VFD frequency to speed calculator

Motor and machine speed at any drive output frequency.

Calculating…

How it's calculated

N = N_rated × f ÷ f_rated Output speed = N ÷ gearbox ratio

A VFD changes motor speed almost in proportion to output frequency. Using the nameplate speed, rather than synchronous speed, includes typical slip.

Below rated frequency, a V/Hz drive gives roughly constant torque.
At low speed, a self-cooled motor loses cooling air. Check the manufacturer's derating for continuous low-speed running.