what size transformer do i need for 10 halogen bulbs for a ceiling light. total bulb watts = 150?

Question

the cup of the light holder is 9cm diameter can anyone suggest what to do . how do i then fit the transformer, what does input and output mean

Answer 1

What happened to the transformer that was originally fitted and connected in the ceiling rose (cup!)? Input is the mains voltage, 230/240 in UK, output is the lamp voltage, probably 12 volts in your case????? 15 watt lamps are a bit uncommon, but if that's what they are then you need an output of 12 volts @ 150va/watts. You will have to get a circular transformer (eg Eaglerise SET 150 CS) to fit within the rose, OR fit an oblong type in the loft space above the light if there is a loft? Otherwise contact an electrician to do the work safely.

http://www.sunrise-trafo.de/Daten/Beleuchtungcomponenten/English/SET150-210CS-160CK-Eng.pdf

Answer 2

This question implies that you are wanting to fit a set of 12v lights into an existing 240v household lighting system. The transformer is connected to the mains lighting supply at one side and the other side is connected to the first light. Hence the term input /output. Make sure that you can gain access to the transformer when fitted because in time they can fail and therefore need replacement. The transformer will need a minimum capacity of 150 because it looks like you have 10 x bulbs at 15w each. When you buy the transformer ask the guys on the electrical department to help you with some advice, you should find that they are quite helpful.

Answer 3

In our house there is one small transformer for each 12v bulb .
The transformer pokes through the hole, and sits above the ceiling, so each bulb is controlled by it's own transformer.
I notice on the packaging that one transformer will drive 3 lights, so you can power 9 lights with 3 transformers if you wish to save a few shillings, but in view of access ( lifting floorboards, carpets , moving beds etc ) I think our arrangement is just fine.

Answer 4

Ohms law says that watts = Current x Volts. if you have 12 volt bulbs, then the current drawn by the transformer will be 150 divided by 12 = 12.5 Amps, however you dont say the voltage of the bulb so this calculation would be wrong for any other voltage. Get an electrician

Answer 5

150W. is your answer.
The transformer will be rated in KVA. or VA. which
for incandescent lamps is equal to KiloWatts or Watts.
Anything of .15 Kva or larger, (not too much), that
produces the proper voltage will serve.

Do you really have 10 lamps that add up to only 150W. ?

Answer 6

A small size transformer such as Bumblebee or Jazz would suffice. Anything larger would be an overkill.

Answer 7

Seeing as you don't know input from output, it may be wise to ask someone who knows what they're doing to help you out, especially as it's electricity you're fiddling with.