Low voltage lighting probs.

[Pianoman444]

HELP! I'm trying to run 3 x 35w 12v from a transformer (250va) which I've metered and is telling me it's 12v on the output. I've also metered the individual light housings which are all 12v. Cuh........ so can anyone tell why every time I connect a halogen, it blows immediately. I know I've obivoulsy done something wrong but can't see what!

 

[Spark123]

What voltage are the lamps?
Are you touching the quartz part of the lamp with your fingers?

 

[Pianoman444]

What voltage are the lamps?

Hey, quick response. 12v and they are mr16 enclosed

 

[Spark123]

Are they cheap lamps? It is strange that as you have a 12v supply that they blow immediately, it doesn't sound like you have anything wrong.
Faulty lamp bases can cause problems but not normally instantly.

 

[breezer]

how are you connecting them?

picture?

Picture info is in forum information

 

[Pianoman444]

Untitled

• Pianoman444
• 9 Nov 2008
• 1

Homemade effort. Transformer is one that was used for a show/events lighting company and has been pac tested.

 

[breezer]

very silly. I LIKE it.

what exactly happens when you try to connect any light?

from what you have said so far there is a short, have you a multi meter?

 

[Pianoman444]

Thanks. I've made up 2 of them for a piano showroom. Thought they would light up the inside of the grands nicely. That is ....... if they worked.

Glows bright and pops all within a nanosecond. I have tested all 3 units with a meter and it reads 12v on each.

 

[Spark123]

Are they cheap lamps?

 

[ban-all-sheds]

from what you have said so far there is a short, have you a multi meter?

Can't see how that would take out lamps.

Transformers, yes.

Switches, cables, MCBs/fuses, yes.

But not lamps.

 

[breezer]

how can it read 12v if it only lasts a "nanosecond?"

are you able to use the same lamp again all be it a short while later?

i was thinking a shhort, you havent checked for this have you

 

[RF Lighting]

Are the birdies second hand?

Does this happen with every single fitting, or just certain ones?

 

[breezer]

i was going to suggest something simialr.

since you made it, take one light fitting out and try it.

Sorry but its crunch time.

I do like the lights, but if you can not figure what is wrong, i have to ask are you qualified to make them and install them since you did say they are for a piano show room.

In todays society if anything goes wrong insurance will pay out, then claim it from or sue YOU

 

[Pianoman444]

The birdies as brand new. Tried halogens on 2 of the birdies, haven't tried the 3rd. The stem which I made carries no electrical current. Only the wires travel up through the main stem all soldered and covered with heat shrink. Ok, nanosecond is maybe a bit quick but certainly no more than half a second. I have a friend (a sparky) who is on holiday for 2 weeks, but really wanted to sort this meself. So I will get it checked out by a qualified electrician when he gets back. But.... it is or should be as simple as wiring a plug.. I would have thought. Thanks for all the replies.

 

[ban-all-sheds]

AFAIK the only way (apart from physical abuse) to make a lamp rated at X volts burn out almost instantaneously is to connect it to a supply which is significantly more than X volts...