Need Help: House Lighting not Dimmable

[ChurchLightingNewb]

@ChurchLightingNewb Two points:
1; Welcome; I'm glad to learn you're not a 'once & done' / 'one hit wonder'.
2; Have you tried a dummy load???
Toodleoo!
Ron Hebbard

Well, starting from the top I tested the lights in house. Previously I had a couple other people do it for me and told me they are dimmable. Turns out that they are partially dimmable. I bought a replacement at Home Depot and seems to be a good fix. about to go and buy the whole set and see if it all works out. I really hope soo. So to everyone that suggested I recheck to make sure my lights are fully dimmable. Thank you.

 

[microstar]

Well, starting from the top I tested the lights in house. Previously I had a couple other people do it for me and told me they are dimmable. Turns out that they are partially dimmable. I bought a replacement at Home Depot and seems to be a good fix. about to go and buy the whole set and see if it all works out. I really hope soo. So to everyone that suggested I recheck to make sure my lights are fully dimmable. Thank you.

From prior experience, I suggest buying only enough replacement lamps to outfit only the number on one dimmer channel. This will show you any compatibility problems before you bet on the whole installation.

 

[Malabaristo]

Well, starting from the top I tested the lights in house. Previously I had a couple other people do it for me and told me they are dimmable. Turns out that they are partially dimmable. I bought a replacement at Home Depot and seems to be a good fix. about to go and buy the whole set and see if it all works out. I really hope soo. So to everyone that suggested I recheck to make sure my lights are fully dimmable. Thank you.

If you tested one lamp either by itself or mixed in with a different type of lamp on the same circuit, then you did not test that lamp. Many of the dimming problems with LEDs will change depending on the number of lamps on a circuit and mixing different lamp types on the same circuit can have unpredictable effects that could be better or worse than what you'll get with a uniform set. There are some clever things you can do with a small number of lamps (4-6) to make some educated guesses about how a larger number will behave, but that requires an oscilloscope with appropriate probes to monitor the voltage and current while dimming. The best approach for an average person is to figure out which circuit has the most lamps and get enough to replace all of the ones on that circuit before committing to buying enough for the whole room.

 

[microstar]

If you tested one lamp either by itself or mixed in with a different type of lamp on the same circuit, then you did not test that lamp. Many of the dimming problems with LEDs will change depending on the number of lamps on a circuit and mixing different lamp types on the same circuit can have unpredictable effects that could be better or worse than what you'll get with a uniform set. There are some clever things you can do with a small number of lamps (4-6) to make some educated guesses about how a larger number will behave, but that requires an oscilloscope with appropriate probes to monitor the voltage and current while dimming. The best approach for an average person is to figure out which circuit has the most lamps and get enough to replace all of the ones on that circuit before committing to buying enough for the whole room.

Would not figuring out which circuit had the LEAST lamps and replacing those and then testing dimming action be a better bet? While we know the interaction between lamp(s) and dimmer are complex, I've had more problems getting good dimming on lightly loaded dimmers. Sometimes circuits have to be combined to get enough load for things to go well because I would rather not deal with a ghost load.

 

[RonHebbard]

If you tested one lamp either by itself or mixed in with a different type of lamp on the same circuit, then you did not test that lamp. Many of the dimming problems with LEDs will change depending on the number of lamps on a circuit and mixing different lamp types on the same circuit can have unpredictable effects that could be better or worse than what you'll get with a uniform set. There are some clever things you can do with a small number of lamps (4-6) to make some educated guesses about how a larger number will behave, but that requires an oscilloscope with appropriate probes to monitor the voltage and current while dimming. The best approach for an average person is to figure out which circuit has the most lamps and get enough to replace all of the ones on that circuit before committing to buying enough for the whole room.

@ChurchLightingNewb If (for example / slash instance) you had one, or more, standard incandescent lamps on the same dimmer, you're neither seeing nor testing how the LED lamp(s) behave on one of your dimmers without an incandescent load, 'dummy load' or otherwise.
Toodleoo!
Ron Hebbard

 

[Malabaristo]

Would not figuring out which circuit had the LEAST lamps and replacing those and then testing dimming action be a better bet? While we know the interaction between lamp(s) and dimmer are complex, I've had more problems getting good dimming on lightly loaded dimmers. Sometimes circuits have to be combined to get enough load for things to go well because I would rather not deal with a ghost load.

Well, if you get enough to test the most, then you can also test the least just by removing the appropriate number

There are three main issues that potentially get worse as you add more lamps on a circuit: capacitive effects, initial inrush, and repetitive peak currents. Capacitive effects are mostly an issue with SCR or TRIAC dimmers because those need voltage and current to go to zero at about the same time every half-cycle. Capacitive loads mess this up by creating a phase shift between voltage and current. Some dimmers allow you to adjust this "window" of time to mitigate the issue, but very capacitive loads may just not be fixable without affecting other aspects of dimming. The behavior you see when this happens is usually an occasional or frequent flash-to-full from a dimmed level but sometimes it's bad enough that the dimmer acts like a non-dim. Sometimes you can fix this by adding a dummy load (because it makes the overall circuit more resistive), but swapping to a different type of dimmer is always a better solution when possible.

Inrush and repetitive peak currents are mostly an issue for ELV-type dimmers (reverse-phase or phase-adaptive) since they generally aren't as robust as SCR dimmers. These problems don't necessarily cause any dimming performance issues, but they can damage the dimmer and may even cause premature failure of the LEDs. One extreme case I saw of the latter actually was on an SCR dimmer: there were a couple of large chandeliers with something like 120 lamps on a single 100A dimmer (retrofit from incandescent lamps). In that case the owners were happy with the dimming performance and the dimmers were handling the load just fine, but they asked for help figuring out why they were seeing a lot of very premature LED failures. What I found was a combination of repetitive peak currents in the lamps interacting with the big inductor in the dimmer resulting in voltage spikes of up to 480-500 Vp on a 120 VAC circuit. That was surprising to say the least... but at least it clearly explained the failures.

There are also times where repetitive peak currents can more directly impact dimming performance with any type of dimmer, but that interaction is kind of difficult to describe without more background information than I feel motivated to write at the moment. Suffice it to say that yes, too many can be just as bad or worse than two few when it comes to dimming LEDs.

 

[RonHebbard]

Well, if you get enough to test the most, then you can also test the least just by removing the appropriate number

There are three main issues that potentially get worse as you add more lamps on a circuit: capacitive effects, initial inrush, and repetitive peak currents. Capacitive effects are mostly an issue with SCR or TRIAC dimmers because those need voltage and current to go to zero at about the same time every half-cycle. Capacitive loads mess this up by creating a phase shift between voltage and current. Some dimmers allow you to adjust this "window" of time to mitigate the issue, but very capacitive loads may just not be fixable without affecting other aspects of dimming. The behavior you see when this happens is usually an occasional or frequent flash-to-full from a dimmed level but sometimes it's bad enough that the dimmer acts like a non-dim. Sometimes you can fix this by adding a dummy load (because it makes the overall circuit more resistive), but swapping to a different type of dimmer is always a better solution when possible.

Inrush and repetitive peak currents are mostly an issue for ELV-type dimmers (reverse-phase or phase-adaptive) since they generally aren't as robust as SCR dimmers. These problems don't necessarily cause any dimming performance issues, but they can damage the dimmer and may even cause premature failure of the LEDs. One extreme case I saw of the latter actually was on an SCR dimmer: there were a couple of large chandeliers with something like 120 lamps on a single 100A dimmer (retrofit from incandescent lamps). In that case the owners were happy with the dimming performance and the dimmers were handling the load just fine, but they asked for help figuring out why they were seeing a lot of very premature LED failures. What I found was a combination of repetitive peak currents in the lamps interacting with the big inductor in the dimmer resulting in voltage spikes of up to 480-500 Vp on a 120 VAC circuit. That was surprising to say the least... but at least it clearly explained the failures.

There are also times where repetitive peak currents can more directly impact dimming performance with any type of dimmer, but that interaction is kind of difficult to describe without more background information than I feel motivated to write at the moment. Suffice it to say that yes, too many can be just as bad or worse than two few when it comes to dimming LEDs.

@Malabaristo Let me guess: Wisconsin; are you employed by ETC?
Think POSITIVE!
Toodleoo!
Ron Hebbard

 

[Malabaristo]

@Malabaristo Let me guess: Wisconsin; are you employed by ETC?

Hey now! While they may have a monopoly on the theatre market, they don't have a complete monopoly on people who know stuff in the Madison area

My main job is centered around high school theatre, but I do have a variety of other experiences to pull from. I tend not to include too many resume details in settings like this--mostly just for the sake of not having to worry about whether I'm being perceived as representing my employer(s) when I post.