Recessed downlighter problems

redser7

Hi - We have 3 halogen dowlighters in the bathroom and 7 in the kitchen. They are all 12 V 50W bulbs. Each light has its own transformer (10-60W, 11.8V). The make of transformer is CED.

In the past year we've been having sporadic problems with some lights going out and coming back on again. Or if I wriggle a bulb that has gone out or pull or push it just a little it will come back on. This will last for a while and then they will go out again. There appears to be no rhyme or rhythm to it.

So I've been doing a bit research and 2 things came up. Quality of bulbs and transformers. Would you know if CED is a reputable make of transformer? I've also used some Tesco brand bulbs. Are these know to be poor? ie do they heat up too much and knock out the transformers?

Some other things I noticed ... some transformers buzz, is that normal? The bulbs and connectors get really hot, is that normal? The bulb pins are rather sooty, is that normal?

As far as I can see there is plenty of space around the transformers.

I did put loft boards in the attic but I left the lights and transformers exposed. Nothing has changed with the kitchen ceiling lights.

Really appreciate any advice, at this stage it's almost like there is a supernatural force at work!

tomdempsey200

it can be the lampholder contacts giving trouble

the transformers can cycle on/off if they're covered or too close to lamp

redser7

Thanks tom. That did cross my mind first. Why else would they work ok by jiggling the bulbs. But why would they go on/off? Could it be the soot (whatever that is) covering the contacts?

Dfmnoc

Have you taught of going led. might be less hassle to just disconnect the transformer and put in a standard gu10 connection and use a led gu10 bulb

ptogher14

redser7 wrote: »

Thanks tom. That did cross my mind first. Why else would they work ok by jiggling the bulbs. But why would they go on/off? Could it be the soot (whatever that is) covering the contacts?

There's a small filament suspended from two prongs in the lamp. Electricity passing through this causes it to light. Eventually it burns out. When you tap or wiggle the lamp sometimes this filament will reattach itself letting the lamp light again.....but not for long.

It is normal for low voltage 50w lamps to run very hot.
Some transformers will buzz.

I'd recommend getting rid of the transformers and getting GU10 holders and LED lamps. A half decent LED lamp isn't gonna be any dearer than a transformer.

redser7

Thanks folks. So something like this? ...
http://www.lightrabbit.ie/ac240v-bathroom-gu10-fire-rated-downlight-ip65-polished-chrome.html

Dfmnoc

you should get away with just using this http://www.ledbulbs.ie/media/catalog/product/cache/13/image/800x600/cfa0360ac9c8932b555ee31be88d2e38/9/1/9134.jpg
usually only a euro or 2

redser7

Cool, thanks a lot. Hopefully the wires are all long enough

Sounds like a loose connection. I'd check the wiring and consider replacing the bulb holders if there's nothing obvious.
Transformer buzz is normal it's called magnetostriction and it's to do with a 50hz vibration caused by the electromagnetism of the AC wave going through coils, rattling the transformer laminations. The cheaper transformers and single insulated ones more frequently do this.

LED's are more likely to cause buzz than a resistive incandescent like the tungsten/halogen you are using.
I've yet to see an LED with a colour temperature as good as the tungstens.

Transformers do go bad every now and again. If the same bulb and transformer is giving bother after you've established it's not wiring/connection I'd replace the transformer.

redser7

Thanks Liam. Popped to an electrical wholesalers at lunch time. Guy there sold me a couple of lampholders to try. He said that over time or if you haven't pushed the bulbs in 100% you can get arcing and oxidation of the contacts. That would explain the soot. So the contact made is bad. Fingers crossed it is this simple!
But after talking to him and the post above I think I'll take out the transformers and go for GU10 leds.

Danny Mulcahy

Some GU10 lamp holders and poor quality LED bulbs can cause similar issues to what you have now so dont go for the cheapest option.

I do agree replacing your lights to GU10 and LED lamps is the way to go though

redser7

Thanks a lot Danny

redser7

redser7 wrote: »

I think I'll take out the transformers and go for GU10 leds.

LEDs on a GU10 fitting still have a transformer, it's just built in and usually goes before the LED does.

redser7

Thanks Liam