Permanent magnet synchronous motors are highly efficient electric motors for a wide range of applications. As the name suggests, this motor technology requires magnetic material in the rotor. A basic distinction is made here depending on the position of the magnets (internal or external). However, with both types, the magnetic material belongs to the rare earths and they are therefore subject to limited raw material availability or dependence on the supplier countries/producing countries. This is just one of the things that also makes this type of motor relatively expensive, so that the purchase price is significantly higher than that of an induction machine. All the more reason then to get the most out of them with the right variable frequency drive. As a rule, IPMSMs are used in high-efficiency applications, if, for example, fans and pumps are to be operated in the IE4 or IE5 range. For applications where induction motors can no longer be used due to limitations in their efficiency range.