Are you sure about that? My electrician buddy who is also a hack knife maker told me that they are not in the sense that you cannot use a single phase/leg (?) AC motor with a VFD.
Quote Originally Posted by Bruno View Post
No. A variable speed AC motor and a fixed speed AC motor are the same. The difference is the drive needed.
AC engines are controlled by changing the frequency of the input signal. For this, a frequency convertor is needed, and decent ones cost money. Sometimes as much or more than the motor itself.