Quote:
Originally posted by Ulibrium
If the resistance is constant, doesn't that mean voltage and current will be related the same way regardless of the torque of the motor?
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Yes. If you have a 600 Ohm resistance, and you put 12V across it, the current through that resistance will *always* be 0.02A. (Current = Voltage / Resistance : 0.02 = 12 / 600)
When the Victor increases the voltage, and the current rises, the *total power* going though the motor increases (remember, Power = Voltage * Current). The motor uses this power to create a magenetic field that is "more" (sorry, the exact physics of the feild I'm not too sure of, can somone else help me out on this?). As such, the motor spins faster and harder. Nifty home experement: Connect a small motor to a power source through a potentiometer. Measure the voltage and current going though the motor as you increase and decrease the resistance. You can get a feel for speed by looking at the shaft, and for torque you can feel how hard it is to stall the motor with your hand. Or if you're willing to take my voltage/current/resistance formula on faith (Ohm's Law), then just think of a drill... if you spin it slowly, the voltage is low, so the current is low, so it is easy to stall. If you spin it at full speed, the voltage is higher, so the current is higher, so it is harder to stall.