Beaver53,
I don't know the answer to your question. This is how I understand it. Voltage is the power, or potential that powers a device. Amperes are not something
supplied to a device, but a measurement of the current
used by the device to create work.
The heater motor can have 12 volts ready and waiting to do work...but until the motor turns on, no work is being done..no current is flowing.
Regarding your hypothetical generator, my guess would be, yes, it would run the motor. Although I am not a electrical engineer, I think the current draw of the motor is a function of the voltage supplied, but also of its construction.
Electric motors, both AC and DC are a science in themselves.
Electrical concepts are tough to visualize. It is possible to prove them using Ohms Law, but that does little for the person like me that needs to see and touch things to really understand them.
This topic has come up before and turned into a biggest bag of worms the world has ever seen.
Maybe someone will show up that can explain this clearly to both of us.
Stuart