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TWACS flickering?

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Hv&Lv

Senior Member
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Engineer/Technician
How many have ever heard of TWACS causing flickering lights?
Anyone ever ran into a flickering lights problem that can’t be explained any other way other than signal modulation due to the POCO communication system?
 
E

Electricmo

Senior Member
Location
Missouri
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Lineman
Hv&Lv said:
How many have ever heard of TWACS causing flickering lights?
Anyone ever ran into a flickering lights problem that can’t be explained any other way other than signal modulation due to the POCO communication system?
Click to expand...
How many people know what TWACS is? I can hear a meter vibrate here when I remotely read it if I’m standing next to it. Your flickering lights scenario is interesting. We are experiencing a lot of harmonics here due to a large influx of LED lighting. It is causing some flickering on led circuits. I will consider the TWAKS angle on our next complaint call and see if it’s a viable issue.
 
synchro

synchro

Senior Member
Location
Chicago, IL
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EE
The guy on the following video is showing a 60Hz waveform where the zero crossings are modulated by TWACs once in a while, and he's mentioning when the lights are flickering in response to the outbound modulation from the POCO. This occurs near 0:10, 2:24, 2:42, 2:53, and 3:08.


I'm thinking that the flickering would be more prevalent when the dimmer is turned down, because a given change in the zero crossing would be a higher percentage of the ON time of the light.
 
H

Hv&Lv

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synchro said:
The guy on the following video is showing a 60Hz waveform where the zero crossings are modulated by TWACs once in a while, and he's mentioning when the lights are flickering in response to the outbound modulation from the POCO. This occurs near 0:10, 2:24, 2:42, 2:53, and 3:08.


I'm thinking that the flickering would be more prevalent when the dimmer is turned down, because a given change in the zero crossing would be a higher percentage of the ON time of the light.
Click to expand...
Yeah, I have that video..
That is from one guy though..
Im looking for some other experiences, if there are any.
I have a case in with Aclara looking at filters and other flickering lights cases.
also looking into the notion that all UPB dimmers are affected?
 
hbiss

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Should be a simple matter for the meter manufacturers to incorporate a filter on the load side of their meters should this be shown to be a problem.

-Hal
 
synchro

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
Hv&Lv said:
Yeah, I have that video..
That is from one guy though..
Im looking for some other experiences, if there are any.
I have a case in with Aclara looking at filters and other flickering lights cases.
also looking into the notion that all UPB dimmers are affected?
Click to expand...
I didn't find much beyond that video.
But here are some observations based on what's in the video:
There was no mention about flickering when inbound current pulses from the meter (that cause visible voltage pulses due to impedance) can be seen at 0:07, 0:037, 1:07, 1:37, and 2:07.
Flickering was mentioned at 0:10, 2:24, 2:42, 2:53, and 3:08 when the outbound signalling from the POCO that has relatively low frequency content distorted the waveform near the zero crossing. The applied distortion appears like it might consist mainly of a segment of a 60 Hz 5th harmonic. There were a few times when there was outbound signalling present but flickering was not observed such as at 2:35. In this case the waveform distortion appeared to be applied after the zero crossing. Because the UPB communication occurs before the zero crossings as indicated in the patent linked below, that's probably why it wasn't affected in this case and so no flickering occurred.

Filtering could be effective in removing the higher frequency inbound pulses from the meter (with 4-40KHz content), but at least based on this video they were not associated with the observed flickering. The modulation for the outbound signaling that appears to be causing the flickering has very low frequency content and so it's unlikely to be affected by the typical low-pass filtering used for interference mitigation.

 
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C

CaballoRanch

Member
Location
New Mexico
Occupation
Rancher
I have Aclara (TWACS Signal) metering system installed on the pole at my home. PCS, WS1DL-6 UPB dimmer switches were installed throughout (60-65 each). They were receiving interference from the meter while it was reading my usage. Sierra Electric (New Mexico) asked Aclara to have my readings reduced from hourly, to once each 24 hour period at 12:00 midnight. This really helped the EXTREME flickering each hour of the day.
I still have flickering issues with both LED and Incandescent light fixtures. Sometimes a quick bling; maybe 15-45 minutes later I could get another blink or a flicker.
I have installed LDS-120 stabilizers and IRL-1oK resistors in parallel with the load/neutral on each switch with no noticeable change. I've swapped incandescent lamps with LED and vice versa; no change.
What I've finally tested was installing four Simply-Automated US40-11 dimmer switches in place of four PCS, WS1DL-6 switches. The flickering and blink issues disappeared entirely. That was great to see after many months of playing with this mess. The problem now is that Simply-Automated appears to no longer be operating their business.
Can anyone tell me why the Simply Automated US11-40 dimmer will operate the lights without any flickering and the PCS UPB, WS1DL-6 dimmers allow blinking and flickering off and on daily?

LED/CFL Dimmer (WS1DL) - Powerline Lighting Systems - PCS

www.pcslighting.com www.pcslighting.com

Simply Automated -- Universal Dimmer Controller Base -- Model: US2-40

Simply Automated Universal Dimmer Controller Base - US2-40 - with 13 faceplate options in 6 colors.
www.simply-automated.com
 
tom baker

tom baker

First Chief Moderator & NEC Expert
Staff member
Location
Bremerton, Washington
Occupation
Master Electrician
CaballoRanch said:
I have Aclara (TWACS Signal) metering system installed on the pole at my home. PCS, WS1DL-6 UPB dimmer switches were installed throughout (60-65 each). They were receiving interference from the meter while it was reading my usage. Sierra Electric (New Mexico) asked Aclara to have my readings reduced from hourly, to once each 24 hour period at 12:00 midnight. This really helped the EXTREME flickering each hour of the day.
I still have flickering issues with both LED and Incandescent light fixtures. Sometimes a quick bling; maybe 15-45 minutes later I could get another blink or a flicker.
I have installed LDS-120 stabilizers and IRL-1oK resistors in parallel with the load/neutral on each switch with no noticeable change. I've swapped incandescent lamps with LED and vice versa; no change.
What I've finally tested was installing four Simply-Automated US40-11 dimmer switches in place of four PCS, WS1DL-6 switches. The flickering and blink issues disappeared entirely. That was great to see after many months of playing with this mess. The problem now is that Simply-Automated appears to no longer be operating their business.
Can anyone tell me why the Simply Automated US11-40 dimmer will operate the lights without any flickering and the PCS UPB, WS1DL-6 dimmers allow blinking and flickering off and on daily?

LED/CFL Dimmer (WS1DL) - Powerline Lighting Systems - PCS

www.pcslighting.com www.pcslighting.com

Simply Automated -- Universal Dimmer Controller Base -- Model: US2-40

Simply Automated Universal Dimmer Controller Base - US2-40 - with 13 faceplate options in 6 colors.
www.simply-automated.com
Click to expand...
This is a separate poster from the original thread, the OP is asking a question and it does not appear to be a DIY
 
C

CaballoRanch

Member
Location
New Mexico
Occupation
Rancher
CaballoRanch said:
I have Aclara (TWACS Signal) metering system installed on the pole at my home. PCS, WS1DL-6 UPB dimmer switches were installed throughout (60-65 each). They were receiving interference from the meter while it was reading my usage. Sierra Electric (New Mexico) asked Aclara to have my readings reduced from hourly, to once each 24 hour period at 12:00 midnight. This really helped the EXTREME flickering each hour of the day.
I still have flickering issues with both LED and Incandescent light fixtures. Sometimes a quick bling; maybe 15-45 minutes later I could get another blink or a flicker.
I have installed LDS-120 stabilizers and IRL-1oK resistors in parallel with the load/neutral on each switch with no noticeable change. I've swapped incandescent lamps with LED and vice versa; no change.
What I've finally tested was installing four Simply-Automated US40-11 dimmer switches in place of four PCS, WS1DL-6 switches. The flickering and blink issues disappeared entirely. That was great to see after many months of playing with this mess. The problem now is that Simply-Automated appears to no longer be operating their business.
Can anyone tell me why the Simply Automated US11-40 dimmer will operate the lights without any flickering and the PCS UPB, WS1DL-6 dimmers allow blinking and flickering off and on daily?

LED/CFL Dimmer (WS1DL) - Powerline Lighting Systems - PCS

www.pcslighting.com www.pcslighting.com

Simply Automated -- Universal Dimmer Controller Base -- Model: US2-40

Simply Automated Universal Dimmer Controller Base - US2-40 - with 13 faceplate options in 6 colors.
www.simply-automated.com
Click to expand...
Is it possible that a Harmonic Rectifier could eliminate the flickering issue I am experiencing? I located one at this site https://saticshield.com/energy-management-system/power-perfect-wire-in/
 
grich

grich

Senior Member
Location
MP89.5, Mason City Subdivision
Occupation
Broadcast Engineer
Since we're playing with zombie threads, anybody know how LED lights react to a Simplex clock motor-generator? I figure if anything's gonna make a LED light go nuts, it would be a 3500Hz 4-volt signal riding the 60Hz wave. Back in the last century I could hear the ballasts in the HID lights sing when the correction signal was on the AC line.
 
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