LED mr16

[normspanners]

A quick question for any elecky's
in my kitchen I have two sets of 3 eyeball mr16, each set of 3x 20w has its own tranny in the roof space and a little difficult to get to, they where hal's but I got fed up with bulbs going every week, and replacing burnt connectors and with it being a wooden planked ceiling I was a little concerned re a fire hazard, now if the bulbs went down to two, the lights still worked, but if it dropped to one bulb they stopped working they would come on but stop a few minutes later (I have no idea why the font has done this BTW) now when I fitted the3x4W led's they started a VERY slight flinker a bit like a mains flicker but slower.
if I fit one hal back in to each system they are perfect.
Now my question is it worth getting a equivalent resistor across the bulb line just to stop the flicker? or would that be just as big a fire hazard?
Thanks N

 

[madkayaker]

The mr16 led lamps I have seen have flickered due to the effect of dc conversion from ac. A risitor will get hot weather that will be a fire risk I'm unsure

 

[normspanners]

Thanks MK but I'm pretty sure the trannies are the (heavy type- true transformer) AC only ones, thats why I am using ac-dc mr16 (font back to normal now BTW??) and they are perfect when loaded with one Hal in each??
Maybe I should go for Switch mode??
Seems a shame to have to rip em out when they work-(ish).

 

[madkayaker]

the transformer will be outputting AC but the lamp will be converting to DC probity not that smooth which is why there is a flicker. a proper LED driving transformer will fix the problem

 

[normspanners]

Thanks again MK
Ah just had a thought could the trannies be 'system' voltage regulating IE with 3x 20W hals in the circuit the voltage is pulled down to 12ish and if two bulbs blow the voltage runs high and the safety circuit shuts down the output, so with 3x 4W ish (total 12W only) leds in circuit the voltage is too high for the led bulb circuitry, I will have to check V's.
They are absolutely perfect at the moment with one hal in.

 

[madkayaker]

Could be. I would swap the transformer for led driver

 

[normspanners]

Ok Bud thanks it just a bit of a job getting in the roof space as it is an apex roof with the planking up part of apex then flattening across ten foot up, abit like an upside down boat, leaving avery small space above (about 2ft) Also it is 30ft long and I have to get in through the end.

 

[madkayaker]

I see you could try a resistor and see how hot it gets or try a capacitor across output to smooth it up a bit

 

[madkayaker]

It's possible that's what the halogen is doing with the inductance within the lamp

 

[shenion]

Are the lights on a dimmer?

 

[brightspark]

your better off changing the bulbs to 240v led rather than keeping the 12volt and a so called led driver transformer is just a 12 volt dc regulated power supply transformer , unregulated transformers can go up to 16 or 17 volts and wont do the bulbs any favours and will flicker and do funny things

 

[MattF]

If you want DC output, fit full wave rectifiers to the transformer outputs. The LED units are acting as half wave rectifiers. Regarding transformer versus switch mode, TX every time, IMHO. Switch modes are a steaming pile of turd. They're functional, but have no where near the longevity of transformers.

 

[normspanners]

Thanks Guys

Are the lights on a dimmer?

No dimmer

your better off changing the bulbs to 240v led rather than keeping the 12volt and a so called led driver transformer is just a 12 volt dc regulated power supply transformer , unregulated transformers can go up to 16 or 17 volts and wont do the bulbs any favours and will flicker and do funny things

As quoted there is very little roof space in the kitchen, it is planks nailed to the rafters with insulation and visqueen sheeting between so to change the wiring will be a pain. The voltage going to 16ish volts is exactly my thoughts but I have had one led in each for months now and they have been fine, MUCH better light to work by and have lasted. I was concerned regards the fire aspect with the hal's having changed 2-3 m16 burnt connectors and tails.

If you want DC output, fit full wave rectifiers to the transformer outputs.

I had thought about that but because I am on overheads the volts are up n down like ayo-yo my incoming is at about 243v ish normally, so if the output is say 14v-16v or more OC fitting a FWBR I could be well at 18-20v DC and I am back to overrunning the bulbs ?

 

[Wedg1e]

Switch modes are a steaming pile of turd. They're functional, but have no where near the longevity of transformers.

That they may be, but there's a mountain of cast-off computer PSUs around now that will give you 12V (and 5V) at bazillions of Amps that would be more than enough to run every LED in the country Built-in mains socket and cooling fan and they're used to running for 24 hours a day in warm offices.
Usually just need to link a couple of wires together to get them to start-up (simulates pressing the On switch on the PC)...

 

[MattF]

That they may be, but there's a mountain of cast-off computer PSUs around now....

That's a fair point. They're definitely cheap.

 

[normspanners]

That is a good idea I would do away with the fan though as it is only 40 W total power as opposed to 200W ish for the hals