The gotcha in using Ohm's law in all this is that the motor is not a resistor.
Long story short, when a motor runs, it generates a 'back voltage' that opposes the voltage applied to it. A motor will accelerate only until the 'back voltage' equals the voltage applied to it.
If you measure the voltage and amps through the motor at one voltage and calculate the resistance you'll come up with an equivalent 'resistance'. If you then change the voltage and calculate a second resistance, you'll come up with a different equivalent resistance.
In engineer speak, the 'equivalent resistance' is non-linear as the voltage is varied. In plain English, every time you change the voltage applied to the motor, the equivalent resistance will also change.
Bill, not Keesler, they kept me at Lackland AFB in the secret building without windows.
If anyone is curious, I blame my knowledge of things electrical on an incident when I was about 10 or 11. Growing up on a farm, one of my chores in the summer was to take a scythe and cut the grass under the mile or so of electric fence lest the fence short out on all the grass and the cows get out.
Being none to interested in the job at hand, one day I begin to wonder if electricity could run upstream faster than water would run downstream. It was only a matter of time before I applied the only stream at hand to the fence and got my answer.
BOY HOWDY DOES IT EVER GO UPSTREAM FASTER!!!!
