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Re: Designing safety from the beginning.





> Original Poster: "Doug Brunner" <dabrunner-at-earthlink-dot-net> 
> 
> A deadman switch would be a great idea, if you can get one that can
handle
> the current. 

Doug, all:

Seems to me like the best way to make a deadman switch would be to use a
heavy-duty contactor (relay) in the control cabinet to handle the high
current and then use low voltage/current switches to control it. This way
you could incorporate safety interlocks on access panels and doors too; all
wired in series with the deadman. I'd also put a neon pilot light directly
across the HV primary to show that it was hot. Why neon? Because it isn't
as likely to burn out and give a false indication. (An LED pilot would  be
reliable too, but it just wouldn't 'look right' next to a pig...)

Of course you should never depend on the interlocks and indicators to
protect you 100%.  When you're working on the equipment *always* 'pull the
plug' before poking around inside.

- Mike