nick4567 wrote: ↑27 Sep 2021, 19:30
no not true harmonics lose strength over distance so if u plug all the lights (in ur home) with fluorescents and max out all the fans at the same time u would recieve a strong effect and definitely strong enough to confirm if harmonics are the problem
Not all fluorescents generate harmonics — some electronic ballasts have excellent power factor correction and doesn’t send any harmonics. I’ve seen a cheap smarthome dimmer also generate harmonics, while a high end Lutron smart dimmer did not, etc.
Also, harmonics can transmit over long distances if strong enough. A harmonic 100 miles away have caused blackouts before (e.g. unsynchronized power generation with AC waveforms slewing against each other, causing a safety mechanism to disconnect automatically from the high voltage transmission grid system). Power generating companies try to keep the 60Hz AC sine wave in sync with each other, with all the generating stations simultaneously synchronized on the entire grid, but it’s possible for them to go out of sync (a mega harmonic). Or somebody’s data centre emergency power generator accidentally shorted into the electrical grid at unsynchronized AC for a few moments (accidental harmonic ripples for a couple of city blocks) until its circuit breaker tripped. That brief harmonic pulse can cause a computer in other buildings nearby to crash. Weird electricity accidents happen unbeknownst to our knowledge all the time that can cause sufficiently-powerful harmonics to ripple fairly long distances — we’re talking about unsynchronized-generator-station harmonics rather than the weaker harmonics of a single motor. In some countries, the generator sync isn’t very good and harmonics ripple far distances, even from two AC curves only a few percent out of phase, or two AC curves bouncing back and fourth (1% ahead, 1% behind, 1% ahead, 1% behind) as two power stations struggle to synchronize to each other on the same grid. By dictionary definition, that falls under the description of a different kind of “haromonic” (even if not traditional harmonics).
Some EMI is many orders of magnitude more intense than other EMI. Not all EMI is the same. It’s a BIGGER difference than light-snow-flurries-for-30-seconds versus blizzard-of-the-century-everyday-24/7-for-a-week. The weakest EMI and the strongest EMI is a bigger difference than the distance between two planets and distance between two galaxies! It’s that BIG a universe of EMI strengths. What this means is that harmonics sufficiently powerful enough (e.g. power generator league) can ripple quite far, even if weaker harmonics fall off very fast.
And EMI may or may not involve harmonics. Both harmonic and non-harmonic EMI are both problems that can affect a computer when the interference is strong enough. They can also be transmitted wirelessly over the air (induction, EMF transmission, etc) — induction can be like a huge old poorly-shielded industrial motor starting up 12 inches away from a computer emitting spark-gap-transmitter style radiation like a well worn 1920s motor (e.g. computer above an apartment mechanical/boilerroom floor, or a computer room next door to large machinery, or the room adjacent to the computer room is an office building’s 10,000-amp electrical transformer room)
So it is possible both of you may be right (in different interpretations) — you’re just talking about different forms of EMI problems.
The EMI / EMF / interference universe is fantastically complex. If we were Geordi from Star Trek the Next Generation and could “see” interference as visible, we’d see over 10^100 different appearances and colors of interference at different kinds of brightness (from super dim candlelight a kilometer away, all the way to being next to a supernova). Interference is such a complex universe, that a simple EMF meter is only a tiny keyhole window that does not reveal even 1% of the nature of interference. Actually, EMF meters are literally only a needle hole the size of an atom — they are helpful but they don’t remotely give you a real picture of all possible kinds of EMI / EMF / interference that can happen worldwide.
It is very humbling.