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Q & A: RPMs knowing Volts and Ohms?

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Most recent answer: 04/12/2010
Q:
I have a small electrical DC motor and I want to know how much RPM does it revolute when I operate it. Knowing the voltage source (16V) and the motor's inner resistance (16 Ohms) is there any way I can calculate the operating RPM with that data? Thanks in advance
- William
Canada
A:
No, the only thing you can determine is the amount of current flowing, I = V/R.  Although the angular speed of the motor does depend on the voltage, it also depends on several other variables: construction of the windings, friction in the bearings, etc.   The best you can do is just to measure the rotational speed with a tachometer. 

LeeH

(published on 04/12/2010)

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