Gallery, Projects and General > Oooops!

Myford M type safety warning (Dewhurst switch)

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SemiSkilled:
 I wonder what that guvn'r did when he got to some traffic lights ?   :)

Pete W.:
Hi there, all,

Eugene, I'm glad you were unscathed.

My ML7 has the Dewhurst switch but it also has a Memdol single phase direct-on-line starter upstream.  The Memdol is the version that incorporates an NVR.

I also have another Memdol in the control box for my Tauco pillar drill.  For some reason, when I made that, I incorporated a reversing switch as well, not a 'Dupar' but one of those ex-gov. two-pole three position toggle switches, the type with the luminous paint tip to the toggle, probably hideously radio-active.   :smart:   

Eugene:
'Aving 'ad a thunk, and taking Andrew and Petes points on board I'm in the process of fitting an in line NVR stop / start with a big emergency stop knob, but retaining the Dewhurst gizmo.

I got one of these from Axminster ... it sits quite nicely alongside the Dewhurst.



Thanks for the input lads,

Eug

rotorhead:
Hi Eug,

You could have saved your pennies on the new switch gear, and just either switched off the socket visible on the wall, or better still pulled the plug out.

No criticism intended, as I've no room to gloat after some of the daft tricks I've done.

Stay safe, switch off at source.

Eugene:
You could have saved your pennies on the new switch gear, and just either switched off the socket visible on the wall, or better still pulled the plug out.

Indeed I could, as I pointed out in my original post. That however still leaves the machine fundamentally unsafe; it's safe working would still rely on any and all users being aware of the potential fault and always operating the correct switch. I may not always be the operator, it could be someone else, who knows? Additionally I might just forget and revert to the habits I've already formed or even get fed up with arsing about with the plug / socket. Better in my view to physically eliminate a hazard than try to avoid it by (fallible) working practice.

At present the NVR on / off,  the emergency button, and wall switch all drop out the relay and stop the machine. However if I ignore the NVR and use the Dewhurst as a stop switch the relay stays in, so it's still potentially hazardous. There must be a way of wiring the Dewhurst stop switch back to the NVR and have it drop the relay but I haven't figured it out yet.

Any ideas Lads?

Eug

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