If you have a 100W electrical load and you drive 100W plus efficiency losses, say 110W, into the generator, things will be in a state of equilibrium, with 100W being converted from mechanical input power into electricity, and the other 10W of mechanical input power being eaten up by losses.
Now suddenly put 1kW of mechanical power into the machine; at that instant, before the rotational speed can change, the 100W electrical load will continue to present the same mechanical load to the prime mover. Things will not be in equilibrium, and the machine's rotational speed will accelerate. Depending on circumstances, this may or may not increase the electrical load. Certainly the generated voltage will go up, and any simple resistive load will therefor absorb more power, but maybe you have some regulation such that the load continues to draw exactly 100W.
So assume the load continues to draw exactly 100W. Where does the extra 900W of mechanical power go then? The machine's speed must increase until the losses equal the mechanical driving power; so it ends up turning extremely fast, the increased power going into increases in friction in the bearings, windage loss due to the rotating parts, eddy currents in the magnetics (and doubtless a couple of other things I forget at the moment), none of which are desirable.
You would find that, without exceeding the machine's electrical rating, you would quickly exceed its mechanical ratings, i.e., probably long before you got to 1000W, the rotation speed would be several times the suggested speed, and catastrophic failure would likely result. Note you can do this with no electrical load on the generator at all.
Yup. That would be the still amazingly low priced at $49, even after being in publication for 90 years, Radio Amateur's Handbook. This book was my electronics & radio bible all through high school. Most of the theory I learned before studying EE in university came from it.. If you don't want to buy one, most libraries have back issues.
Best Answer
A coilgun is a series of coils that are successively energized as a conductive projectile made from magnetic material passes by them.
Each stage acts on similar principles to those of a solenoid. Current loops induce magnetic flux through their center:
As the conductive projectile approaches the air-core current loops, two things happen: the loop inductance increases and the projectile becomes magnetized. The magnetized projectile is then attracted to the loop magnetic field, accelerating towards it. As it approaches, inductance increases, completing a positive feedback loop such that the pull on the projectile and magnetic field created by the loops increase.
This process reaches a peak when the projectile is completely enclosed by the coil, where further travel decreases the loop's inductance. At this point, current through the loop is abruptly turned off so the projectile won't be slowed down by its continued attraction to the coil's magnetic field.
These are the basic physics principles by which a coil gun operates, which appears to be what you are interested in. There are many practical implementations.