fuses or tripping circuit-breakers? What rating are the fuses/breakers? Over-current trip or earth-leakage trip?
     
  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Does that size motor needs such high value start cap ?

    And why is this thread in the project forum ?
     
  4. Bergonzi237

    Thread Starter New Member

    Mar 12, 2015
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    Hi Alec. T Thanks for your response. Sorry if my terminology is confusing! When the 'trip' happens, the main feed into the house safety switch trips to 'off', and I have to reset a RCD rated at 63A (next to the red trip switch for that side of the consumer unit). None of the RCB's trip out. I don't know if this is over current or earth trip.

    And I apologise to R!f@@ also if this thread is in the wrong place. For me it is a project to strip down and replace parts and get the thing fixed. Please suggest where it should have gone, and in future if I have to ask for help I'll know where to go.
     
  5. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    I was thinking this was a general chat. Did not realize this was a project for you.

    If you are tripping the RCD, it could be a leak.

    We use ELCB's
     
  6. Bergonzi237

    Thread Starter New Member

    Mar 12, 2015
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    How can I verify/test/identify where the 'leak' might be please?
     
  7. R!f@@

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    You might need Megger tester
     
  8. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    It does indeed sound like an earth leakage fault. If you have a multimeter, an initial test is to unplug your motor then check the resistances between the pins of the plug, while bending the cable. Between the earth pin and both line and neutral there should always be a very high resistance.
     
  9. Bergonzi237

    Thread Starter New Member

    Mar 12, 2015
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    OK, Thank you for this. So, are you both of the opinion that the start capacitor is not the culprit?
    I'm going to replace the mains cable from plug to switch and switch to motor anyway, and try the resistance test. If that all seems fine, I'll connect up the capacitor and give it another few tries.

    Could it be something in the motor itself causing this to happen? The motor has a date on it of 1990.
     
  10. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    Your breaker needs to be a "D type " breaker for motors and welders, take a picture of the breaker in question and post it.
     
  11. Bergonzi237

    Thread Starter New Member

    Mar 12, 2015
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    Hi Dodgydave! OK ,willing try anything. I do have a Colchester Student lathe wired up to it's own 32amp RCB and that has never given me problems, and I use a 130A welder in the garage, which is protected by it's own 16A RCB in the garage consumer box.
    Anyway, here is a pic of the RCD that has been tripping out on my mill. 20150312_141252.jpg
     
  12. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    thats the RCD, i need the breaker that its fed from , if its the RCD thats tripping , then you have an Earth fault.
     
  13. Bergonzi237

    Thread Starter New Member

    Mar 12, 2015
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    OK, thanks. This is the item that trips out, so your diagnosis supports the other replies I've had on this.
    I've just got to wire in the plug on the new power cables I have replaced and I'll be able to fire it up and see it this has cured it. If not then I'm minded to think that I perhaps have a faulty motor that occasionally feels the need to 'earth' itself on start up?!! :) Is that possible??
     
  14. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    Yes if you have an Earth leakage fault on the drill, the only way to stop it tripping is to run it on a NON rcd trip supply, or replace the faulty motor.
     
  15. R!f@@

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    Apr 2, 2009
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    You have a earth leak. Might be a dirty motor
     
  16. gerty

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    Has this machine ever been run on this circuit? If it's new did you hear/see it run before?
     
  17. Bergonzi237

    Thread Starter New Member

    Mar 12, 2015
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    Hi Everyone,
    Result! Replacing the power cable from plug to on/off switch and switch to motor terminal block appears to have cured it. I conducted the 'resistance' test as suggested earlier on the new set up and got no deflection at all. Used the same capacitor as earlier.
    I've pushed the start button 15 times, in various timings, and cannot get it to trip!
    I have returned to being a 'Happy Teddy' :)

    Thank you everyone for your support and suggestions. Good to know there's still some helpful people out there!!!
     
    spark8217, R!f@@ and Dodgydave like this.
  18. R!f@@

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    Apr 2, 2009
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    Good Job :D.

    It seems AAC is the place to hang out for Old timers ;) and Youngsters.
     
    Bergonzi237 likes this.
  19. Bergonzi237

    Thread Starter New Member

    Mar 12, 2015
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    I'm just an old youngster.......getting wiser! :)
     
  20. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    You might want to see if you have the proper time lag breaker installed. These are especially designed for motor start-up conditions.
     
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