Continous power dc motor

[amgen]

Does the load change or is it constant ?? are you going to continually read power or just make some estimations for your project ??
The motor current is related to the loading of the motor (how much effort the shaft is requiring ) , so if the current goes to zero, there is no power being consumed (E X I) by the motor at that time, in fact if the load tries to turn the motor shaft faster then it would normally run at that voltage, the motor then becomes a generator and current tries to flow back to the supply.
Power,
....you have instanteanous power, the E X I at an instant
....average power, a sumation over a period of time say 1 second
....and watt/hours or kw/hours

for PWM and power, I think you can relate the PWM % to the voltage, for example 12 volt DC at 50% PWM would be 6 (for E) X I (current). take 10 or 100 readings per second and do some calculations to obtain power usage.

don
amgen