ECN Forum Forums General Topics of the Trade General Discussion Area capacitive coupling

a good thread here.
It sheds light on Soares using the term 'Capacitive Coupling' as pertains to a delta system.

thanks so much to everybody that added their thots, this was totally helpful. raised more questions but is a good catalyst for getting back to my old books. you probably think i havent studied any of this before but, embarrassed to say that i have, and forgot a lot of it or maybe thot i knew it but apparently misunderstood, but was able to get enuf right on tests to get thru in the field you're busy working and figuring out ways to save time & cut corners & stay up with the [pardon me frinch] freeking codes, not much time to think

not rocket science, but anyway these concepts were very helpful to get straight: the inductive "magnetic field" coupling between transformer primaries to secondaries vs. the "electric field" capacitive coupling
[line charging] of something like long GFCI circuits that could make enuf current to trip them if their settings were too low.
and this from another thread, seeing that the electrons are trying to return to their source instead of the earth [really just another big conductor]. i think when i re-read my books these ideas will put it a new perspective.

kind of a last thing that might help is examples if anyone has any that might bring this back down to a "working in the field" level, like scotts Line Charging [Capacitive Coupling] GFCI example, or george's motor not stopping, [sorry but the Caesars Ghost thing must have been from years B.C.indy, didnt help], & paul's switch loop.

when you wire a fluorescent ballast, its just wiring to the ballast, where is the power factor correction capacitor that adjusts for the phase difference in the current and voltage?

there's a capacitor in a control box mounted in a pump house for submersible pumps, what is that doing? starting circuit vs. running circuit, right? sorry, thot i was thru asking questions

any other capacitors i should be familiar with that i probably work with regularly? and why they're used?
-C-

I guess for many people who want to know just enough to do their job, the theoretical side can seem daunting and even unimportant. But I'm firmly of the opinion that we should understand WHY we do something (instead of just saying "because that's the way it's done"). That theory may suddenly become very useful when running up against a less common problem.

Of course, I'm just an electronics nut who's wanted explanations of everything since the age of about 5. Others may see it differently!

The capacitor in the control gear of the pump motor is most likely part of the normal split-phase induction motor. It's used to generate the appropriate phase shift to the auxiliary windings to obtain the rotating field needed to start the rotor turning.

There are some variations in fluoro. light wiring. I don't think I ever had cause to open one up while I was in America, so the others will have to clarify that point.

Most conventional fluoro's in the U.K. have the p.f. correction capacitor just clipped inside the housing and wired directly across hot & neutral at the terminal block. Many cheaper types sold for domestic use don't bother with it; the lower p.f. of one or two fittings is considered inconsequential. (And it saves all of $2 per fitting!)

Capacitors are used widely throughout electronics, but one other area that may be of concern to you is filters in power supplies.

These typically have caps. connected H-N, N-G, and H-G in combination with some series inductors. It's becoming more of a problem in big offices, etc., where with dozens of computers in use the leakage current to ground can be appreciable.

I like teaching, but the 2nd semester of the year is also open to all electricians, apprentices and journeyman alike. I appreciate the reactions I get from the apprentices, but maybe even more are the reactions I get from some "geezer" such as myself who has not been in his books for a long time. It's like revelation that "Oh yeah, I studied that 20 years ago, but NOW it makes sense". You will NEVER quit learning in this trade I don't care who you are or how hard you studied. While I usually go for the short answers in these forums, luckily we have guys like Pauluk who will take the long way home, it is what makes this the most valuable electrical forum on the net.

Gotta second that George......

Cindy,
well put here....job desrip or resume' material !