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

Thread Starter

Bergonzi237

Joined Mar 12, 2015
9
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?
 

Thread Starter

Bergonzi237

Joined Mar 12, 2015
9
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?
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.
 

R!f@@

Joined Apr 2, 2009
9,734
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
 

Alec_t

Joined Sep 17, 2013
11,665
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.
 

Thread Starter

Bergonzi237

Joined Mar 12, 2015
9
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.
 

Thread Starter

Bergonzi237

Joined Mar 12, 2015
9
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
 

Thread Starter

Bergonzi237

Joined Mar 12, 2015
9
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??
 

Dodgydave

Joined Jun 22, 2012
9,479
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.
 

Thread Starter

Bergonzi237

Joined Mar 12, 2015
9
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!!!
 

KL7AJ

Joined Nov 4, 2008
2,225
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?
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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