[time-nuts] AC line distortion
adrian.rus at broadhurst.ro
Tue Oct 4 07:29:05 EDT 2016
Maybe living on other "countries" ? :)
When you live at the end of the power line, at many km from the last low voltage transformator and when the lines are over-loaded, their distributed inductance + their distributed capacitance [?] make the voltage hump to "sleep". It's rising front is longer and is decreasing front, shorter.
I have had a massive surprise when hooking the oscilloscope to the line... what do you think, it was the dream of my life to to buy a 3kVA dual conversion inverter for lab purposes? :)
Until the purchase, no real/realistic AC harmonic compliance measurements were possible [IAS/EN61000-3-2]
Using the AC mains for time keeping is not a good strategy, too. The 50Hz mains frequency is a sort of 50Hz. It is a performance measure of the national grid authority: when it does not manage to shut down the suppliers on low demand conditions the freq exceeds 50Hz and when in need of energy but unable to cold start the suppliers, the freq dip below 50Hz.
From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Thomas D. Erb
Sent: Tuesday, October 4, 2016 2:02 PM
To: time-nuts at febo.com
Subject: Re: [time-nuts] AC line distortion
Maybe a capacitive load in your facility ? Whenever I've looked at it - it's always been pretty clean. For years we used the AC mains for time keeping - but have found in some locations - especially ones with lots of dimmers - zero crossing counting was ineffective. My feeling was that dimmers that chopped the ac wave form in the middle sent out a large amount of noise over a wide spectrum.
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