Quote Originally Posted by BuffaloJohn View Post
He has three phase motors from the treadmills - thus they are controlled by frequency using a VFD - variable frequency drive.

Three phase motors are induction motors. While there is a voltage component of the VFD, the primary control of speed is the frequency of the AC 3 phase waveform (there is a voltage component in VFDs which is used to keep the motor from overheating by keeping the magnetic flux within the design parameters).

Yes there are many treadmills that as DC motors, but not these...
I stand corrected. Thank you.