Led downlighters flickering

[assegayer]

Hi guys,
Had a little job today where some led downlighters were flickering it was 3 out of about 15. I checked the voltages on the 3 which told me the transformers for each one are broken. Confirmed this by testing a working one which was a getting a steady 11.5 to 12v ac.

I was just wondering what possibly could have cause these three transformers to blow. There is no insulation or anything obvious causing them overheat. Was thinking maybe loose connections.

Relatively new build i woud say 5 years max
Any ideas?


Side note: i attached pic of transformer. Secondary ouput says dc however when i test on dc setting get nothing when i switch to ac i get a reading.

Also where do they sell some decent tranies with the same specs?

 

[rolyberkin]

6W LED Transformer for 12V Spotlights and Strip Lights from LED Hut - https://www.ledhut.co.uk/led-driver-transformers/6-watt-led-transformer-driver.html

They currently have a £10 off your order.

 

[assegayer]

6W LED Transformer for 12V Spotlights and Strip Lights from LED Hut - https://www.ledhut.co.uk/led-driver-transformers/6-watt-led-transformer-driver.html

They currently have a £10 off your order.

Thank you very much for your reply. The transformer for some reason as shown in the pic i attached says secondary is 23 to 38v dc does it make a difference..i know this may sound silly but when i measured i had to set my meter to ac to get a reading

 

[Midwest]

Its a profitable market making transformers/drivers!

 

[freddo]

The 23-38V means the unit is a constant current device, It will ramp up the voltage until the current drawn reaches the rated output of 250mA. This allows for a number of series connected LEDs to operate correctly, the AC output you measured may be because the output is pulsed DC or just not very smoothed.
I would be searching for a 250mA constant current 'led driver' as a replacement. Have you checked the LEDs? They are not as reliable as they are advertised.

 

[assegayer]

The 23-38V means the unit is a constant current device, It will ramp up the voltage until the current drawn reaches the rated output of 250mA. This allows for a number of series connected LEDs to operate correctly, the AC output you measured may be because the output is pulsed DC or just not very smoothed.
I would be searching for a 250mA constant current 'led driver' as a replacement. Have you checked the LEDs? They are not as reliable as they are advertised.

Thank your detailed response i definetly tried different bulbs in them and it still didnt work. Then measured the output from the fault tranies and cross referenced with the healthy trannies and it was significantly different,constantly fluctuating badly.

So it wouldnt really matter if i got ac ones ? Also are they really this expensive like £6 a piece?

 

[freddo]

No you need a proper constant current LED supply, AC will quickly do the LEDs in, a standard 12v lighting transformer will not work. What brand/model are the lights? This might do as a replacement.

 

[assegayer]

No you need a proper constant current LED supply, AC will quickly do the LEDs in, a standard 12v lighting transformer will not work. What brand/model are the lights? This might do as a replacement.

Okay just for my own info is so for all LEDs they require constant current trannies. I am sorry i am not to familiar with LEDS. And a small job has turned big. Thanks for the link

 

[freddo]

To run an LED directly requires a current limited supply or the LED will draw enough current that it will destroy itself. There are some LEDs that can be run from a standard (usually 12V DC) power supply, these will have the current limiting built into the light fitting, usually in the form of one or more series resistors. The fixed voltage setup is usually only used with low power LEDs such as those found on LED strips. There is some information here and here.

 

[assegayer]

To run an LED directly requires a current limited supply or the LED will draw enough current that it will destroy itself. There are some LEDs that can be run from a standard (usually 12V DC) power supply, these will have the current limiting built into the light fitting, usually in the form of one or more series resistors. The fixed voltage setup is usually only used with low power LEDs such as those found on LED strips. There is some information here and here.

How would you know how many mA the transformer should be rated at?

 

[freddo]

The same as the old one?!

 

[Silly Sausage]

Just strip them all out, fit GU10 lampholders and 230V LEDs.
12V lighting is a waste of time and effort, as is clearly shown by this thread.

 

[assegayer]

What i meant was if your installing from new how would you know how many mA it needs.. anyway i am ringing every electrical wholesaler and there all saying they dont have that type (250mA). Is there any alternative other then replacing them. Like is there no other driver that would work??!

 

[assegayer]

I would order online as last resort but they want it done quick

 

[Barry White]

Just strip them all out, fit GU10 lampholders and 230V LEDs.
12V lighting is a waste of time and effort, as is clearly shown by this thread.

Totally agree with above but it may not run well with a customer who has only "3 bulbs flickering"
The problem is you match the drivers to the leds then someone fits a different wattage or if shared drivers some fail. Then someone fits a halogen "well it fits"
That said I run leds 12v mr16 on the standard wirewound ac transformers 12v in my kitchen and bathroom for a few years recently replacing them with gu10s.

You may be better ordering online as gu10 is common practice now too many pitfalls with unmatched lights and drivers.

What type of lamp is fitted?