Power failure alarm

[JohnD]

As I have RCBOs, and three circuits (plus lights) in the kitchen, I did not notice that the espresso machine had splashed hot water over itself, causing the RCBO to trip and the fridge to go off.

Who knows a source of economical devices that will bleep or something when they lose power, to identify a failed circuit?

 

[electronicsuk]

Cheapest I've seen is about £50, which I wouldn't say is economical. It wouldn't take more than a very basic knowledge of electronics to make one for yourself, though. In fact, electrical knowledge alone is enough - just use a relay with a 230v coil, then wire a battery through the NC contacts to a buzzer. Voila!

 

[tim west]

depends on your interpretation of economical:

http://www.ultrasecuredirect.com/acatalog/Mains_Power_Alert-1.html

or build your own with a mains relay, battery and buzzer?

 

[JohnD]

'mmmm, I'm not very good at making things

but ten circuits at £50 each is a bit of a drag

 

[RF Lighting]

It really is dead easy John.

I'm just on my way now, but if you like I could do you a drawing and a parts list tomorrow?

 

[flameport]

Widely used to protect valuable stock in freezers & fridges, computer systems, boats, caravans etc.

So the power goes off, everything in the computer is destroyed and a buzzer comes on to tell you it's now far too late to do anything about it

 

[JohnD]

... I could do you a drawing and a parts list tomorrow?

that would be v helpful, thanks

I suppose I can order the bits from Maplins?

 

[Taylortwocities]

John - easy solution:

Get the burglar alarm that my neighbour has.
The battery is knackered and every time the power goes off the alarm bell goes off for 30 minutes!

 

[ricicle]

I built one recently at work for a sewage station. Alright it cost a lot more than £50, but domestically the principle is the same but on a smaller scale.

Battery, relay, sounder (mine included xenon strobe and battery charger)

Just use the N/C contacts of the 230V relay to energise the alarm from the battery.

 

[flameport]

I suppose I can order the bits from Maplins?

If you haven't used them for a while, you will be astounded at how little they actually have in the way of components. Very expensive too.

 

[JohnD]

I also used Rapid. Any better? Or who?

 

[ricicle]

RS Components

 

[flameport]

Rapid have a reasonable range.

An example of Maplin's uselessness - try finding a 1meg 1watt metal film resistor. For some reason, they don't have any 1W resistors at all.
How about other types of resistor - no, since they don't have any.

 

[bernardgreen]

Or buy a 8W Self Contained Non Maintained Emergency Luminaire and wire it onto the circuit to be monitored via a suitably fused FCU.

such as this one http://www.channelsafety.co.uk/meteor

( there are other makers and sources )

Non maintained means it only switches on from its batteries when the power fails, (( the batteries are charged when there is power and normally a small LED light indicates this is happening ))

This will then light up to say the power has failed to the appliance, and will also light up if there is a total power cut providing emergency lights to find torches, fuse wire, matches and candles.

 

[Aragorn84]

So the power goes off, everything in the computer is destroyed and a buzzer comes on to tell you it's now far too late to do anything about it

Why would a power failure kill everything inside a computer?

I work in IT and yank power leads out of running machines all the time, i've never had one implode yet...

We get the occasional brown out or momentary power cut in our office, which usually is enough to cause the workstations to turn off, although the better machines tend to handle the brown outs a lot better. I've never had a hardware failure due to a powercut though...

I'm sure its possible, but at most you'd take out the power supply. Changed a few of those due to folk switching them to "110v"!