NPCH Photocell

[bobsp]

My girlfriend has lights that come on at night, by photocell.

They were not working, so I replaced the cell. There is a group of three switches on the wall, one for the lights in the garden, and one for the garage lights, which when turned on the photocell clicks, and the lights go on, but only stay on for 30-40 seconds, then the cell clicks off, and thats it.

She tells me it used to work fine, and stay on all night and go off in the day. I cant work out why it only comes on, when the light switch on the wall is pressed, for such a short time. The other lights are off, so there is no light coming from them, and even when I cover it with a black bag, it still stays on for 30-40 seconds.

Any ideas?

Oh the third light switch is wired but I have no idea what it is for...

 

[1john]

has anyone replaced that switch or taken it off to try and fix the lights before?

 

[electronicsuk]

Turning the output on for a minute or so is normal behaviour when power is first applied to a photocell, regardless of ambient light levels. If the lights power up during this period, this would suggest that there is power to the cell, but it still simply isn't working properly. If the dusk/dawn levels are fixed, then I can only suggest you double check your wiring at the photocell itself and, failing that, replace it again!

 

[bobsp]

Hi,

No switch not touched before, but I have found out that there maybe possibly a fault/short on one of the spotlights fot the garage, each has a transformer on, so I need to check them.

They do power up for a minute, and then go off, does this sound like a faulty transformer?

Thanks

Bob

 

[electronicsuk]

They do power up for a minute, and then go off, does this sound like a faulty transformer?

That would depend. Is it an electronic transformer? Are all the lights fed from it? Does the same thing happen when you bypass the photocell? The latter it the most obvious way of testing.