KnightoftheRoc wrote:I'm hearing a lot of talk about inverter use. You need to consider that an inverter IS a transformer, at it's very core- that's why they weigh so freakin much- it's the step-up transformer that changes the low voltage/high amperage (once a frequency has been established in the DC to emulate AC) to high voltage/low amperage power, usable in your home. Depending on the design of this transformer, it may have plenty of wire wrapped in it to act as an antennae and pick up the EMP frequency. I'm no expert on this topic, but having already gone solar is not, IMO, any guarantee against the effects of an EMP, regardless of it's cause.
The big transformers aren't vulnerable because of their own windings, it's because they're connected to a loop antenna with many square miles of cross-section. The fields involved in a geomagnetic storm are far too slow and weak to affect anything small enough to move. If you can pick it up, or even pull it behind a truck, it's too small to care until you plug it into an antenna the size of a small city.
This part's important, so it's time for obnoxious big text in hopes that everyone else will read this bit and I won't have to type it again for a while:For anything you can pick up, you can actually simulate the effect of a geomagnetic storm a hundred times stronger than the Carrington event: Pick the thing up, and turn around very slowly -- take about 30 seconds. The change in the Earth's magnetic field felt by you, and everything you're holding, will peak at about 500 microtesla per minute. The Carrington event peaked somewhere below 5 microtesla per minute. It's that change in magnetic field that induces the currents, and it takes rather sensitive instrumentation to even detect a change that small -- unless you have a freakin' enormous pickup loop. If you can pick it up and turn it around without killing it, a solar storm can't do a damn thing to it.
KnightoftheRoc wrote:An automatic transfer switch sounds good- but how fast does it react? Not fast enough to beat the flow of electricity, I'd bet- that's just a tad under the speed of light. Disconnects and circuit breakers MOSTLY work on heat, which is caused by an increased amperage flow- heat takes time to transfer from it's initial source to the sensor that trips the disconnect- a transfer that can be measured in seconds, in the case of a big transformer, simply from the amo8unt of material involved. I wouldn't bet any money on those being enough to protect much. There are magnetic based circuit breakers out there, but they are much less common, and more expensive, than the standard temperature based breakers. They can react faster, because the magnetic field changes almost as fast as the electrical flow does- a difference that be the deciding factor in "does it catch fire, or not?"
The important thing isn't how fast things travel along the lines, but how fast a surge ramps up the voltage. The direct effects of a geomagnetic storm are laughably slow -- rise times of several minutes, typically. But they can't damage your equipment anyway, because your house isn't fed directly from the long multi-hundred-kV lines. The only risk to your own gear is from the possibility that a failing transformer could produce a surge as it dies, which I expect would be similar to other surges in the grid from other causes. If the gear is designed to withstand the effects of grid hiccups caused by downed power lines and such, it should be fine.
KnightoftheRoc wrote:Something I'd like clarification on, if someone with a PHD can be so kind- does the wiring being affected by an EMP need to be part of a closed circuit to be damaged, or can the effects be so strong as to induce a current in the absence of a complete circuit. My training has always said that a circuit must be closed for current to flow, period, but I doubt they considered this type of scenario, either.
I'm thinking that, if given warning in time, simply turning off the simpler circuits, like that of an electric motor, might be enough to protect them, if the closed circuit is required. Electronic circuits, given the many, diverse pathways involved, probably wouldn't stand a chance if the current were induced along the circuit traces.
Remember to distinguish between a geomagnetic storm and a nuclear EMP. A nuclear EMP involves radio frequencies, which can induce significant voltage in small conductors, with or without a complete loop (this is how your radio picks up signals with a single-ended metal stick for an antenna -- no complete circuit there). But that's not what this thread is about -- we're talking about solar-induced geomagnetic storms, which cannot