LV Lighting question

Aug 21, 2008 9 Replies

I have some Low Voltage kitchen ceiling lights, each with its own transformer. Recently, one of them has run for about a minute and then gone out. I've checked for overheating which was my first guess, but it's not that. I've also checked for loose connections but no luck there either. Any suggestions?



Regards



Pat Macguire


Syke explained :

Could you perhaps try swapping that particular one for one of the others and see if the fault moves with the 'transformer'?

Most likely it will be the 'transformer' (a switch mode power supply in fact) and the only solution will be to replace it.

It's possible that the bulb you used was of too low a wattage, which means that because of poor transformer regulation the voltage getting to it was too high. For instance, if the fitting is designed for a 50W bulb and you have only a 20W bulb you could be overrunning it, even if the nominal voltage is correct..

Check that the bulbs are the correct rating for the fitting.

bad transformer - assuming the transformer is running a lamp of wattage its specced to

NT

Can't see that causing the PS to shut down then come on again. Unless the OP means the bulb is blowing.

Can you get at the 'transformers' easily? If so swap the affected one with another. Some types fit through the fitting hole so are quite easy to change. If the fault moves with the transformer you have the answer. But my guess is you've got a SMPS rather than transformer type and it's developed a fault. They are so cheap you just replace them.

iF it is a toroid transformer, it may have a fauly thermal trip. Out of about 40 of these I had one DOA and one that overheated once, and ended up like yours. Just replaced both.

I have similar problems with LV lights and transformers basically in the Summer (when its hotter) one or two LC lights goes off after couple of minutes.

One was a faulty transformer, replacing cured the problem.

Other was transformer was lying in the insulation in kitchen roof. Managed to push insulation away and stand the transformer directly on the plasterboard and works fines.

They are so cheap its not worth testing them IMO.

Replace lamp (~50p) and then transformer (~275p).

Thanks for the replies. I have ordered two transformers from Screwfix (1 spare).

Regards

Pat Macguire

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