Reverse Contactor

[ricicle]

Good-oh.

It's just I kept thinking, Flixborough, Bhopal, Buncefield.....

...Chernobyl


Seriously though it depends on what safety criteria there are by any authoritarian bodies regarding what level of fail-safe there is.
Some systems have early warning and fail-safe on secondary warning or give you a certain amount to time before shut-down. Others may need to cut-out straight away.
Most safety applications require a reset after a fault condition anyhow.

 

[ColJack]

Is it a proper fire alarm with a panel, or a few interlinked smoke sensors?

if it's the former, fire alarm panels usually have volt free contacts to interface with things like smoke extracts and door lock controllers and so on..

 

[Steve]

Wonder if he needs an "everythings ok" alarm

 

[ban-all-sheds]

It's fun to make teaspoons out of Wood's metal...

Just don't try & drink the tea

 

[DamienGiles]

Probably a latching relay - try this as a starting point (dont forget you're 230v, not 12v!)

http://www.enemythunder.com/latchrelay.html[/QUOTE]

That's probably exactly what i'm looking for.

PB1 allows me to re-energise the ciruit after it's either been started up for the first time or been cut.

I can then add 3 relays in series with PB2.

The water and stat can be added onto a normally open relay where the cutting of power from the stat/water sensor.

Since there is no way around sensing the fire alarm, I'll wire the relay up as normally closed where activation makes it open.

If I find an alternative or additional sensor (wood metal sensor) then I can add an additional relay and wire up depending on the output.

These are just a few basic interlinked smoke detectors... I'm using them to detect smouldering above the circuit board and a few other areas.

 

[Spark123]

I think he is joking - in some safety critical applications there are always on healthy tone alarms generated. If this stops then the system is known to be broken.

 

[Lectrician]

So what are you actually making?

 

[ban-all-sheds]

Moonshine?