Flickering lights

[Common Sense]

We have this problem we Lights on Dimmers starting to Flicker when we turn them down on a certain time of the day, Always on the same time. The light circuits are on three other breakers all on Phase b there are 2 dimmer switch's and 2 lamps with dimmer plug into outlets I had a fluke voltage recorder on that phase for 12 hours did not see anything weird going on

 

[mopowr steve]

Are they LED lamps on dimmers?
Some don't bode well with dimmers in certain numbers. Add one or change brands can make the difference.

 

[Common Sense]

Are they LED lamps on dimmers?
Some don't bode well with dimmers in certain numbers. Add one or change brands can make the difference.

No Leds

 

[gar]

151197-0851 EST

Common Sense:

Too much missing information in your question.

Pick one circuit that is on a wall dimmer. Call it circuit A. Connect an extension cord to circuit A near the main panel. Plug a 25 W incandescent bulb into the end of the extension cord. Connect another 25 W bulb into the output side of the circuit A dimmer. Put both bulbs side by side. Connect a Fluke DVM with a fast min-max capability to the dimmer output. Set the dimmer to a dimming position where you can expect to have flicker occur.

Define what you mean by flicker. Is flicker a single-shot occurance? If repetitive what is the repetition rate, and the overall duration of flickering? Note that a trained eye can see flicker from a 1 V change in voltage to an incandescent bulb. Also you may need to use a piece or pieces of paper to reduce the bulb brightness.

Simultaneously watch both bulbs during the time when you expect flicker to occur. Also reset the Fluke min-max shortly before you expect flicker. Do both bulbs flicker simultaneously?

If only the bulb on the dimmer output flickers, then one can probably assume that the problem derives from the dimmer.

Provide us more information.

.

 

[Common Sense]

151197-0851 EST

Common Sense:

Too much missing information in your question.

Pick one circuit that is on a wall dimmer. Call it circuit A. Connect an extension cord to circuit A near the main panel. Plug a 25 W incandescent bulb into the end of the extension cord. Connect another 25 W bulb into the output side of the circuit A dimmer. Put both bulbs side by side. Connect a Fluke DVM with a fast min-max capability to the dimmer output. Set the dimmer to a dimming position where you can expect to have flicker occur.

Define what you mean by flicker. Is flicker a single-shot occurance? If repetitive what is the repetition rate, and the overall duration of flickering? Note that a trained eye can see flicker from a 1 V change in voltage to an incandescent bulb. Also you may need to use a piece or pieces of paper to reduce the bulb brightness.

Simultaneously watch both bulbs during the time when you expect flicker to occur. Also reset the Fluke min-max shortly before you expect flicker. Do both bulbs flicker simultaneously?

If only the bulb on the dimmer output flickers, then one can probably assume that the problem derives from the dimmer.

Provide us more information.

.

by flickering I mean turn the dimmer down to a certain level it will blick till you turn it back up again

 

[gar]

151107-1035 EST

Does it blink once? What is the duration of one blink? If it repetitively blinks, then how many blinks per second, and the duration of each blink? Is a blink just a small change in intensity, or does it go to zero and back? Do my two light bulb ex[eriment.

.

 

[growler]

We have this problem we Lights on Dimmers starting to Flicker when we turn them down on a certain time of the day, Always on the same time. The light circuits are on three other breakers all on Phase b there are 2 dimmer switch's and 2 lamps with dimmer plug into outlets I had a fluke voltage recorder on that phase for 12 hours did not see anything weird going on

No Leds

Are you saying that the lights only flicker when the dimmers are turned down at certain times of the day and at other times they work correctly ( no flickering ) ?

I will assume that this is some sort of business, so what type of work is going on?

 

[Common Sense]

Are you saying that the lights only flicker when the dimmers are turned down at certain times of the day and at other times they work correctly ( no flickering ) ?

I will assume that this is some sort of business, so what type of work is going on?

yes that what I mean

that work must be happening every day for the last month at exactly the same time
I doubt it

 

[Common Sense]

151107-1035 EST

Does it blink once? What is the duration of one blink? If it repetitively blinks, then how many blinks per second, and the duration of each blink? Is a blink just a small change in intensity, or does it go to zero and back? Do my two light bulb ex[eriment.

.

no it blinks all the time when the dimmer is turn down
duration of the blink 3 to 4 times a second
goes to 0 and back
just for the record there are 2 wall dimmer both on separate breakers
and 2 floor lamps with dimmer plug into outlets
all on the same phase at the panel

 

[gar]

151107-1261 EST

Common Sense:

If there is no major variation in the AC voltage to the dimmer that correlates to the flickering, then the problem is with the dimmer. There possibly is high frequency interferencre on the AC input to the dimmer that causes the dimmer turn off for each pulse.

We really need to know what the input AC waveform looks like when flickering occurrs. If the AC is clean, then there is the possibility of high power radio frequency interference.

My double light bulb test is a relatively simple type of experiment.

.

 

[Common Sense]

151107-1261 EST

Common Sense:

If there is no major variation in the AC voltage to the dimmer that correlates to the flickering, then the problem is with the dimmer. There possibly is high frequency interferencre on the AC input to the dimmer that causes the dimmer turn off for each pulse.

We really need to know what the input AC waveform looks like when flickering occurrs. If the AC is clean, then there is the possibility of high power radio frequency interference.

My double light bulb test is a relatively simple type of experiment.

.

I will try it next week

 

[Common Sense]

151107-1261 EST

Common Sense:

If there is no major variation in the AC voltage to the dimmer that correlates to the flickering, then the problem is with the dimmer. There possibly is high frequency interferencre on the AC input to the dimmer that causes the dimmer turn off for each pulse.

We really need to know what the input AC waveform looks like when flickering occurrs. If the AC is clean, then there is the possibility of high power radio frequency interference.

My double light bulb test is a relatively simple type of experiment.

.

here is what the graph looks like

 

[Common Sense]

I will try it next week

I move the floor lamp to a different outlet that is on a different phase didn't blink once

 

[gar]

151109-2356 EST

Common Sense:

Your down spikes in voltage are likely motor starting, or transformer inrush, or some other transient high current load. Unless there is oscillation within the spikes, then these would not account for your flicker. The recording instrument response time may not be fast enough to see your 3 to 4 Hz flicker.

For comparison see some of my plots of line voltage and short time average power vs time. Visit http://beta-a2.com/EE-photos.html . My time resolution is 1 second. This means an averaging time of 1 second.

P27 --- The power spikes are not noticeable in the voltage waveform. I had a pretty stiff source to the main panel. The power spikes are from motors starting and their peak values are lower than the real peak because of the 1 second averaging of the power instrument (a TED 1000).

P29 --- Measurement at the outlet to a freezer. This circuit consisted of about 85 ft of #6 to a subpanel, 40 ft of #12 to an outlet, and 12 ft to an outlet strip ( the measurement point ). Only the freezer was monitored. The large voltage spikes are from the circuit impedance. These voltage spikes are very small back at the main panel. The spikes have no pulsed oscillation.


Can you measure two voltages simultaneously with your Fluke recorder? If so then record the input and output voltages of one of the problem dimmers when the flicker occurs, and with a time resolution of 16 milliseconds synchronized with the line if possible.

.

​

 

[Common Sense]

151109-2356 EST

Common Sense:

Your down spikes in voltage are likely motor starting, or transformer inrush, or some other transient high current load. Unless there is oscillation within the spikes, then these would not account for your flicker. The recording instrument response time may not be fast enough to see your 3 to 4 Hz flicker.

For comparison see some of my plots of line voltage and short time average power vs time. Visit http://beta-a2.com/EE-photos.html . My time resolution is 1 second. This means an averaging time of 1 second.

P27 --- The power spikes are not noticeable in the voltage waveform. I had a pretty stiff source to the main panel. The power spikes are from motors starting and their peak values are lower than the real peak because of the 1 second averaging of the power instrument (a TED 1000).

P29 --- Measurement at the outlet to a freezer. This circuit consisted of about 85 ft of #6 to a subpanel, 40 ft of #12 to an outlet, and 12 ft to an outlet strip ( the measurement point ). Only the freezer was monitored. The large voltage spikes are from the circuit impedance. These voltage spikes are very small back at the main panel. The spikes have no pulsed oscillation.


Can you measure two voltages simultaneously with your Fluke recorder? If so then record the input and output voltages of one of the problem dimmers when the flicker occurs, and with a time resolution of 16 milliseconds synchronized with the line if possible.

.

​

I can only measure 1 Voltage input

 

[gar]

151110-23`58 EST

Your problem has some degree of predictability, and repetitiveness so work with your one voltage channel if its response time is fast enough.

Record voltage input to the dimmer, at the dimmer, for an adequate time period to encompass a number of flash cycles. Then do the same at the dimmer output. Although you do not have simultaneous measurements there should be enough pattern information, or lack of, to judge if voltage variations at the input to the dimmer are the cause of the problem.

Provide some pictures.

.