Hey aandpdan (I've had to devote several hundred thousand neurons to mastering the spelling of your nickname!!)
Actually, I think we're now in agreement. Yes, voltage is still being applied to all the electrons, including the ones that are no longer part of the current as a result of the power having been turned down on Device X. But the generator is not transferring its kinetic energy any longer to those suddenly-excluded-from-the-current electrons, which causes the generator to briefly speed up its rotation rate until the governor can reduce the flow of fuel and bring it back to 3600 rpm.
So I have a clear idea of that now (and I'm appreciative of the role you and
[email protected] played in driving me to abandon my original misconceptions), although I do still have a sense of uncertainty about what is going on with the electrons when they are "under electrical pressure" but are not part of a current. Electricity is conventionally compared to water flow, so let's consider a situation where you have a sink with the faucet turned completely off. The molecules of water are under pressure, and the instant that faucet is turned on they will spurt out---but what about their state before the faucet is turned on. They have not acquired any kinetic energy (which is why the electrons in that situation allow the generator to speed up, and then be throttled back to save fuel in maintaining 3600 rpm) but it's clear that "something" is happening to them. The fact that the water molecules are unable to move means no KINETIC energy is being transferred to them, but clearly a force is being continuously applied to keep them in that pressurized state. Now applying that concept to the electron situation, how do you parcel out the amount of energy (or fuel) necessary to apply the force that merely keeps the electrons in the pressurized state versus the amount of fuel necessary to apply both that force and also the force that drives them in currents of various sizes?
So for example, if the generator has no electrical devices active at all (zero load) but is spinning at 3600 rpm and creating its normal pressure (voltage), what amount of energy is necessary for that versus spinning at 3600 rpm while producing, say 10 amps of current? In thinking about that, it seems that there never would literally be zero load, since amps=volts/ohms so with anything less than infinite resistance there'd always be some current. So as I type my question, I think I see how to derive the answer: Find out how many ohms are involved when you turn off all the devices on the circuit, then calculate the amps in that state (using the voltage the generator is producing), then determine the wattage, amps X volts. Then take the amps when Device X is on, multiply it by the voltage, and voila!
It seems that if we use 120 volts, and some arbitrarily high resistance that would effectively keep the devices "off" (would 100 ohms be reasonable? I have no idea), then we have 1.2 amps X 120 volts=144 watts of power consumed by the generator when it's not supplying current (for all practical purposes) to any devices. And 1200 watts of power when it's supplying 10 amps at 120 volts. So the generator would consume only 144/1200=0.12, only 12% of the fuel when not powering any devices compared with supplying 10 amps. But that assumes my choice of 100 ohms was reasonable. I'd like to know: What is the correct amount to use?
Wait a minute, that can't be right. I'm realizing that not only didn't I take into account different levels of efficiency for the generator at different wattages, but, much more importantly, what about just the idea of a generator as a motor, spinning around without even producing any voltage at all--wouldn't that have to be calculated as well and considered a "base" state? In fact, that would be a very significant amount of energy I imagine.
(An important aside: thinking back to the water analogy--- Clearly NO water whatsoever is getting out of the faucet, and yet force is being applied to keep the water under pressure. So what do you do to calculate the force in that situation? In the electrical situation, we're using some hypothetical amperage that would still flow with high resistance. Now that I apply the water analogy, I question whether that is really a sound analysis!!)
So we really have three separate fuel issues (maybe more, I may be missing some!) First, the generator just as a motor, requiring energy (fuel) even without producing voltage. Second, we have the generator producing voltage but not powering any electrical devices. Third, we have the generator powering a 10 amp device.
Oh my God, the complications never end!!!
Anyone who can provide enlightenment is welcome, in fact is eagerly sought! I really want to understand every detail of this.