I have a motor I wish to evaluate. I wish to measure the Joules input and output. I believe I am making several errors. Right now I measure the voltage and amperage, calculate watts, and assume that for every second this wattage stays the same. So V*A*seconds = Joules input To calculate heat output in Joules I use current squared times resistance. Another energy output is RKE, rotational kinetic energy. I measure RPM, convert to radians per second, determine moment of inertia of the rotating mass, and then use: RKE = 1/2 * MOI * rps^2 Again, units are Joules. This is a start. But are there errors above?