- Is it AI or not - 1 Update
- Ground fault switch aka residual-current device - 3 Updates
| vjp2.at@at.BioStrategist.dot.dot.com: Aug 15 09:34AM I used "AI" since 1978. But every few years, what used to be AI becomes commonplace and stops being alled AI. Character and voice recognition, file completion, symbolic manipulation (Macsyma, Wolfram), ELIZA psychanalyser, were once called AI. Then again, I'm a 62yo (familially) third generation computer user as well as a third generation engineer. If you used Marvin Minsky's fifty year old psychanalysis program ELIZA (available in emacs as doctor; I use it for night time OCD panic attacks), ChatGPT looks awfully boring. I've used fractals (EXCEL:LOGEST) for fraud detection for four decades. Gregory Nazianzen, the Great, tells us all creativity is divine (28:6; 1 cor 3:5-9) and denounced anti-science at Basil's funeral (42:11) as ignorant, lazy and stupid. (My namesake, Basil of Caereria, was a physician, who invented the concept of a hospital.) This may be found on p151 of the 1977 OEDB Patrsitics textbook used in high schools in Greece (Evagelos Theodorou, Anthology of Holy Fathers.) More completely from Florovsky v7 p109 "We derive something useful for our orthodoxy even from the worldly science.. Everyone who has a mind will recognize that learning is our highest good.. also worldly learning, which many Christians incorrectly abhor.. those who hold such an opinion are stupid and ignorant. They want everyone to be just like themselves, so that the general failing will hide their own" -- Vasos Panagiotopoulos panix.com/~vjp2/vasos.htm ---{Nothing herein constitutes advice. Everything fully disclaimed.}--- |
| Jerry Peters <jerry@example.invalid>: Aug 14 06:18PM > In theory, the Neutral and the Ground should be at equal potential - thereby avoiding false trips - as that is what the GF device is looking for - current going to Ground (or somewhere), not Neutral. If the Ground and Neutral are not at equal potential - there may be something for the GF device to detect. > Peter Wieck > Melrose Park, PA This make no sense, the GFCI doesn't care about the ground wire, it measures the difference in current between the 2 supply wires. Look up a datasheet for the LM1851 IC, it will show sample circuits for a GFCI, there's no connection to the ground wire at all. In fact you can use a GFCI on an ungrounded circuit and it's still functional. |
| Brian Gregory <void-invalid-dead-dontuse@email.invalid>: Aug 14 08:46PM +0100 On 11/08/2023 23:43, Carlos E.R. wrote: >> limit and a little bit of extra harmonic content pushed it over the edge? > That incorrect wiring, as plotted, doesn't increase the residual current > even one mA. There has to be something else. I may be confused. What do you mean by protector? -- Brian Gregory (in England). |
| dplatt@coop.radagast.org (Dave Platt): Aug 14 04:02PM -0700 In article <ubdr64$2duqe$1@dont-email.me>, >for - current going to Ground (or somewhere), not Neutral. If the Ground >and Neutral are not at equal potential - there may be something for the >GF device to detect. That's almost exactly backwards, in practice. When the system is in use (that is, when the Hot line is drawing current), the Neutral and Ground wires are at the same potential *ONLY* at points where they are actually bonded together - that is, at the panel or sub-panel or transformer. At other points (for example, at the outlet) they won't be at the same potential. They can't be, because the neutral wire is carrying current and has non-zero resistance, and thus has a significant voltage drop between the outlet and the panel. The protective-ground wire won't be carrying current, and thus has no voltage drop between the outlet and the panel. So, if a GFI considered "ground and neutral wires are not at equal potential" to be a fault condition, it would trip every time somebody turned on a light or appliance. If you want to see this demonstrated, it's not difficult to do, if you have an AC voltmeter with properly-shrouded insulated test leads. Using one half of a standard outlet, measure the voltage between the neutral and ground contacts. If nothing on that circuit is drawing current, it should read 0 volts, or within noise-factor of that. Then, plug a 15-amp space heater into the other half of that outlet, and turn it on. You'll almost certainly see a significant voltage develop between ground and neutral, caused by the current flowing from the outlet back to the panel through the neutral wire. I'd expect something on the order of a volt or so to show up on the meter. If you don't see a voltage drop between ground and neutral under these conditions, it may very well mean that your outlet is mis-wired, and has ground and neutral connected together at the outlet... which is a definite no-no. |
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