[DesertRatTom]

:help: Been doing a project at the church where my Sr. group meets. Installed theatrical lights using LED bulbs. Two circuits with an LED type dimmer and very light loads on each. 28 watts on one, 42 on the other. Dimmers rated for 600 watts incandescent, 150 LED.

When faded down fully, the lights still glow visibly.

What is the best way to get the dimmer to go to full blackout? They are leviton brand dimmers. Tried using a couple of 40 watt lights as a dummy load, but the lights are still on when I dim all the way to the bottom of the slider.

I guess I could put some high wattage lights on the circuit, but that would be ineligant and hot. Any other suggestions from you electricians out there?

 

[DesertRatTom]

Put a switch in line to kill the whole circuit?
Herb

Got a switch on the dimmer that kills it, but I want it to fade to black. Got the houselights (LED track lights) to go to black and I want a nice cross fade for the shows.

 

[DesertRatTom]

I am sure it is the bulb that converts the power down to DC. With a DC circuit, resistance is all that's required to reduce voltage. At 14 watts, it doesn't take much capacity to cut the voltage. Seems there is a point at which the reduced voltage reaches a point where some bulbs begin to flicker, so the dimmers are designed not to go down to zero and continuously leak about 10 percent of the total power. I ordered some commercial resistor devices that promise to prevent the flickering, probably by automatically cutting off all power at the flicker point. Hopefully that will solve the problem.

Otherwise, it seems there are two ways to handle this: 1) learn to slide the dimmers down and click the off switch at that point, or 2) replace the bulbs with incandescent models, which filaments stop glowing at a certain point.

Unless, of course, someone here has a solution.

 

[DesertRatTom]

Thanks Charles. I tried a larger load on the dimmers and it actually raised the low-light level when the slider was all the way down! I think dimming down to black isn't going to happen, and that I will either have to switch to incandescent bulbs or just live with it by shutting off the light with the rocker switch when the dimmer slider hits bottom. I may have to replace the dimmers if I go to incandescents, but I will be able to fade to black. I have a couple of gadgets coming to try, but I think they are nothing more than what I tried with the bulb experiment today. If they don't work I'll send them back to Amazon and use the refund to get the incandescent bulbs, which might also be a tad brighter.

 

[DesertRatTom]

Thanks Ulrich for the suggestion. What amazes me is that the wireless dimmer I installed dims all 30 of the LED track lights completely to black. Maybe I should contact CREE, the company that makes the lights, to find out whether they have any suggestion, maybe a different dimmer brand.

 

[DesertRatTom]

I went on CREE's site and found a number of data sheets. The bulbs will dim down to 5%, which isn't bad, but I have the wrong dimmer. They list compatible dimmers, so maybe I'll give it one more try and run a test with a recommended dimmer.

Hope this is a useful string for someone else. Lots of ins and outs for anyone considering dimmed LED lighting.

 

[DesertRatTom]

SOLUTION OK, got a reply that helped, then realized that the instructions were two sided and there seems to be a programmable minimum voltage that has to be programmed. Haven't been able to do that yet, but I think that will help. The bulbs are able to dim down to 5 percent, but the dimmer is preset much higher. Once programmed (which involves a tiny switch between CFL and LED), then set the minimum light level, then switch back to LED.

The instructions were there (in tiny print) all the time, but I didn't notice and presumed they were in another language. Duhhh. I'll probably try that tomorrow afternoon and let you guys know. The dimmer is a Leviton Decora, fyi.

One more electronic gadget to go and we'll be state of the art for AV at The Venue. Hopefully I can get the platform extended tomorrow too, but I'm going to need a helper to move the heavy sheet goods.

 

[DesertRatTom]

Not knowing all the specs involved in the question, I know for 120 volt incandescent lighting there are dimmers that slide all the way down to off. You can actually feel the detent as the lever enters the off position. To turn it on you just slide it up through the detent and it starts brightening up. I would imagine by now, that there are led labeled dimmers that do the same. If I’m not understanding the question correctly, I apologize.

That's kind of what I was looking for, but the problem is that there is a minimum level of brightness (voltage, really) below which an LED bulb will begin flickering. So LED dimmers go down to that level, but not necessarily all the way off. Taking the light down to that minimum level is the point of the adjustment I mentioned in my last post. I will be experimenting with that adjustment most likely this weekend and will see what happens. The dimmers in my house (it's all LED now) do go all the way to off, but they are not suitable for theater style light dimming (hard to get a grip on them), so I have some hopes the ones at the church will go down to zero, but we shall see this weekend.

For us fixer upper types, LED installation is going to become a common task, so I want to get to the solution since several members have mentioned having the same problem. Might even do a separate post with pictures and drawings.

 

[DesertRatTom]

Artie, Good suggestions. CREE has been very helpful so far. What amazes me is how difficult it was to get the basic information I really needed. In fact, what I've put together so far has not appeared anywhere in one place. I put it together only after a lot of fiddling and thinking and searching. With LEDs taking over the world, this kind of information needs to be clearly spelled out. And dimmers should be able to be preset to the lowest possible light level, then go to black, and more importantly, should have that feature prominently displayed on the packaging.