LED trims just started flickering

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Ponchik

Ponchik

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Electronologist
The LED trims made by Feit have been in place for the last 4 years on Lutron Diva dimmers. In different rooms and different dimmers. Now they decided to flicker when dimmed. I am sure it flickers when on full brightness I just can't see it.

Voltage reading on the breaker is OK 120V, I connect a incandescent bulb and it does not flicker, yet the rest of the LED still flicker with the incandescent still on the circuit, With all of the LEDs ON, the circuit breaker has a slight buzzing noise, confirmed the noise to that breaker with a stethoscope. Installed a new breaker (maybe old one had a bad contact) still flickering. Installed new dimmer (Lutron Diva) still flicker. Checked voltage at the LED trim 103volts.

Even though the chances are very low, but I don't see why all of the trims and dimmers would go bad at the same time. Next step i step is check voltage reading in all of the rooms and see if consistent 103V. 103V is puzzling to me.

Your suggestions please.
 
The can connections twisted in a wire nut or stuck in those push locks?
 
Did you measure the voltage at the dimmer itself when it was turned up all the way? The output of dimmers will not typically go up to the full value of the line input voltage, although 103V is on the low side.
 
Do you have problems if you bypass dimmer (run "unconditioned" line volts directly to luminaires)? As mentioned even dimmers on full brightness setting still potentially have some voltage wave modification on the output.
 
The 103V is probably about what would be expected with a dimmer set to high in the circuit. If you look at the led dimming range testing of most dimmers the high setting is typically around 90% of LED rated output.
 
kwired said:
Do you have problems if you bypass dimmer (run "unconditioned" line volts directly to luminaires)? As mentioned even dimmers on full brightness setting still potentially have some voltage wave modification on the output.
Click to expand...

I did bypass one of the dimmers and it "seemed" to be OK. "seemed" because at full brightness I can't tell much fluctuation.
Then again if there is voltage wave modification past the dimmer, why does it show up now after 4 years of service?

This issue has me scratching my head.
 
synchro said:
Did you measure the voltage at the dimmer itself when it was turned up all the way? The output of dimmers will not typically go up to the full value of the line input voltage, although 103V is on the low side.
Click to expand...

I measured at one of the recessed lights.
 
edward said:
I did bypass one of the dimmers and it "seemed" to be OK. "seemed" because at full brightness I can't tell much fluctuation.
Then again if there is voltage wave modification past the dimmer, why does it show up now after 4 years of service?

This issue has me scratching my head.
Click to expand...
Something has changed and input volts is now lower than it has been? Might not even be something on the premises but rather POCO delivering slightly lower voltage for some reason?

they haven't perfected LED's yet, especially when used with dimmers. Seems most the troubles with them involve ones on dimmers, or not so stable input voltage, and don't take much of a input fluctuation to matter. Other common problems they simply don't work at all vs the dimmer related issues.
 
Next time I go out I will turn off all of the breakers except the circuit in questions and see if it flicker. If not then I will turn loads on one at a time and monitor. Also, try different dimmer type.
 
edward said:
Also, try different dimmer type.
Click to expand...
Most LED makers have a list of compatible dimmers. And, I've found that the listed dimmers usually have electronically-comparable models that have only physical differences, like Togglers vs Decora styles with slides.
 
edward said:
Next time I go out I will turn off all of the breakers except the circuit in questions and see if it flicker. If not then I will turn loads on one at a time and monitor. Also, try different dimmer type.
Click to expand...
Good ideas. It's possible there could be noise from a load on another circuit (like a switching supply, inverter drive, etc.) that is being coupled into the lighting circuit and causing the flickering.

I suggest trying an ELV (aka reverse phase) type dimmer, assuming you now have the more common forward phase type dimmer.
 
LarryFine said:
Most LED makers have a list of compatible dimmers. And, I've found that the listed dimmers usually have electronically-comparable models that have only physical differences, like Togglers vs Decora styles with slides.
Click to expand...
I've run into ones that do have troubles with a "standard" dimmer that is on their list, but do work better with one that is intended to be used with LED's. Note I said better and not that they absolutely work great.
 
edward said:
I am sure it flickers when on full brightness I just can't see it.
>persistence of vision and the incand bulb filament can't change brightness very fast.

the circuit breaker has a slight buzzing noise, confirmed the noise to that breaker with a stethoscope.
>the current through the breaker is not a sine wave, but this may normal for the circuitry that drives LEDs.
Click to expand...
An o-scope might give you clues but there may be more info in the current waveforms.
The LED driver should work, or they used to work, as an AC-voltage voltage-source to a direct current constant-current-source convertor.

It never occurred to me to use a stethoscope on a breaker, but for sure on car suspension noises, etc.. Low tech, but it works.
 
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kwired said:
I've run into ones that do have troubles with a "standard" dimmer that is on their list, but do work better with one that is intended to be used with LED's. Note I said better and not that they absolutely work great.
Click to expand...

The existing dimmers are rated for LED.

I am going back to the job in about a month. I will do detailed testing and see if I can see what the issue is.

I will report back with what I find, if anything.
 
So the breaker acts like a mini loudspeaker, a transducer that converts current to sound, and works better with non-sinusoid current waveforms.
And nowadays probably most current waveforms are not sine waves.
 
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