Another LV Halogen question !

[Angela]

In my hallway I have 3 LV halogen downlighters. The middle one went so I replaced the bulb only to find that it still didn't work! I presume that the transformer has gone and I also presume that each light must have their own transformer as only one has gone. How easy it to replace a transformer? I haven't tried to get the light fitting out yet but I hope that they will have put enough length on the wire to allow me to pull it all through the hole and replace it - am I being too hopeful or am I going to have to go through the boards upstairs?

The house is only 1 year old - I would have expected a transformer to last longer. Is this a common problem or is it just the fact that the builder has used crap transformers? Is there a difference in quality - which type would you recommend?

So many questions!!

TIA

Angela

[Roger Mills]

You first need to determine whether the lamps *do* have individual transformers - or whether they are all fed by a single transformer. If the latter, one lamp could fail to light if there were a wiring fault between the transformer and lamp.

You'll need to get the fitting out to find out. Most such fittings are held in by a couple of spring clips which spread out above the ceiling. If you first remove the bulb (probably held in by a circlip) you should be able to pull down on the rim and remove the fitting. It should then be pretty obvious as to whether or not it contains a transformer.

Roger

[Lawrence]

I would be surpsied to have separate transormers in this case. What power lamp?

Some setups have a fuse panal to fuse each lamp separatly. Some transformers have separate outlets.

If the house is under a year old I would expect the transformer to still be under warranty.

Lawrence

usenet at lklyne dt co dt uk

[N. Thornton]

could be. Could be a wire come loose, a boken bulb socket, a gone mains fuse, or less likely a dud replacement bulb.

depends why its gone.

easy.

it depends, if the TF is next to the light its easy. If youve got one TF feeding 3 lights you wont need to access the TF anyway.

I'd determine the cause first.

If you want max reliability, an iron transformer, not an electronic one. Any kind should do though, as long as your lights arent on a dimmer.

Regards, NT

[The Natural Philosopher]

Transformers if overheated often cut off on their own, and need to cool down. I have a rougue one whoch works for 5 minutes and then is dead unless switched off for at least 4 hours.

Replaeing it tomorrow with luck..

Anyway, you may simply have a duff transformer, not a blown bulb at all.

I tend to use toroidals - I got mine today from Newwy And Eyre, and the

nice thing about toroidals is that they don't wear out or blow up.

They just switch off if too hot - and they don't cause radio interference.

[The Natural Philosopher]

Its very common if replacing existiong mains lights, as there is no need that way to run LV wiering everywhere, and the cost is in fact very little different.

[Angela]

They are 50W lamps. A second one has gone, this time in the kitchen - both within 3 days of each other so I am expecting more to go and I have 13 of them altogether throughout the house. I have taken both the lamps out and they have individual transofrmers so that should make it an easy job....................looks like I had better make a bulk purchase, screwfix looks the best buy.

Angela

[Harry Bloomfield]

On 01/12/2003 "Angela" opined:-

There are various ways that it could have been done..

There could be one tranformer per lamp or one single tranformer for all three. It is also possible that transformer have not been used, it could be an electronic unit instead.

A common problem with the low voltage lights is connections burnt out. Sometimes the actual lamp sockets burn sometimes connections along the wiring. They do carry quite a high current.

[Rob Bradley]

haven't installed them yet and I'm a bit unsure now - especially as my parents-in-law's house burnt down recently because of an electrical fault (not LV lights.) Surely they can't be that dangerous, they seem very popular these days and there must be millions in use.

Rob

Remove gloves to type a reply.

[The Natural Philosopher]

Both my track uints went weird after bulb failures. Turned out that teh clip together contacts between the transformer and rails was dodgy. I had to dismantle, sand off the chrome oxides, and reassemble...

They did in fact 'burn out' but not in teh way you mean...

[Owain]

"Rob Bradley" wrote | Surely they can't be that dangerous, they seem | very popular these days and there must be millions in use.

So are chip pans ...

Owain

[Rob Bradley]

I know, I had the fire brigade out to mine once. QED.

Rob

[Harry Bloomfield]

On 17/12/2003 "Rob Bradley" opined:-

The lower the voltage, the higher the current has to proportionally be for the same wattage of lamp. High current flow means connections have to be good or they will heat up.

I actually meant burnt out in the sense of interconnections becoming burnt out. A common failing of the 12v systems is the lamp holders burning out, or the pins of the lamp itself. The heat generated carbonises the insulation and or the metal, producing arcing. In such a situation it is certainly possible that a fire could be started.

The thing to watch out for is to make sure the connections are good and to keep an eye on low voltage lights for the flickering, which would indicate a developing problem.

Having said that, I have a number of low voltage lights installed around the house ;-)