Slight light flickering

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AC\DC

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Florence,Oregon,Lane
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EC
Hello, had a customer that had one circuit that flickered randomly, no voltage fluctuation. The flicker was barley noticeable but effected all lights . My first thought was something electronic throwing noise back into the circuit. Unplugged a mini water fridge and it stopped flickering.
my question is , noise being thrown on the circuit by a electronic device would not cause Incandescent to flicker also ,Correct . So it was the compressor cycling that caused it.
I don’t know the proper term for what I am referring to as ”noise” also if you could correct me
 
I had that happen with LED's it needed a constant current or voltage driver. levels out the peaks of the cycle.
 
If the lights are flickering then there has to be some sort of voltage fluctuation.

However LEDs require driver circuits which by their nature would tend to make them insensitive to voltage variations. Unfortunately such driver circuits make the LEDs insensitive to dimming. Most modern LEDs add in detection of dimming waveform to adjust their output, so that the LED is actually dimmable.

It is possible that slight electrical noise or voltage variations that would not be noticed in an incandescent lamp will trigger the dimming detection of the LED lamp, leading to noticeable flicker.

You might see how a non-dimming lamp performs.

Jon
 
I don't think it's anything to worry about. Slight flickering at random times can be normal. Utility switching transients, large loads turning off and on somewhere all can cause it.

-Hal
 
What type of lighting? What controls? And where does the power come from?

I have seen all 3 be the culprits, from cheap LED bulbs, to crap dimmers, to a loose wire that came to the switch outlet via some other location as a wire tie or pass-through.
 
it effects every light on only one circuit. No dimmer, led and incandescent. stopped when cooler was unplugged just wondering if the compressor cycling or noise.
 
AC\DC said:
it effects every light on only one circuit. No dimmer, led and incandescent. stopped when cooler was unplugged just wondering if the compressor cycling or noise.
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Is the cooler on same BC? Does the flicker only happen while the cooler is steady run?

Does the cooler have a "run" cap on it's motor? When a cap fails it usually fails, but maybe that one is intermittently changing it's mfd, which will cause "jumps" in line amps to the cooler motor. Even a failing motor can cause "jumps" in line amps.

Does the cooler have a VFD drive or something??

The culprit seems to be the cooler, the why's and how's are TBD.
 
AC\DC said:
Did not take the cooler apart it was a plug in water cooler so I found the culprit. Then down the road i went.



Thanks I was thinking it was not that since it was effecting the Incandescent also.
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Could still be that if the unit is "flickering" on amps use for some reason.
 
Perhaps the rotor of the induction motor on the fridge compressor has one or more broken bars, and that's causing the 60 Hz current to have low frequency sidebands around it at multiples of the slip frequency (e.g., 3 Hz for 5% slip) as noted on the diagnostic chart below. Components of these sidebands that are in phase with the 60 Hz "carrier" would be from low frequency variations of the current drawn by the motor. If present such current variations might make the branch circuit voltage vary enough to cause lamps to flicker.
... Or maybe the motor is of such low quality that such current variations are inherent in the design even if it hasn't been broken.

 
Might be best to scope the BC lines to see what's there ;)
 
AC\DC said:
Did not take the cooler apart it was a plug in water cooler so I found the culprit. Then down the road i went.



Thanks I was thinking it was not that since it was effecting the Incandescent also.
Click to expand...
Sounds like the perfect end to service call. As much as I would like to know what is happening to the best of my abilities, the customer shouldn’t always have to foot the bill for my education.

I have been known to take items back to the shop for an autopsy, at my expense.
 
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