Re: Control panels safety questions

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Matthew Smith by way of Terry Fritz <twftesla-at-qwest-dot-net>" <matt-at-kbc-dot-net.au>

Hi Jonathan, All

>From experience with motor control systems:  I'd suggest an additional
control - a start button that would *have* to be pressed before the
system could be energised.  You could have, as your main switch, stop
and start buttons operating a contactor which would then feed power to
the rest of the system.  

If your key switch were a dpdt, one of the poles could operate your
continuous mode (when closed) whilst the other could break the circuit
between the start button and the contactor.  So - you could switch main
power on, but once continuous mode were selected, the start button would
remain inoperable.

If you wanted to be *really* safe, you could have a key-lockable start
button as well.

I always favour using a contactor since the system would revert to
'safe' if you had a power outage.

Contact me off-list if you want diagrams.

Cheers

Matthew Smith

Tesla list wrote:
> 
> Original poster: "Jonathan Peakall by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <jpeakall-at-mcn-dot-org>
> 
> Hi All,
> 
> I am constructing the control panel for my new TC, and of course, I have
> some questions:
> 
> I want to have two run modes on the controller. One will be a momentary
> "dead man" style switch, used for demo purposes. The other mode will be a
> continous run mode, so I can do/adjust/whatever while the coil is running,
> or if the coil is to be run for periods longer than one wants to hold the
> momentary switch. I plan to have a key switch for the main power, and a
> second key switch for the continous mode switch. Want I want to do is make
> it so that if the continous mode switch is accidentally left on that the
> main power switch will not operate, to ensure against operator error. What
> would be a good way to achieve this?
> 
> Thanks,
> 
> Jonathan Peakall