krpm

thousand revolutions per minute

Angular speedexact by definition

A thousand revolutions per minute is 2000π/60 rad/s, about 104.72 rad/s. It is the convenient unit for high-speed rotation: machine tool spindles run 10 to 40 krpm, automotive turbochargers 100 to 250 krpm, and dental handpieces up to 400.

Watch out: At these speeds the limit is usually not the motor. Bearing DN number (bore diameter in millimetres times rpm) and the burst speed of the rotor set the ceiling, and balancing tolerance requirements tighten with the square of speed.

1 krpm 104.71976 rad/s