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blinking led retro trims and led bulbs throughout the house.

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Mark Toler

Member
Location
Mesquite Tx.
Occupation
Electrical contractor
Still Blinking Led trims, bulbs. We wired a 2000 Sq.Ft. barn dominium. There was not a uffer installed prior to concrete. The house now has three ground rods 6Ft apart. We have changed out all the recess trims and bulbs, checked all switches and outlets for connection problems none found. Changed out the main and guts at the 200A panel, all grounds and neutrals are good, power company has ran a test to check there transformer it checks out good. We ran the house off of a generator totally off the grid, still blinked. The blinking will jump to other lighting circuits. I put a meter that test magnetic field on the Island. It would spike max about every 10 minutes. My next move is to unplug all devices from any lighting circuit. Remove the dust zapping electronic air cleaner.
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
Still Blinking Led trims, bulbs. We wired a 2000 Sq.Ft. barn dominium. There was not a uffer installed prior to concrete. The house now has three ground rods 6Ft apart. We have changed out all the recess trims and bulbs, checked all switches and outlets for connection problems none found. Changed out the main and guts at the 200A panel, all grounds and neutrals are good, power company has ran a test to check there transformer it checks out good. We ran the house off of a generator totally off the grid, still blinked. The blinking will jump to other lighting circuits. I put a meter that test magnetic field on the Island. It would spike max about every 10 minutes. My next move is to unplug all devices from any lighting circuit. Remove the dust zapping electronic air cleaner.
You gave us no voltage measurements. No current. Ground rods or ufer mean nothing to the problem.
Brand name fixtures?
How does it jump to other circuits? Have you installed some incandescent lamps for testing purposes?
What type of meter for magnetic fields? Scale?
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
There was a recent thread I wrote where I was having problems with some Patriot brand lighting. Not sure if a service lateral of around 500 feet had anything to do with it.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
210420-2235 EDT

Mark Toler:

Take one of the blinking lights to your home plug into a circuit with no dimmer feeding the light under test. Does it blink? Next connect to a Variac and adjust input voltage. Can you get it to blink? If you can create blinking, then shunt that LED with a 100 W incandescent bulb. Does this stop the blinking?

If you can create blinking, then buy a CREE 9 W LED bulb and see if when it is connected in parallel with your blinking light there is blinking of the CREE.

If CREE does not blink, and I do not expect it to do so, then take the CREE to the home where you have a problem. At this home is there any place where the CREE blinks when other LEDs are blinking?

.
 

Mark Toler

Member
Location
Mesquite Tx.
Occupation
Electrical contractor
You gave us no voltage measurements. No current. Ground rods or ufer mean nothing to the problem.
Brand name fixtures?
How does it jump to other circuits? Have you installed some incandescent lamps for testing purposes?
What type of meter for magnetic fields? Scale?
The voltage is 124 to neutral and ground. I opened the switch and put a voltage tester on it while the blinking was happening. Voltage did not move steady 124V N to Hot, Switch leg to hot. I put incandescent bulbs on the island pendants home owner said they blinked. Everything we took out has been installed in another house and no problems with the product. Not sure about the magnetic tester we borrowed it for the day. How and why it jumps to other circuits is not understood. Thx for the response.
 

Mark Toler

Member
Location
Mesquite Tx.
Occupation
Electrical contractor
210420-2235 EDT

Mark Toler:

Take one of the blinking lights to your home plug into a circuit with no dimmer feeding the light under test. Does it blink? Next connect to a Variac and adjust input voltage. Can you get it to blink? If you can create blinking, then shunt that LED with a 100 W incandescent bulb. Does this stop the blinking?

If you can create blinking, then buy a CREE 9 W LED bulb and see if when it is connected in parallel with your blinking light there is blinking of the CREE.

If CREE does not blink, and I do not expect it to do so, then take the CREE to the home where you have a problem. At this home is there any place where the CREE blinks when other LEDs are blinking?

.
All the trims and bulbs that were replaced have been put in another home no blinking.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
210421-2118 EDT

Mark Toler and ptonsparky:

From post #7.
I have found that incandescents will flicker on a rather short duration change in voltage, but it really takes about a 2 V change to see flicker, and simultaneously looking at both an incandescent and an LED in parallel I tend to see about a comparable flicker. A CREE bulb was used.

If you see an incandescent flicker, then there is a noticeable change in voltage, but the change in duration can be rather short. Blinking of incandescents at the home in question implies a voltage fluctuation of probably more than 2 V at that home. And therefore would not be an LED bulb problem.

That you tested the LEDs at another location and there was no flicker may be an indication of no LED problem, but this needs to be over a wide range of applied voltage.

From post #9.
A fluke 87 in min-max mode is not real fast at detecting voltage changes. I don't remember what I found relative to this. My Fluke 27 is not fast. The the Fluke 27 does not have a pulse detection mode, the 87 has a peak capture response of 0.25 milliseconds, note this is just peak of the absolute value (full wave rectified), not minimum. The 87 response time is much longer on min-max.

I think you need to study voltage fluctuations at the home in question. A memory scope would be most useful for this.

.
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
I was thinking more in line that two min max meters would catch the voltage difference caused by a compromised neutral, if that were the case. The few blinking LEDs we have come across were easily remedied.
The analog bar graphs on the 87 are pretty quick but would probably just blink with the lights if voltage is the problem.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
210422-2238 EDT

ptonsparky:

Just ran an experiment --- 15 W frosted incandescent at about 120 V, 20 ohm resistor in series shunted with a normally closed contact on a KUP 24 V DC relay. Pulsed the relay using a 25 mfd electrolytic at about 18 V. The capacitor is charged and removed from the power supply, then discharged thru the relay coil. Closure time of the relay about 2 60 Hz cycles. Change in bulb voltage about 2.5 V. Bulb voltage change not detectable with Fluke 27 in min-max mode.

The light change is slightly noticeable, signal known exactly.

I somewhat suggest that a 15 W 120 V incandescent is a better short pulse detector than a Fluke.

In the past when I compared a CREE LED with an incandescent they both seemed have about the same response to a short voltage dip.

.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
210423-1409 EDT

ptonsparky:

Which Fluke are you referring to?

The 87V has a spec of --- 250 µS using Peak Capture --- but it is what is says, peak.

Min-max capture is nothing close to this short time, which is 0.25 milliseconds.
I suspect min-max is much closed to a major part of 1 second, or longer.

.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
210423-1953 EDT

ptonsparky:

A further note:

It is easy to build a fast response peak detector. But this will not measure a fast downward change in peak voltage. It is much more difficult to make an instrument that measures the RMS value, or peak, or average, of one half cycle on a 1/2 cycle by 1/2 cycle basis. This later device would be moderately complex.

On my 8 bit resolution digital scope it is hard to see the 2.5 V drop I mentioned in my experiment, but knowing it is there I can see it. I determined the voltage change with my Fluke 27 by maintaining the voltage drop for long enough to see the change on the Fluje 27.

.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
210424-1426 EDT

ptonsparky:

In my post #12 the voltage of the 25 mfd to which it was charged was 28 V not 18V as I wrote.

Today I increased the series resistance to 40 ohms which provides a drop of 5.1 V to the 15 W bulb. Time of drop duration was kept the same. Thus, the flicker is more noticeable, but with same duration, quite short.

Keep in mind that home movies might have a frame rate of 16 per second, and theater films 24 frames per second. Also note that US television is 60 half frames per second (double spacing of the scan lines), and 30 full interlaced frames per second.

When a full TV screen is scanned at 30 frames (525 lines per frame) it is a sequence of horizontal lines being displayed one after another with the duration of one scan line being 1/(30*525) = 1/15750 second, 0.0635 millisecond. 525*0.000,0625 = 0.0328 seconds (1/30 second). Because of the rolling effect of the scan lines you see flicker, whereas displaying a full frame with all pixels displayed simultaneously at 24 per second as in a movie theater you don't noticeably see flicker. And home movies were even slower at about 16 frames per second. But if you maintain a full 525 line TV frame at 30 per second, and interlace half of the lines in one frame and the other half in a second frame, then you can get the flicker effect of 60 frames per second (small), but get the resolution of a full 525 line image.

I think that two 15 W bulbs, one on each phase, is a useful flicker and wiring problem detector. And the cost is low.

.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
210424-1926 EDT

Buck Parrish:

You need to be more informative on how and why a dimmer on a different circuit can cause blinking on some other circuit.

What kind of device on some other circuit is blinking? Are both items on the same phase?

What correlation exists between what the dimmer is controlling, and whatever is the device on some other circuit?

Is the device on some other circuit an incandescent bulb? Have you put an incandescent bulb on said other circuit, and looked for it to blink?

What does the voltage look like on an oscilloscope on the other circuit when blinking of the other circuit occurs?

How large is the load on the dimmer, and what is the nature of that load?

An incandescent is an excellent test device because it is simply a resistor, no other complexity, and has well defined characteristics.

.
 
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