compacore, the innovation for efficient electric motors 4 minutes spent reading

compacore, the innovation for efficient electric motors

Volkmar Held
As a freelance writer, Volkmar Held reports for voestalpine on topics that move people. The content of his stories ranges from archaeometallurgy to future technologies.

With its compacore® inline-bonded lamination stacks, voestalpine offers the automotive industry the optimal technology for the heart of electromobility: the motor. compacore® makes it possible to produce innovative powerhouse lamination stacks that significantly improve the efficiency of electric motors.

With its compacore® innovation, voestalpine has developed a manufacturing method that is ideal for serial production of full-faced bonded stators and rotors. In a newly developed inline process, highest quality electrical steel, with a special self-bonding coating is bonded to form lamination stacks. This process avoids the interlaminar eddy current losses that result from other joining processes such as welding or punched stacking and improves the electromagnetic properties of the stacks.

Central locking, window regulators, wipers, stability programs, radiator fans, speedometers, exterior mirrors, seat adjustment—what do these car components have in common? Precisely, they are all working with electric lamination stacks. Over 100 of electric motors are at work in cars. And, of course, there are the powerful electric motors in all types of electric cars.

voestalpine compacore Motor

The driving heart

It contains specialized components that provide the necessary power—including highly efficient lamination stacks (compacore®) for the rotors and stators.

compacore® lamination stacks in a hybrid motor.

compacore® lamination stacks in a hybrid motor.

The stacks are made of thin electric steel layers that are bonded with a baked self-bonding varnish. This process minimizes unwanted, uncontrolled electromagnetic fields. Since the technology of the bonded rotor and stator stacks does not require welding points or clamps for bonding, the integrity of the insulating layer between the lamination layers is not compromised. This benefits the electromagnetic properties of the lamination stacks and gives designers greater creative freedom. Dimension accuracy of the components is a given.

"Automatic height control ensures that the dimensions of the lamination stacks are correct and can be installed as intended. Our unique inline electrical measurements ensure that the required parameters are met before the components are installed."
Karl Radlmayr, Metal Forming Division

The benefits at a glance:

  • Higher efficiency, greater vehicle range
  • Guaranteed, verifiable properties
  • More design freedom—smaller dimensions possible
  • Improved acoustics through full-faced bonding
  • Better thermal management—less cooling required

Read more on the compacore® microsite.

compacore®—the quiet powerhouse


compacore for efficient electric motors

Full-faced bonding of electrical steel layers offers even more benefits, especially for mobility applications. The mechanical power of the engine is accompanied by heat dissipation and typically more or less perceptible noise. Almost everyone is familiar with how an electric mixer heats up with use or has heard the humming of an approaching electric locomotive. If the layers in the stacks are not firmly bonded to each other, electromagnetic fields will cause them to vibrate and eventually generate audible sound waves: the motor hums. The “silent design” of the compacore® stacks bonds electrical steel layers over their full face with baking varnish, effectively preventing this. It also improves the efficiency of the motor, an effect that is especially noticeable in smaller motors such as those used in eBikes. That is why compacore® stacks are also used in these motors and—after final production tests under customer supervision—went into series production this past March.

Prototype construction increased tenfold

The construction of prototypes is an indicator of trend development. This is especially true in the electromobility sector. „We have ensured series reliability and are currently optimizing the process in order to be able to cover customer demand on time,“ comments Karl Radlmayr.


The production station for lamination stacks in Nagold.

The electrification of the powertrain is one of the most important future topics in the mobility market segment. This means the interdivisional voestalpine development compacore® has enormous potential.

Visit us at CWIEME 2019 in Berlin, May 21-23, 2019, Stand D21 in Hall 2.2.

Additional Material

Volkmar Held