smoke alarm to cut out circuit

[a1guvner]

If you had your control circuit going into the (c) of your relay base then take n/c to your n/o contactor on a1 then obviously introduce n to a2 then connect your load through the contactor

 

[chloebear]

where the relay from the smoke alarm connects to activate the contactor

 

[chloebear]

so - live into relay (C) - n/c from relay to (A1) of contactor - neutral on (A2) of contactor

so when the smoke alarm is in normal (not alarming) the relay will hold the contactor closed so that the load will be operating through the contactor & when the smoke alarm activates the relay will operate the contactor & cut off the circuit???????????

 

[a1guvner]

so - live into relay (C) - n/c from relay to (A1) of contactor - neutral on (A2) of contactor

so when the smoke alarm is in normal (not alarming) the relay will hold the contactor closed so that the load will be operating through the contactor & when the smoke alarm activates the relay will operate the contactor & cut off the circuit???????????

You got it,
bear in mind where your control circuit is coming from in relation to the power for the smokes

 

[chloebear]

I was going to take the control power from the same circuit as the smoke detector - it is a different circuit to the one supplying the load, unless that is a problem

 

[a1guvner]

From my limited view so far you should be fine

 

[davesparks]

Have you designed this to stay off until it is reset by a deliberate action, or will it switch on again when the smoke alarm deactivates.
It would be a bit daft if when the smoke clears the contactor drops back in again and the machine starts smoking again!

 

[UKMeterman]

Ok,
To be clear you need to be building a power control panel that is completely seperate from the pump controls. The only link between the two is the power to the pumps / pump controls.

To quote EN 61508 you need to be designing a system that is de-engergise to trip. You need a feed from the alarm system that is live when the alarm is NOT sounding. The normaly open contacts, that are held closed by the feed from the alarm system shall be in series with the main contactor coil. You need separate push button to cause the contactor to pull in when the alarm has been cleared. The relay mentioned above is to be wired as per the stop button or guard interlocks as shown on Safety - Protective Measures and Complementary Equipment

It would be useful if you could also have some status indicators on your unit. A typical DOL motor control box with a box with relay to one side may work in this application.

 

[ruston]

Have you designed this to stay off until it is reset by a deliberate action, or will it switch on again when the smoke alarm deactivates.
It would be a bit daft if when the smoke clears the contactor drops back in again and the machine starts smoking again!

And some form of consumer alarm, they are going to love it if it cuts the pump out on a false alarm and they jump into a freezing pool.

PS. they may not hear alarm from plant room.