Hi Paul,
I just want to comment on the motor amperage draw question. An electric
motor running no load will have a current draw. When you start to load it,
the current draw will increase. When it is loaded to stall, it becomes
almost a "short to ground". Have you ever got a piece of metal stuck in a
bench grinder or leaned on a small grinder until the breaker tripped?

Dale Davies

I agree but as Bill Schertz pointed out there are electric motors
and then there are electric motors. There are many different kinds
and how the net mechanical power out varies with simple current
and voltage measurements changes.

http://en.wikipedia.org/wiki/Power_factor
In a purely resistive AC circuit, voltage and current waveforms
are in step (or in phase), changing polarity at the same instant
in each cycle. Where reactive loads are present, such as with
capacitors or inductors, energy storage in the loads result in
a time difference between the current and voltage waveforms. This
stored energy returns to the source and is not available to do
work at the load. Thus, a circuit with a low power factor will
use higher currents to transfer a given quantity of real power
than a circuit with a high power factor. A linear load does not
change the shape of the waveform of the current, but may change
the relative timing (phase) between voltage and current.

Circuits containing purely resistive heating elements (filament
lamps, strip heaters, cooking stoves, etc.) have a power factor
of 1.0. Circuits containing inductive or capacitive elements
(electric motors, solenoid valves, lamp ballasts, and others )
often have a power factor below 1.0.

DC motors on the other hand are pretty straight
forward unlike other kinds. DC motors are the kinds found in
cars.

When I say power on a DC motor is volts times amps and 746
watts equals one HP that is the absolute max net mechanical power
that motor will every  generate given 100% efficiency of converting
electric power to mechanical power. However no motor is ever
100% efficient.

Paul Lamar