Voltage alarm

[frank horton]

Hi all,
The local water authority want a visual (flashing light) and an audible warning when the mains voltage cuts out.....The waste water system is a bio unit and uses a small diaphragm compressor to supply fresh air into the tank...(so the bacteria can consume the poo)....
Now bought this from the bay of fleas....thinking it'd be a simple wiring job....
Well the supplier does not give a wiring diagram....have questioned them but they are a total waste.....
So from the photo can anyone give me a clue as how to wire it in...
I will supply my own lamp....can u suggest a low wattage lamp, guess 9volt led ??????
Incidentally the alarm unit uses a 9volt battery to drive the audio bit...
There are 3 wires, black, red and yellow....
Am guessing that the wires are just the triggers...
Any help would be appreciated....
Ta. Frank

 

[Screwdriver]

Well it does look like it connects to mains voltage with a loose approximation of power, neutral, earth old school colour scheme. I'd pop the lid off to check for a mains transformer and just connect it up via a 3 pin plug, phase and neutral to red and black, ignore the yellow. I would imagine it simply goes off when power is interrupted to the device.

 

[Cyberprog]

All you need is a 240V Relay a 9V Battery and Sounder. 240V Relay is held open when there's power, and closes when the power goes,which closes the circuit on the sounder and battery.