How to check if spotlights are AC or DC?

[winston1]

What should we call a thing that converts 230 (sorry 240) volts AC into 12V dc? It's a box containing a transformer plus a rectifier and a few capacitors. I've always called them transformers. A switch mode PSU also contains a transformer, so what is so wrong about calling them transformers?

You have always been wrong. By definafion (see earlier) a transformer does not change frequency and DC is zero hertz. The correct name is DC power supply.
Likewise your switch mode PSU is not a transformer as it changes frequency.

Please learn from your mistakes and use the correct term.

 

[JohnW2]

What should we call a thing that converts 230 (sorry 240) volts AC into 12V dc? It's a box containing a transformer plus a rectifier and a few capacitors. I've always called them transformers.

I, and I think most other people, have always called them PSUs! To have "a transformer", one of the components which was a transformer, really would be confusing! ... it's a bit like the funny looks I got when (as previously reported here), and 'experimentally', I went into Halfords and asked where I could find a lamp for my headlamp, and into B&Q and asked where I could find a lamp for my (table) lamp

A switch mode PSU also contains a transformer, so what is so wrong about calling them transformers?

As above, no more wrong than called a traditional PSU a "transformer"

Kind Regards, John

 

[EFLImpudence]

No Winston, you cannot say "by definition".

Your (or the) definition of your 'genuine' transformer is just a definition of your 'genuine' transformer at the time.

The English word 'transformer' simply means 'that which changes something' therefore it can be used to describe anything which changes anything.

The railways transformed Britain, therefore the engineers who built them were transformers.


As I mentioned, driver.
The word driver is used for many things. To restrict it to whichever was first would now be as pointless.

 

[winston1]

Not my definition. It is the IECs definition at this point in time.

You are confusing the word transform with transformer.

Railway engineers certainly were not transformers.

 

[eveares]

Bit late in here, but here goes...

But it seems that you cant replace halogen with LED unless they are on DC circuit.

Not true, check links out below. The main issue is toroidal and other older transformers/SMPS's having a minimum load they can handle.

12V MR16 Dimmable 7.5W (50W equivalent) 2700K

12V MR16 Non-Dimmable 7.2W (50W equivalent) 2700K (Data Sheet) (Using 7 of these myself, very happy - Using them will modern SMPS.)

12V MR16 Dimmable 7.5W (50W equivalent) 4000K (Data Sheet)

12V MR16 Non-Dimmable 7.2W (50W equivalent) 4000K (Data Sheet)

Is there any easy way to test for AC DC before buying the LED bulbs?

The power source can easily be checked with a multi-meter that has a built in frequency setting that can measure in the KHz range. This or This will do for a Digital Multi Meter; know not ideal, but could not find any budget DMM's with a high frequency setting built in from local places like ScrewFix, Maplin, TLC, etc...

For the AC/DC compatibility of the bulb, you will have to check the bulbs data sheet.


Also a "load capacitor/s" may? work for some older SMPS's that have a low load limit, but others on here are better informed than me in which scenarios load capacitors can be utilised.

Regards: Elliott.

 

[EFLImpudence]

Not my definition. It is the IECs definition at this point in time.

It's just one definition. You could inform they are out of date.

You are confusing the word transform with transformer.

No, I'm not. One is the verb and one is the noun which does it.

Railway engineers certainly were not transformers.

They certainly were - not wire-wound iron cores, though.


There are even toys called transformers.

 

[ericmark]

A transformer

covers many items, but with electrics we normally consider wire wound units which isolate, change voltage, convert current into voltage, and also those which don't isolate all as transformers. Where there are extras then there is not real point where we can say it is no longer a transformer, be it a case, a rectifier, or a complete host of electronic components. Wire wound items also include chokes and ballasts and there is no real difference between a tapped choke or a auto transformer except for where they are used. Since the one in question is transparent you can see the transformer inside. Maybe a better term would be power supply?

However that does not help, what does help is knowing the smallest lamp it can power is 20W. So either the unit needs to power a group of LED lamps to get the 20W load, or the unit needs replacing. Today you can get pulse width modulated power supplies which go form zero to 60W so you could replace it with a unit able to work either a LED or quartz lamp.

In real terms there are three ways forward.
1) New power supply, be it toroidal core, new type PWM which will go to zero current, or a DC supply.
2) Re-wire so many LED's fed from one "Electronic transformer".
3) Move from extra low voltage (12v) to low voltage (230v) lamps.

The reason for 12 volt or separated extra low voltage (SELV) was two fold.
1) To extend the life of the quartz lamp.
2) Extra safety in special locations like bathrooms.
If the latter then you are stuck with extra low voltage, but with the former using LED all the advantages of using ELV have gone, in fact I have found the 230 volt LED lamps last longer than the 12 volt versions.

There are special DC versions of the G5.3 lamp, mainly for use with caravans and the like, they do have a really good lumen per watt, normally 100 lumen per watt, and a voltage range of 10 ~ 36 volt. However they are expensive compared with the standard domestic model. The standard domestic model is between 60 and 80 lumen per watt, until reading the advert on this post I had assumed AC or DC, but that bulb clearly says 50Hz so is AC only. With AC they can use a capacitor to limit current, with DC that would not work, but with a capacitor the frequency would matter, so a switch mode unit working in the kilohertz range would be no good.

I think it unlikely that the lamp would use a capacitor, and think unlikely it really has to be 50 Hz, but it states 50 Hz on the bulb.

After the premature failure of my G5.3 spot lights after changing to LED, when no other LED lamp in the house has every failed, I would only use G5.3 LED spot lights if no other option. And I would try to use a smooth DC supply and DC lamps.

 

[mameha]

I have emailed aurora and waiting a reply to see if there is a compatible LED bulb.

Some further info:
- none of the bulbs are directly over the bath or shower (there are two separate extractor fan + light units there)
- The 'transformer' in the photo had a brother nearb, these are connected directly to the two spotlights in the ensuite.
Next door, there is a bathroom with three further spotlights, I could not lift the floorboard completely but it looked like *maybe* the bathroom sportlights are also connected to these same two transformers as there were the same thick grey wires running around and I could not see any transformers. The bathroom takes the same GU5.3 bulbs. In other words potentially 2-3 bulbs are connected to each 'transformer' hence higher load than I originally suggested.

This is all much more complex than I expected, so I am kind of resigned now to either keeping the halogen bulbs or getting a sparky in to quote the work. If it means changing everything, the transformers and bulb holders and bulbs etc I assume this is going to cost more than £100 which would not be cost efficient.

 

[securespark]

It is very unlikely the two bathrooms share transformers, unless both sets of lights go on together when you switch the light switch on.

This would obviously be highly inconvenient so the transformers will only feed lamps in their respective rooms.

 

[mameha]

Thanks, they have separate light switches.
I couldnt see very well what was going on with the bathroom spotlights.

 

[winston1]

I have emailed aurora and waiting a reply to see if there is a compatible LED bulb.

Some further info:
- none of the bulbs are directly over the bath or shower (there are two separate extractor fan + light units there)
- The 'transformer' in the photo had a brother nearb, these are connected directly to the two spotlights in the ensuite.
Next door, there is a bathroom with three further spotlights, I could not lift the floorboard completely but it looked like *maybe* the bathroom sportlights are also connected to these same two transformers as there were the same thick grey wires running around and I could not see any transformers. The bathroom takes the same GU5.3 bulbs. In other words potentially 2-3 bulbs are connected to each 'transformer' hence higher load than I originally suggested.

This is all much more complex than I expected, so I am kind of resigned now to either keeping the halogen bulbs or getting a sparky in to quote the work. If it means changing everything, the transformers and bulb holders and bulbs etc I assume this is going to cost more than £100 which would not be cost efficient.

How many more times? They are NOT transformers. You come on here for advice then totally ignore it. Again, they are NOT transformers. They don't have transformer written on them because they are NOT transformers.

 

[mameha]

I did use quotes around the word!

 

[JohnW2]

How many more times? They are NOT transformers. You come on here for advice then totally ignore it.

The OP came here for advice on lighting, not language. It's arguably not unreasonable for you to point out once that at least some people regard the terminology used as being incorrect, but to take on a school-master role and criticise someone for not taking that (unsolicited) 'advice' (particularly when (s)he subsequently put the word in quotes) is, IMO, inappropriate.

Kind Regards, John

 

[333rocky333]

They don't have transformer written on them because they are NOT transformers.

ERR its got TRANSFORMER written on it!
As well as indicating it can run some LED

It goes on to state that if used with LED lamps rapid flashing is indication of TRANSFORMER overload.
You are rude and insulting to posters

 

[winston1]

On the photo the OP supplied where does it say transformer?

I'm not rude or insulting.

I explained several times that what he had were not transformers. If anything he was insulting by continuing to refer to them as transformers.