Ein Permanentmagnet-Synchronmotor mit schematischer Darstellung des Innenlebens
Motor technologies: Permanent magnet synchronous motor

Permanent magnet synchronous motors: flexible, energy-efficient and powerful

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.

Schematische Darstellung vom Innenleben eines Permanentmagnet-Synchronmotors mit innenliegenden Magneten

Permanent magnet synchronous motors with internal magnets: Maximum energy efficiency


The permanent magnet synchronous motor with internal magnets (IPMSM) is the ideal motor for traction applications where the maximum torque does not occur at maximum speed. This type of motor is used in applications that require high dynamics and overload capacity. And it is also the perfect choice if you want to operate fans or pumps in the IE4 and IE5 range. The high purchase costs are usually recouped through energy savings over the run time, provided that you operate it with the right variable frequency drive.

Our motor-mounted variable frequency drives use an integrated control strategy based on MTPA (Maximum Torque per Ampere). This allows you to operate your permanent magnet synchronous motors with maximum energy efficiency. The overload of 200 %, the excellent starting torque and the extended speed control range also allow you to fully exploit the motor rating. For a fast recovery of costs and the most efficient control processes.

Permanent magnet synchronous motors with external magnets for classic servo applications

Schematische Darstellung vom Innenleben eines Permanentmagnet-Synchronmotors mit außenliegenden Magneten

Permanent magnet synchronous motors with external magnets (SPMSM) are ideal motors when you need high overloads and rapid acceleration, for example in classic servo applications. The elongated design also results in low mass inertia and can be optimally installed. However, one disadvantage of the system consisting of SPMSM and variable frequency drive is the costs associated with it, as expensive plug technology and high-quality encoders are often used.

KOSTAL INVEOR variable frequency drives give you the opportunity to reduce your expenditure on permanent magnet synchronous motors with external magnets, because the smart technology of the INVEOR drive controllers means you can dispense with the costly encoders. So you get efficient SPMSM performance for your servo technology – at the best purchase price.


Our variable frequency drives for use with permanent magnet synchronous motors 

Motormontierter Frequenzumrichter KOSTAL INVEOR M auf Drehstrommotor


Our particularly robust motor-mounted frequency inverter with up to 22 kW. Supports motors up to IE4 and offers extra features for almost all your requirements.

Motormontierter Frequenzumrichter KOSTAL INVEOR MP auf Drehstrommotor


Our motor-mounted Performance flagship with multi-pump operation and IP 65 protection class. Available in four sizes up to 30 kW and for a wide range of motors.

Ein KOSTAL INVEOR MP Modular Frequenzumrichter der Performance-Serie auf einem Elektromotor Dateiname: kostal-inveor-mp-modular-frequenzumrichter


Our modular variable frequency drives with smart power stack or the option of integrating your own application boards and electronics. Available in four sizes with up to 30 kW.

Do you have any questions about using KOSTAL variable frequency drives with permanent magnet synchronous motors?

Then complete our contact form or give us a call. We will answer your questions and help you to implement the right solution in your company.

KOSTAL support for new and potential customers

KOSTAL Industrie Elektrik GmbH & Co. KG / Business Unit Drives
Lange Eck 11
58099 Hagen, Germany

Telephone: +49 2331 8040 - 468
E-mail: sales-industrial@kostal.com

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