mr16 led bulb flashes on and off when warm?

[retrofitblues]

Hi, I have just replaced 5 x halogen mr16 bulbs with 5 x 4w led mr16. I changed the transformer to a 2a led driver. 4 of the bulbs work fine but one keeps slowly flashing on and off after about 15minutes of being switched on. Ive tried changing the bulb but had same problem with new bulb. Is there any obvious reason why it would do this? I checked the voltage and its at 11.97 volts. Is it just faulty bulbs or is it the driver causing this? And light on this would be appriciated.

[panicmechanic]

I'm not an electrician, but I guess the MR16s come with their own drivers. These are typically made to run on 12 V unregulated AC current from a halogen transformer. Connecting them to an external led driver may bring trouble and might destroy either internal or external driver.
The solution would be to find a smaller halogen transformer, or to connect more MR16 led bulbs to the old transformer, bringing it closer to it's designed load.

[Lynx_Arc]

It is either a socket or the power supply. In some rare cases when metal parts heat up they can expand and that changes the electrical contacts. This could possibly cause the power to go off till it cools down and the metal contracts to make contact again.

[retrofitblues]

I'm not an electrician, but I guess the MR16s come with their own drivers. These are typically made to run on 12 V unregulated AC current from a halogen transformer. Connecting them to an external led driver may bring trouble and might destroy either internal or external driver.
The solution would be to find a smaller halogen transformer, or to connect more MR16 led bulbs to the old transformer, bringing it closer to it's designed load.

It's on a cable track light system so there are 5 fittings on it which at 4w a bulb makes a total of 20w, be hard to add enough bulbs to make it up to the 150w the old transformer needed. The led driver is 12v dc 2A so 25w max and is suppose to be more stable with these bulbs. But i'm new to this technology.

It is either a socket or the power supply. In some rare cases when metal parts heat up they can expand and that changes the electrical contacts. This could possibly cause the power to go off till it cools down and the metal contracts to make contact again.

This sounds more likely, I bought 18 bulbs in total and after swapping them all around ive found it is happening to 6 of them, the other 12 seem to work perfectly. So i think it must be faulty bulbs. It does seem an odd fault though as they work perfectly fine for 15-20 minutes and then they start to flash very slowly (they stay on for 3seconds then off for half a second then back on for 3 seconds...etc). But that would be in line with them getting hot and expanding i guess.

Thanks for responding....i think i'll dismantle one and see if I can see anything obvious inside.

[DM51]

This belongs in Fixed Lighting. Moving it now...

[purduephotog]

It's on a cable track light system so there are 5 fittings on it which at 4w a bulb makes a total of 20w, be hard to add enough bulbs to make it up to the 150w the old transformer needed. The led driver is 12v dc 2A so 25w max and is suppose to be more stable with these bulbs. But i'm new to this technology.



This sounds more likely, I bought 18 bulbs in total and after swapping them all around ive found it is happening to 6 of them, the other 12 seem to work perfectly. So i think it must be faulty bulbs. It does seem an odd fault though as they work perfectly fine for 15-20 minutes and then they start to flash very slowly (they stay on for 3seconds then off for half a second then back on for 3 seconds...etc). But that would be in line with them getting hot and expanding i guess.

Thanks for responding....i think i'll dismantle one and see if I can see anything obvious inside.

THat sounds like an overheat condition on the driver. IF (I stress if) it were a VIPR222a driver, that is what happens- heats up to 100C, shuts down, comes back on as soon as it cools off.

[Lynx_Arc]

THat sounds like an overheat condition on the driver. IF (I stress if) it were a VIPR222a driver, that is what happens- heats up to 100C, shuts down, comes back on as soon as it cools off.

one way of testing for overheat would be to get a can of compressed air and spray the driver with freon when it shuts down and see if it runs again if the shut off time is long enough to guage.

[purduephotog]

one way of testing for overheat would be to get a can of compressed air and spray the driver with freon when it shuts down and see if it runs again if the shut off time is long enough to guage.

Or.... just put the lights in the freezer and run them that way. If it takes longer to overheat/andor doesn't... well...