Halogen transformers keep burning out - HELP!

[MarkyQ]

Hi all,

I moved in to a flat about a year ago. There are 12 halogen spotlights in the ceiling of one room, on 2 seperate circuits.

Initially, both circuits had dimmer switches.

Within a few weeks, the first lamp went out, others soon followed - on both circuits.
The problem was not with the lamps, but the transformers. One of the transformers had actually melted and burnt a little when i removed it!

As this has happened, i replaced the transformers with, i assume better quality ones which seem to last longer and, although all the transformers have said they were dimable, i've changed the dimmer switches for standard on/off switches which also seems to give all the transformers longer life.

All of the old transformers which i have removed and, of course, all of the new transformers i have installed have not been in direct contact with insulation and have had a good pocket of clear space around them.

Nevertheless, the transformers - even two of the new ones - have still cut out and died within 6 months of their installation and now, presumably due to the hotter weather, three of the original ones have died in a week!

Meaning that now, 2 of the original transformers remain. The other 10 originals, and two of their replacements have all burnt out... Surely, something's wrong with that, right?!

The flat is poorly ventilated and does stay warm, even in winter, but i'm sure there must be some kind of transformer i can install that:
a) won't get dangerously hot, and
b) will last longer... I mean, surely, over a year's life span is not an unreasonable expectation?

Can anybody:

1) Recommend a decent transformer? (i don't mind paying a higher price, i just don't want to have to change them all the time. Aside from the hassle, every time i take a light fitting out, it takes chips out of the plasterboard ceiling. =-/)

2) Give me any tips? - Is there something i should have done which i haven't?

3) Comment on 'auto-reset' transformers? - i gather these turn off (rather than burn out) when they get hot, then restart when they cool down, meaning they wouldn't need to be replaced... Are they any good?

Apologies for the long post, and thanks if you've bothered reading this far!
Any help would be much appreciated.
Thanks in advance, people!

 

[Iggifer]

A much cheaper, long term solution is to simply replace them with 230V fittings. If you measure the diameter of the cutout you should be able to find reasonably priced replacements for your current fittings.

This means you will only need to replace the lamps as they fail.

If you want to not replace lamps, think about putting LED's in.

12v halogen lamps are a slightly better light than 230v but not considerably that I would bother with replacing transformers to keep the benefit.

You're going to be paying upwards of £60 to replace just the failed trannys, and more like £150 to replace them all. For that you can replace all the fittings with these:

http://www.screwfix.com/p/jcc-fireguard-fixed-fire-rated-recessed-downlight-white-240v/52944

You can, just change the lampholder from a GU5.3 base to a GU10 base, but dependant on your lampholders, I have no idea how straightforward this is, but then you could do the whole lot for about £20

 

[ban-all-sheds]

Plan B - get rid of the lights altogether, and install something actually designed to light up rooms.

 

[bernardgreen]

The "transformers" you have are electronic switch mode power supplies, Many of these supplied for lighting are a compromise between cost and build quality.

A real transformer, two coils of wire on a magnetic core will be far more reliable as there are no electronic components to fail..

One of many suppliers is

http://www.slvlightingdirect.com/slv-451060-standard-toroidal-transformer-12v-60va.html

 

[pjcomp]

If replacing with 230V lamps you can probably keep the fittings, just ditch the transformers and replace the lampholders with GU10 fitments. Then replace the lamps with LEDs.

PJ

 

[ericmark]

My transformer looks like this

and has been running for around 15 years with no problem. However it's a large unit and no way would it fit through the hole made for the lamp. It's mounted in the loft in free air.

The lamps were fitted as a whim and really they are pointless or rather the reverse they project points of light to no real benefit. The idea is they shine onto the white walls of the bath room and the light is reflected off the white walls. I have replaced all the lamps with 0.58W LED's just so they still look right as the main 11W CFU lights the bathroom ample.

On the other hand the two bedside GU10 lamps work well. Here I use the fact they are spots to light a book one meter from the lamp. This is what they are designed for. And as spot lights on book or picture on the wall they work well but general lighting in the main useless.

I was rather impressed in my mothers house with 2D round light in the kitchen at 28W this works well. Still have lights on cooker hood and some under counter lights but general lighting is all from a single flush with ceiling lamp.

If me I would replace one or two with proper lamps and then fit LED in remaining just to fill the holes unless pods like I have in bathroom unlikely they will light wall and carpet does not reflect light very well.

Converting to GU10 means you can fit tungsten, cold cathode or LED in same fitting so easy to convert back if you want.

The so called transformer you have at moment is really a switched mode power supply and to work they use capacitors which have a limited life with is reduced if they run hot also they have in the main (there are exceptions) both minimum and maximum output the minimum output in the main (there are some lamps which claim to still work) stops you using LED lamps and the voltage is too low for cold cathode lamps to work.

So except for when extra low voltage is required for safety like some areas of the bathroom GU10 would seem best option.

 

[mfarrow]

Here's some of larger sizes which hopefully won't break the bank. http://www.airlinktransformers.com/low_voltage_lighting_transformers/halogen_lighting_transformers/

Be aware that current rating of the cable needs to be suitable, i.e. if you've got 50W at 12V that's 4.17A, and the cable at the start needs to be able to take the whole string.