Re: Found a brand new Comp USA PSU
1. Those big oil filled transformers can be damaged by the high frequencies.
2. You beat me to it. Yes, poor power factor leads to problems with current measurement, and the current waveform can become very distorted. Just because of that, measuring the mains voltage with a poorly functioning meter can give you crazy results. As far as I know, its because the meter has a sampling rate at which it samples the voltage, and calculates the RMS value based on those samples. If it has a slow sampling rate, then it is less precise. It may sample just when there is a noise spike on the waveform, and it will change the ultimate reading of the meter. Don't take that word for word, it's only my theory :P
Edit: a pdf from EATON talking about harmonics in the power grid.
Edit 2: Another PDF, from Danfoss, has more diagrams and math
Originally posted by tom66
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2. You beat me to it. Yes, poor power factor leads to problems with current measurement, and the current waveform can become very distorted. Just because of that, measuring the mains voltage with a poorly functioning meter can give you crazy results. As far as I know, its because the meter has a sampling rate at which it samples the voltage, and calculates the RMS value based on those samples. If it has a slow sampling rate, then it is less precise. It may sample just when there is a noise spike on the waveform, and it will change the ultimate reading of the meter. Don't take that word for word, it's only my theory :P
Edit: a pdf from EATON talking about harmonics in the power grid.
Edit 2: Another PDF, from Danfoss, has more diagrams and math
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