Good'ay,
I have a problem that involves 230VAC 50Hz (Australia) lighting.
I wish to set up a relay switch system that will switch on a back-up light in the event that the element in the primary light blows.
The primary light is connected via a motion sensor, together with a photo electric cell to prevent it operating during daylight hours.

The back-up light will need to be connected, after the relay, to the same operating system.

Can you please help me. I believe that I could use a normally closed relay if the current was DC, but I am confused in my mind with the application of AC. I have a licenced person to put it together for me, but he wants me to provide a schematic diagram. Over to you ... ....

 

Welcome to AAC!
How much current does the primary light draw?
Is the light itself operated at 230VAC?

 

Maybe I misunderstand the question but if the light is on a motion sensor and you want to have a back up bulb why not just run two lower power bulbs (in parallel) off the motion sensor? The odds of both burning out at the same time are pretty close to zero. I'm assuming the goal here is to prevent stumbling around in the dark.

Adding a relay is possible but I wonder how reliable that solution would be. It's a simple circuit - sense lack of current through the primary and energize a relay to power the backup. You'd need to power the sensing circuit. Each component adds it's own failure rate.

If you are determined to use a relay system, take a look at the BZ-150. There may be a version for your market. I'd use the primary circuit to generate a hold-off signal. Maybe via a simple current sensor. When the prirmary is burnt out, the hold off goes away and lights the secondary.

And FWIW, an LED light will have a longer life than florescent or incandescent so maybe you solve the problem with better reliability not with a backup solution. You'll never get to 100% so it's really just about increasing reliability.

 

Maybe I misunderstand the question but if the light is on a motion sensor and you want to have a back up bulb why not just run two lower power bulbs (in parallel) off the motion sensor? The odds of both burning out at the same time are pretty close to zero. I'm assuming the goal here is to prevent stumbling around in the dark.

Adding a relay is possible but I wonder how reliable that solution would be. It's a simple circuit - sense lack of current through the primary and energize a relay to power the backup. You'd need to power the sensing circuit. Each component adds it's own failure rate.

If you are determined to use a relay system, take a look at the BZ-150. There may be a version for your market. I'd use the primary circuit to generate a hold-off signal. Maybe via a simple current sensor. When the prirmary is burnt out, the hold off goes away and lights the secondary.

And FWIW, an LED light will have a longer life than florescent or incandescent so maybe you solve the problem with better reliability not with a backup solution. You'll never get to 100% so it's really just about increasing reliability.

Good'ay Philba,
I lost this thread, so will deal with it on the other one to which you have also replied. BUT HERE ARE THE ANSWERS TO THESE QUESTIONS:-
< 1 Amp; and
Yes, 230 volts AC 50Hzs.