Revolutions per minute
rpm (revolutions per minute) is an Anglo-American unit in mechanics for the rotational speed for example of a rotary axis.
The German unit of measurement for corresponding to rpm is 1/min (= 1 min-1).
According to the SI system of units, the specification in the unit 1/s is intended but hardly in use; the unit Hertz is not to be used for the rotational speed according to DIN 1301.
The special name revolution (unit symbol r, in German-speaking countries U) is usually used instead of one as a unit in the specification for rotating machines. Correspondingly, the unit "revolutions per minute" (unit symbol U/min) is widely used for rotational speed.
If we consider a point on a component rotating with the axis, it moves with angular velocity ω .
To an belongs a ω
Here stands for the numerical value of the speed in the unit used.