Flashing LED Luminaire

Midwest · Feb 8, 2019

In the premises I now work, there has been an LED Luminaire that has never worked (apparently) since the place was opened two years ago.

The light is as below, which is described as dimmable. After taking the fitting down (no mean feat), I found the below dimmer which appeared damaged. So I ordered a exact replacement. The luminaire flex was originally connected up to output 2 (output 1 was physically damaged). The driver casing instructions, say output 1 must be used before output 2, which is how I've connected it. However when operated (via dimmer switch) of other dissimilar lights, it doesn't like it & flashes.

I do not know if the dimmer switch is compatible (don't know make etc), there is another similar luminaire, which works (and dims) with other (LED) lighting and similar dimmer.

I'll have to take it down again and try it on the bench. When I've found the below driver wiring instructions, it shows some 'DIM' (pulse) terminals, but only 0-10V, which I'm thinking must be the connections to use, but I have no idea what voltage the LED lamp uses. Don't want to make an expensive mistake.

Accessing the working one, will require scaffolding so can't inspect that easily. So can anyone advise me?

Shoei · Feb 8, 2019

Sounds like the driver may not be compatible with the lamp, that driver is for 'bare' LEDs but it would be unusual for a pendant light to have an 'LED only' lamp, more likely to be 12V or mains.

What's in the dimmer switch of the working one? That driver would use a 100k/log potentiometer, if the working one has a mains dimmer then it would suggest the wrong driver has been fitted to the flashing one. If the dimmers are both 100k potentiometers, then it sounds like a wrong or faulty lamp in the pendant.

Midwest · Feb 8, 2019

The lamp is a sealed LED type. I did find a set of instructions online, can't find it now, that showed a similar driver with the lamp etc. I have my doubts, whether the thing has ever worked, and left deliberately by the contractor.

The luminaire is in a spa area, thats open early to late, so its difficult to access without ruining peoples visits, and I don't get paid enough to work late!

I might just have to alter the luminaire accordingly, to work with some sort of 230V dimmable glob lamp; but for its retail value at £600 it would be nice to getting the thing working as its been designed.

AJshep · Feb 8, 2019

Sounds like maybe the wrong driver.
The specs state its PWM but the intructions for the light state trailing edge/ reverse phase is prefered.
Sounds like the wiring is correct and that at the dimmer you have a pair from the 0-10v terminals of the driver..
Maybe the lamp/fitting doesnt like PWM dimming alot of LED lamps don't.

Pulse Width Modulation (PWM) PWM is based on a simple principle: if the power supply of a lamp is interrupted at regular intervals, the average lighting output will decrease. In other words, PWM makes lamps flicker in order to reduce luminous output. Of course, the flickering has to occur fast enough for it to be unperceivable by the human eye. This dimming method is better suited for lighting technologies such as incandescent bulbs, which have a slow response. PWM is feasible with LED lighting, but the interruptions must be much faster give the response speed of LEDs.

Wilko · Feb 8, 2019

Hi - that supply wouldn't work on a normal dimmer, I reckon. It's looking for a 100k pot. to vary the output, according to the instructions. I will temper that with the observation that its Friday night and I have been consuming red.

AJshep · Feb 8, 2019

I agree you need a 0-10v dimmer.
Im still confused as to the light fitting though. Looks like there are two types.
One supplied with a E27 lampholder and one with a fixed LED lamp ( various versions). AS Shoei said it seems strange to have a pendant type fitting that would only take a low voltage stand alone lamp.

As you have a driver I assume that its the latter. In which case, like mentioned could be the wrong type of dimmer has been used or could be the lamp needs a different method of dimming.
I would start by checking the dimmer is a 0-10v type, then get the specs for the light maybe try a different method of dimming,
This is similar driver to the one posted but it uses trailing edge rather than PWM. Obviously it would need checking if you need constant current or volotage.

LCBI 10 W phase-cut / 1–10 V lp - Tridonic - https://www.tridonic.com/com/en/products/led-converter-lcbi-10w-180-350-500ma-phase-cut-1-10v-lp.asp