Re: [CAD_CAM_EDM_DRO] ELCB Issues

xj5373 wrote:

> Hi,
> I have stripped out the old control system from a Denford Easimill and
> replaced with Mach3 via a Bob Campbell break out board. It works
> beautifully but from the start I had a problem with the machine
> dropping out the ELCB on the mains supply. The machine is plugged into
> a ring main which is fed via an earth leakage circuit breaker from our
> consumer unit (I should say that I am in the UK). I found that if I
> Estopped Mach3, this drops a relay connected to the change pump which
> takes the power off the stepper power supply. Giving it a minute or two
> allowed me to isolate the machine from the mains without the ELCB
> dropping.....more often than not. Isolating immedaitely after Estop
> seemed more likely to drop the ELCB. I have opeated this way since last
> summer but just now I can't reset without losing the ELCB. I have the
> machine powered up but in Estop mode, pressing reset powers the relay
> via the charge pump output of the break out board which switches 240V
> onto the stepper power supply and the inverter which is controling
> spindle speed.
> I know what the ELCB does but what is it that is tripping it? Any help
> or hints greatly appreciated.

The only thing that will trip the ELCB is an earth fault. So there must be
something giving feedback into the protective earth. The first thing I would
be looking at is what is connected to that earth. I don't like the mains
arrangements on any of the American boards I've seen and none of them pass the
European creepage and clearance rules. Which need to be need to be a good 2
times that needed for 110V ;) So I tend to stick to external mains components
such as solid state relays and just run DC from the boards. Then you can
ensure clean live and neutral connections.

--
Lester Caine - G8HFL
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