Sorry, couldn't help notice the "Dueling Banjos" of Sweed and ZX9RBART.
I admire Librarian for wanting to know more about electronics...even though (he admits) it may not expand his ability to improve his XMOD. Never stop asking questions, man!
What ZX9RBART was trying to explain is the difference between amperage and voltage:
Imagine standing on a cliff with a boulder. Voltage is like a way of measuring how high the cliff is. The higher the cliff, the more energy a falling boulder will have. The height of the cliff is the voltage.
Amperage is a related concept. Amperage is the amount of force that the boulder strikes the ground with. Amperage is affected by voltage (how high up you drop the boulder) but is also affected by other factors:
1. the weight of the boulder. Obviously dropping a 1lb. rock won't hit the ground as hard as a 50lb. boulder. This is because force=mass times acceleration. Increasing the mass, increases the force.
2. Wind resistance. Obviously, if you attached a parachute to the boulder, it wouldh't strike the ground with as much force as if it were in true free-fall. This is related to Resistance. In electronic-ese, the better your wires (conductors) the less resistance--i.e., more current reaches the motor with copper wires than with, say aluminum wires. An FET works on this principle--it is a programmable road block to current--from the batteries to the motor. Like ZX9RBART (come on, get an easier to remember screen name! eheheh) said, the FET mod is like getting a bigger spiggot to allow more current to flow.
So for Sweed, it's true, a FET doesn't change how high the cliff is, it reduces wind resistance as the boulder falls (i.e., the boulder is more "aerodynamic").
The reason there is an FET at all on the cars is because it regulates the amount of current per unit time that reaches the motor. Anyone who has overheated a motor understands the usefulness of an FET. The trick is to maximize the amount of current reaching the motor without overheating it.
The manufacturers have "FETed" the cars with a large margin of error so that the motors don't overheat. What the modders have done is basically say, "Yeah, yeah...I know, I don't want to overheat the motor but I think I can put a little more juice through the motor and still not burn it up."
I'm sure I made an error or two in my explanations. Anyone who wants to polish my analogies is welcome to do it. If I left anything out, please feel free.
Hang loose,
--Doc
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