LV Transformers for Lighting

[elziko]

I'm thinking of getting one of these 0-250W trasformers for lighting:

'm planning to run a total of 250W of lighting from it. It does say I can use it up to it's maximum rating but I wondered if it is generally avoided?

TIA

[Andy Hall]

I generally run electronic transformers at about 50% of max rating. This is enough to be comfortably above the minimum level, while not running them flat out either.

Two other points.

- With one device you will have a single point of failure. Use two and if one fails only half the lights are gone.

- You may have to look carefully at the LV wiring. Some transformers specify a limit of no more than 2-2.5m for the LV wiring. The wiring routing may be tricky as well. With a 250W transformer at 12v you have to allow for over 20A and achieve low volt drop. It may be tricky to cable to achieve these requirements.

Considering that the transformers are so inexpensive, it would be better to use more than one, locating them closer to the lamp fittings.

[The Natural Philosopher]

I've got one identical or remarkably similar buried in a stud wall running 3x50W lamps. No troubles AT ALL. Dims a treat too. The dimmer also supplies another electronic transformer for a further 3x50W LV lamps. 400W dimmer.

Run fairly cool.

I think they are pretty good actually.

[The Wanderer]

I'll second all of that. I have 11 lv downlighters in my kitchen, each one running a 35w bulb. Each has its own t/f, on the grounds that if you get a failure, it's one light gone. Do it your way and if the t/f goes, you're without lights until you can get another.

Oh, and FWIW, one t/f did fail after only a couple of weeks in service. I don't think this is especially a problem with electronic t/fs, as I have several others in different situations all been running quite happily.

All credit to tlc, it was replaced immediately FOC.

[Pete C]

Sounds good, tho make sure it's easy to get to if need be.

250W is rather a lot for one room, generally, I'm sure there is a lighting wiki somewhere which will cover some alternatives.

cheers, Pete.

[The Natural Philosopher]

My kitchen nedes about 600W, in incandesent terms.

I figure about 20W/sq meter.

[Pete C]

Don't know about your kitchen in particular, but there seems to be a trend for dark floors, dark worktops, and lots and lots of downlighters, plus under cabinet lights, etc.

cheers, Pete.

[Andy Hall]

I don't think that darker surfaces is particularly new as a concept ( I did this about 5-6 years ago). Having a goodly number of halogen downlighters with selective switching is very effective with them however.

[meow2222]

[John Rumm]

I have used these as well, and not had any difficulties. One thing to beware of with the higher rated ones is you need enough load on them if running a dimmer. For example, using a 250W one with a load made up of 4 x 50W lamps, you only get correct operation with at least three lamps installed. So you may need to take care not overdoing the spare capacity.

[Si]

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