Faulty switch?

[Jameswren]

Soooooooo...... back to the question.

The three previously working lamps were fine when I left yesterday and no issues reported since (I don't live at the property).

Several of the "experts" at B&Q said to replace the white box/transformer thing with one of these.....

Untitled

• Jameswren
• 12 May 2014
• 1

Does that look like the right thing? Different ratings to what is currently fitted.

 

[333rocky333]

you seem to have missed the point of the last 5 pages

Dimmer, lamps and transformer have to be compatible.

your gonna introduce a transformer that the makers themselves cant quarentee will dim unless you use there specific dimmer.
That specified dimmer may or not be compatible with the other 3 transformers you have.

You need to find out what dimmer the existing 3 require, then get a new tran of the same dimming spec.

Alternatively buy a transformer that states Dimmable with ANY type of dimmer

You are aware the one you showed on page 1 is from screwfix, direct (SFD) you proberly can get the same one plus dimming instructions from them

 

[winston1]

you seem to have missed the point of the last 5 pages

You seem to have missed points as well. They are not transformers. They are switch mode power supplies.

 

[333rocky333]

you seem to have missed the point of the last 5 pages

You seem to have missed points as well. They are not transformers. They are switch mode power supplies.

Give it a rest, you just confuse the OP.
It clearly says on it TRANSFORMER and as john says its recognised throughout the lighting industry and you alone wont change that.

 

[EFLImpudence]

As I've said before,

if the manufacturer called it a sausage it would be a sausage no matter what came before.

 

[winston1]

you seem to have missed the point of the last 5 pages

Dimmer, lamps and SMPT have to be compatible.

your gonna introduce an SMPT that the makers themselves can't guarantee will dim unless you use their specific dimmer.
That specified dimmer may or not be compatible with the other 3 SMPTs you have.

You need to find out what dimmer the existing 3 require, then get a new SMPT of the same dimming spec.

Alternatively buy an SMPT that states dimmable with ANY type of dimmer

Personally I think that optimal compatibility statement is a sales gimmick to make you buy their equipment. If it states dimmable it will almost certainly work with your dimmer if the others do.

Rather like a Tesco recipe book telling you to buy Tesco ingredients.

 

[333rocky333]

Personally I think that optimal compatibility statement is a sales gimmick to make you buy their equipment. If it states dimmable it will almost certainly work with your dimmer if the others do.

But if they said it would work with any dimmer then they would sell more transformers.

The best selling tranformer in the world is the osram halotronic mouse

http://www.osram.co.uk/media/resour...-halotronic-for-low-voltage-halogen-lamps.pdf

 

[Jameswren]

you seem to have missed the point of the last 5 pages

Is that directed at me?!

I have missed most of the point of the last 5 pages because it hasn't been at my limited level of knowledge. I'm happy to admit that.

The point I was trying to make was that it's worked fine for a long time and suddenly stopped - seems to make sense to just replace the faulty equipment.

The set-up and equipment have worked fine for 5 years so I don't see the issue with how it's been done - am I ok to replace the "white box" with the one suggested at B&Q or should I be looking for something else? If I need something else, where can I get it?

 

[JohnW2]

The set-up and equipment have worked fine for 5 years so I don't see the issue with how it's been done - am I ok to replace the "white box" with the one suggested at B&Q or should I be looking for something else? If I need something else, where can I get it?

As I understand it, that's what no-one knows for certain. That Varilight 'transformer' suggested by B&Q says that 'for optimal compatibility' it should be used with a Varilight dimmer. As has been suggested, that could well just be 'marketing hype', but it's also possible that it means that it would not work (at all, or satisfactorily) with at least some non-Varilight dimmers. You could just gamble, and there's a pretty good chance that it would work.

Kind Regards, John

 

[Jameswren]

Ok, seems I'm the expert then

I'll give it a go and report back.

Thanks for the useful bits of help, it's much appreciated.

 

[securespark]

Give it a rest,

https://www.youtube.com/watch?v=i1fOZjiDaw4

 

[winston1]

Another thing, the transformers used for 12v halogen lights have poor regulation and will over volt is not run at full load. Running a 20 watt lamp on a 50 watt transformer will shorten the lamp life. That is one advantage of a SMPS.

12V 50W lamp

12V 20W lamp

Wow the voltage is constant. More poppycock from winston.

Hi, I've just repeated your experiment using a 50VA toroidal transformer and a decent 3 1/2 digit digital multimeter. Results:

No load 14.06v
20w load 12.98v
50w load 11.92v.

Seems it is not poppycock after all!

 

[bernardgreen]

Hi, I've just repeated your experiment using a 50VA toroidal transformer and a decent 3 1/2 digit digital multimeter.

Try it with a decent transformer.

Hint. IR losses in both the windings and eddy currents in the core waste a few watts. The amount of wastage is almost directly proportional to the load. The wasted watts heat the transformer. The proportion of power wasted is higher in "economy" transformers and the maximum rating is set by how much wastage the transformer can safely dissipate as heat.

A decent transformer with low IR low losses ( larger diameter wire in the windings ) will not have the variation in output that yours has.

 

[winston1]

Try it with a decent transformer.

Hint. IR losses in both the windings and eddy currents in the core waste a few watts. The amount of wastage is almost directly proportional to the load. The wasted watts heat the transformer. The proportion of power wasted is higher in "economy" transformers and the maximum rating is set by how much wastage the transformer can safely dissipate as heat.

A decent transformer with low IR low losses ( larger diameter wire in the windings ) will not have the variation in output that yours has.

Hang on a sec. I originally said:

Another thing, the transformers used for 12v halogen lights have poor regulation and will over volt if not run at full load. Running a 20 watt lamp on a 50 watt transformer will shorten the lamp life.

Note again:
the transformers used for 12v halogen lights have poor regulation

Nothing about a "decent" transformer but the ones normally used. I think I've made my point.

 

[DaftPunk]

All you've proved is that you're a google warrior. All the lads on here with actual experience of electrical work disagree with the nonsense you continue to spout.