Fault Finding a LV light Fitting

acvc · Mar 5, 2009

Can anyone telkl me if this is an ok way to test if a transformer is working ok? I don't want to damage it.

Situation: ceiling light fitting with 12 small halogen lamps, all run from a transformer inside the fitting cap, 230V to primary, 11.5V out of secondary side. It's not on the ceiling now, it's on the floor. Would it be ok/safe just to put a plug on the flex and my megger across the output side to check the voltage. If 11.5V reading, then transformer ok?

The thing doesn't work any more. One lamp went and I left it for a few weeks and I suspect that it might have had a bad effect on the transformer, calling for a different load from whet it was designed to offer????????

I've continuity tested through all the other lamps and they are ok.

kung · Mar 5, 2009

Hi ACVC
You say the tranny runs 12 hals and 1 blew i take it none of the others work now ? are they recest lamps or is this a main light ? best way is test under load as could be dropping under load ! or could be cable fault etc.
Regards
Kung.

hughesy · Mar 5, 2009

is there a thermal cut out on the transformer

Spudnik · Mar 5, 2009

If you are confident then yes, powering up the fitting and taking a voltage reading from the output side is a good start.

As Hughesy said, there could be a thermal cutout that may not even reset for some reason.

acvc · Mar 6, 2009

Apoplogies for not replying sooner. I had to dash out.

NO thermal cut-out apparent. Just a circular transformer case, no written mention on it or instructions re thermal cut-out. The only accessible wiring/connection on the transformer are the L-N in and out.

NO. The other 11 lamps continued to work for three weeks till the whole thing packed in, and as far as i can deduce from continuiity testing through each one, they still are working (apart from the original one which isn't).

It's a singular ceiling pendant fitting with multiple lamps (12), not recessed.

Many thanks for replies, apologies once again.