Downlight transformer

[new_DIYer]

Hi

I have 4 downlights in a room which currently have MR16 halogen bulbs fitted.

I am wanting to swap these for LED bulbs, keeping the housings. However, they have a TCI Saronno W.X 105/240 transformer fitted to each light.

My question is, can I change the halogens to LED? If so, any recommendations or information please.

Thanks

 

[Taylortwocities]

Yes. Use 230v LED lamps. Then you do not need a transformer or other LED driver.

Meerkat

• Taylortwocities
• 11 Dec 2009
• 53

Simples!

 

[333rocky333]

To remove or change the transformer you would need to take at least 1 fitting out to access it and still have to amend the existing wiring, as well as buy Led lamps, so you may as well consider measuring the hole and getting new 4 Led fittings with built in drivers that are far more reliable and safer than using 240v lamps in fittings designed for 12 volts.
As for 12 volt LED lamps they appear to be a bit hit and miss and more so with a 105va transformer and if dimmed even more problematic

 

[ericmark]

Doing a google on "TCI Saronno W.X 105/240 transformer" it would seem minimum wattage is 35 and you are unlikely to find LED lamps that big, even running all 4 from on unit unlikely to find LED lamps large enough. So as others have said best option is to convert to low voltage (230) and do away with transformers.

The other option is to swap for these Toroidal wire wound transformers.

 

[ericmark]

Half my reply disappeared, there are devices called electronic transformers which are rated 0 - 50 VA with kHz output and devices called drivers which are also switch mode so small enough to fit in the hole, however most of the 12 volt LED MR16 replacements I have seen are rated 50 Hz so although they may work, you have no guarantee. Although the LED is a current dependent DC device, once put into a package as with the MR16 it is normally a voltage dependent device and it will have some form of built in driver. It is the driver built in which is the problem, it may need smooth DC 10 - 30 volt (often used in caravans) or an AC supply (more normal) and with an AC supply it has many options as to how to limit the current including some where frequency is important.

Mine are clearly marked 50 Hz so should not use a 0 - 50W electronic transformer or a 12 volt driver (not really transformers or drivers but that is the names used.) as first is in kHz range and second is DC. However likely both will work, but be aware you are taking a chance so one at a time, don't do the lot together.

 

[Taylortwocities]

Half my reply disappeared

Maybe you exceeded the maximum message size limit

 

[new_DIYer]

Thanks for your replies.

This is the transformer as fitted.

 

[new_DIYer]

Right, so many different answers.

It states “transformer” on it?

The manufacturers website states it is a transformer.

 

[ban-all-sheds]

Right, so many different answers.

Indeed, but not conflicting ones.

It states “transformer” on it?

No - it states "electronic transformer". Just like electronic mail is not the same thing as mail, and an electronic cigarette is not the same thing as a cigarette, an electronic transformer is not the same thing as a transformer.

The manufacturers website states it is a transformer.

Not "electronic transformer"?

Anyway - firstly, as your photo shows it has a minimum load of 20W, so an LED would not be large enough.

The photo isn't very good, but I can't see 2 lines after 12V, so it doesn't have this:

I think it has the symbol for AC, but it won't be 50Hz.

So do the lights you want to use need DC, or 50Hz AC, and are they less than 20W? If you answer 'yes' to any of those you'll need new power supplies.

 

[Taylortwocities]

Use 230v LED lamps. Then you do not need a transformer or other LED driver.

 

[JohnD]

quite right. LEDs have improved so much that there is no need for the cost and complexity of transformers.

 

[bernardgreen]

quite right. LEDs have improved so much that there is no need for the cost and complexity of transformers.

Have they improved. Some of the reputable manufacturers have improved quality. But it is an unavoidable fact that an LED element requires a controlled CURRENT to be driven through it. Unlike a filament ( incandescent ) lamp one cannot just apply a controlled voltage to the LED element and let the element control the current. (*)

Hence between the 230 volt AC mains and the 3 to 4 volts DC voltage across the LED element there has to be a power comversion device. What os that device if is it not an SMPS labelled either "electronic driver" or "electronic transformer".

On a 230 V LED lamp that SMPS is built into the lamp between the 230 V input terminals and the LED element.

To make a small compact 230 V LED lamp requires a small compact SMPS module to be fitted as part of the lamp assembly. Compact SMPS modules can be made even smaller if filtering and shielding to reduce EMC ( spurious radio frequency radiation ) from the midule are not included in the design

(*) there is one exception, some LED elements are constructed with a layer of resistive semi-conductor included as part of the element. Typically these LED elements are intended for use in very low power decorative lighting strings where the 3 or 4.5 volt battery is connected directly to the LED elements wired in parallel along the string

 

[bernardgreen]

I think it has the symbol for AC, but it won't be 50Hz.

Pulse modulated output which when applied to a resistive load will have the same effect over time as a smooth DC voltage of the stated voltage.

Pulses may be any voltage, pulse rate and mark space ratio. A 12 volt supply so marked might have pulses of 30 volts and a mark space ratio of 1 to 3. OK for an incandescent lamp, probably fatal for an SMPS driver built into an LED lamp.

 

[ban-all-sheds]

I doubt that a 12V LED lamp (whether expecting 12V DC or AC) would have an SMPS built into it.

 

[aptsys]

I doubt that a 12V LED lamp (whether expecting 12V DC or AC) would have an SMPS built into it.

Generally they do, anything else would be horribly inefficient.