Sory to say that you are wrong Winston, in fact I have never heard that explanation in working with electrickery in the last 40 years.
An Alternator (or generator) is designed to operate at a certain voltage, with a capacity to deliver a maximum current of what ever it may be. The regulator keeps the voltage constant ( in our case 13.8V approx). As more current is drawn, the voltage tends to want to drop, so the reg works to keep it where its supposed to be.
An analogy would be a water tank on a high stand, with a pump to keep it full and a feed pipe. The tank will have a certain head of pressure, that will start to drop slightly as the water flows out through the tap . As the level in the tank drops, the pump turns on to refill the tank..