Replacing a big toroidal transformer on spotlights

[dogbait]

We've been running three of the below Philips GU5.3 5W 76954500 spotlights in our ceiling for the past 5 years:

https://www.amazon.co.uk/gp/product/B00KTUZCB8/

They replaced 50W 12V halogen spotlights, each with their own transformer. We kept the existing 20+ year old toroidal transformers in place. Alas one of the transformers died.

Reading about what to buy to replace it, I see a lot of options - another wound transformer or a constant current or constant voltage driver, then there's the potential pitfall that some GU5.3 bulbs present themselves as 50W halogens to the transformer so in fact prefer wound PSUs vs switching.

Also it seems some LED drivers flicker if they don't have enough load on them ie. multiple bulbs?

I'm unsure what to fit now, I see the Aurora DA-E60 here - it requires a 20W load - which has me confused - does the 5W Philips spotlight I have appear as a 5W load or a 50W load?
http://www.discount-electrical.co.uk/section.php/109012/1/aurora-lighting-dias-transformers

There are also a few constant voltage drivers here:
http://www.discount-electrical.co.u...ora-lighting-12v-constant-voltage-led-drivers

I supposed the 25W one will allow me to drive all three bulbs (in parallel ofc)?

Any suggestions appreciated since I can't find much on Philips website about what type of driver their spotlights need.

 

[sircerebus666]

Another option is to use gu10's instead of 5.3's then you could scrap the transformers all together

What room is this in?

 

[delmel]

I would change over the holder to GU10 and buy the led as they are easily available everywhere. Do not use the first option a transformer shouldnt be used on an LED, it should be a driver. Although yours has run and lastes a considereable time, they are not designed for each other and it will likely if works shorten the life of transformer and the lamp.

 

[ericmark]

I noted my G5.3 MR16 LED replacement have clearly marked on them 50 Hz, so clearly the only option would be a toroidal transformer, however I am sure they would work on DC without a problem, and likely will also work with kHz AC supply with the more modern switch mode electronic transformers which will supply from zero.

If only needing to replace one This one would seem to be best option can't see point in swapping one odd one to 230 volt may as well have them all the same.

However as @sircerebus666 and @delmel says using GU10 is today generally the better option, the problem with G5.3 is there are so many odd variables, in my caravan for example they are DC 10 - 30 volt designed to run off a battery, buying from the high street however most at 12 volt 50 Hz so are for an AC supply. But using the internet you can get all sorts of voltage.

 

[bernardgreen]

Philips GU5.3 5W 76954500 spotlights ~~~~replaced 50W 12V halogen spotlights, each with their own transformer.

It is very likely that one of your 50 Watt toroidal transformers can supply all three of your 5 spotlights. Toriodals like all wound transformers do not have a minimum load.

Do not use the first option a transformer shouldnt be used on an LED, it should be a driver.

Mis-use of terminology has created a mine field.

An LED lamp has one or more LED elements and one or more drivers. ( there are a very few exceptions to this )

LED elements convert electrical current into light and heat. The amount of current that flows through the element determines how much light and heat is produced. Too much current and the LED element over heats and is destroyed.

An LED element cannot control the current that flows through it. The current has to be controlled by a driver that drives the correct current through the element.

The simplest driver is a resistor in series with one or more LED elements together with a DC supply of a controlled voltage.

This is two modules cut from a 5 metre strip that requires a 12 volt DC supply.

Using more elements in series allows for higher supply voltages. This method, with about 80 elements in series, can be used for mains voltages in cheaper lamps.

Most drivers are a switched mode current source that will drive a predetermined current from their output. The voltage on the output of a driver is the voltage needed to force the required current through the LED elements being driven.

Almost all items sold as LED lamps are in fact a combination of a built in LED driver supplying ( driving ) a controlled current through one or more LED elements.

An external LED driver ( controlled current ) cannot be used as the power supply to a LED lamp. The external LED driver will force its rated current through the driver in the lamp irrespective of the current the driver in the lamps requires. If the internal driver is not taking the external driver's rated current then the external driver will increase the voltage on it's output to try and force it's rated current through the driver in the lamp.

This results in the voltage from the external driver becoming much higher than the rated supply voltage of the lamp and premature if not instant damage to the electronics in the lamp.

 

[winston1]

Since the existing toroidal transformers must be rated at 50W simply wire all three lights to one of the good remaining ones leaving a spare for the future.

Toroidal transformers rarely fail. I would investigate what has actually happened to the “failed” one.

 

[bernardgreen]

One caution

If the lamps are suspension wire lamps like these

or similar then you should NOT use a Switched Mode Power Supply ( SMPS ) as the suspension wires act like aerials and radiate the high frequency electrical "noise" from the SMPS.

The length of cable between an SMPS and a lamp should be as as short as possible and preferable a twisted pair instead of side by side twin cable