Most pumps and fans operating in industrial and commercial applications are currently driven by AC induction motors. “ACIM”, which stands for “alternating electric current induction motor”, is an asynchronous type of motor that relies on electric current to carefully turn the rotor. Torque is usually produced by electric energy in the rotor. The electric energy is generated through 
electromagnetic induction from the magnetic field of the stator windings. Within an ACIM, the rotor usually rotates at a lesser speed permanent magnet synchronous motor compared to the magnetic field. A “PMSM”, which stands for “permanent magnet synchronous motor”, relies on magnets to turn the rotor, which spins at the same rate as the PMSM’s internal rotating magnetic field.
There are some key differences between AC induction Motors and Permanent Magnet Synchronous Motors.