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  1. st50maint

    14 % Harmonic Distortion at residential customer

    5 days ago I went to a LIPA customer service office. The representative gave me a couple of names to call in the "Electric Construction" department. The woman who answered my call actually seemed interested in my problem and said she would have the appropriate person call me back that day. I...
  2. st50maint

    14 % Harmonic Distortion at residential customer

    mmt019, Thanks for your suggestions. I have already done them. My neighbors also have the problem. Here is the latest Email response from LIPA. Thank you for contacting online services. The initial investigation involved electric service securing the connections between the pole and the...
  3. st50maint

    14 % Harmonic Distortion at residential customer

    The first post was not formatted properly to show the picture. Here it is now.
  4. st50maint

    14 % Harmonic Distortion at residential customer

    After 4 good months the problem has returned. I have had 14% distortion for the last 10 days. I am not looking forward to calling customer service. If any new readers of this old thread have any suggestions, they will be greatly appreciated.
  5. st50maint

    Distorted residential power, only at night?

    Got home from work yesterday and found a tag on the door from the power company. At 1 PM they had checked my power and found no problems. I had called last week and again explained that the problem was only at night yet they still come during the day.
  6. st50maint

    Distorted residential power, only at night?

    Oddly enough the unit with the buzz is an AC power regenerator that feeds AC to the tube amplifiers. It is a PS Audio- Power Plant Premier. I suspect that it does have some sort of SMPS.
  7. st50maint

    Distorted residential power, only at night?

    The buzz is not heard from the speakers. It is heard faintly from the electronics, noticeable only when the speakers are silent.
  8. st50maint

    Distorted residential power, only at night?

    No, my Tektronix RM504 can not do FFT. However, I did hook up an audio distortion analyzer to the AC. It reads about 3.5 percent THD all the time. I assume this means that the problem is not harmonically related to the 60 Hz.
  9. st50maint

    Distorted residential power, only at night?

    Power is still bad. At first I thought it was good but it turns out that they reversed the two legs which put the problem leg on different outlets.
  10. st50maint

    Distorted residential power, only at night?

    The power company showed up at my house at 8 am today. The gentleman was not aware of the exact complaint. I explained that it only happened at night and showed him pictures of the waveforms. All he could do is check my service as he would normally do. Everything measured OK but he elected to...
  11. st50maint

    Distorted residential power, only at night?

    I went to the power company's office today. I asked to talk to a technical person but was denied. However, they took my information and pictures and said it will be looked into. We will see if anything happens
  12. st50maint

    Distorted residential power, only at night?

    I am starting to think that maybe it is the power company's problem as someone has suggested. I did not originally think so because only one leg from the transformer caused problems with my equipment. Also the scope waveform was much cleaner than on the problem leg. I increased the gain of the...
  13. st50maint

    Distorted residential power, only at night?

    It is always good when I get up about 8 AM. It is always bad when I get home after dark. The few times I have been able to observe the transition it has been fairly accurate and repeatable, within minutes of my street lights going on or off. "Is the time this starts in the evening and ends in...
  14. st50maint

    Distorted residential power, only at night?

    I have switched off all breakers except the one powering the scope. Then I put the scope on a different line and shut off the original breaker. This was done at the outlets closest to the circuit breakers. I am pretty sure that there are 14 houses on the transformer. I am not aware of any...
  15. st50maint

    Distorted residential power, only at night?

    The flattening of the waveform is not what comes and goes. It is the spikes just after the peaks that I am concerned with.
  16. st50maint

    Distorted residential power, only at night?

    For many weeks I have had this problem with my power. I hear a slight buzz from my audio equipment, only at night. Hooking up an oscilloscope shows this waveform. ? At dusk the waveform becomes dirty. At dawn it becomes clean. Everyday like clockwork. Some more clues: 1. The problem is only...
  17. st50maint

    14 % Harmonic Distortion at residential customer

    No, LIPA did not tell me anything about the fix.
  18. st50maint

    14 % Harmonic Distortion at residential customer

    The problem has been corrected by LIPA. Distortion now measures 2.6%. Thanks for the help.
  19. st50maint

    14 % Harmonic Distortion at residential customer

    When the scope photo was taken, the audio equipment was shut off. The only items drawing significant current were incandescent light bulbs and the vacuum tube oscilloscope itself. The problem is not only in my house. I borrowed test equipment from work and tested my neighbor’s house. I...
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