Outstanding electromagnetic properties, low thicknesses ranging from 0.10 to 0.35 mm (0.004 to 0.014 in), and customized bonding systems for high-performance lamination stacks – our wide range of efficient electrical steel strip grades and coating systems covers all the requirements of state-of-the-art electrical applications.
Energy supply and mobility are the basic requirements of a functioning economy and society. Currently, these industries are undergoing a major transformation. This is due to the fact that one of the key demands is to significantly reduce carbon emissions. In addition to alternative energy sources, electric-powered vehicles are playing an increasingly important role in the automotive industry and are becoming attractive to a broader range of buyers, not least as a result of extensive government subsidies. In combination with electricity from renewable sources, electric and hybrid vehicles help reduce carbon emissions.
The standards that the required rotor and stator components must meet are correspondingly high. Maximum performance and efficiency are just as important as the consistently high quality of the electrical steel strip grades. In addition to the technological parameters relevant to the final product, our customers also value business factors such as processing properties and reliable availability.
Waelzholz offers high-performance electrical steel strip grades that fulfill these requirements and thus form a reliable material basis for the energy and mobility concepts of tomorrow.
Electrical steel strip in accordance with DIN EN 10303 for efficient drive systems – low core losses at high frequencies
The thickness of the electrical steel strip has a significant impact on the electric motor’s performance and efficiency, as core losses increase with the thickness of the material, especially at high frequencies. In electric drives for automobiles, NO20 to NO35 grades with strip thicknesses of 0.20 to 0.35 millimeters (0.008 to 0.014 in) have become the standard for technical and commercial reasons. For high-end applications, Waelzholz even offers customers its NO10 grade with a strip thickness of just 0.10 millimeters (0.004 in).
With our NO grades, customers have the ability to manufacture electric motors with long ranges. In addition, our thin electrical steel strip makes space-saving, compact electric motor designs possible. This represents a decisive advantage, particularly in hybrid vehicles, where there is only limited space available for the power unit in the engine compartment.
Producing thin electrical steel strip grades with reproducible properties is extremely demanding, however. At Waelzholz NO grades are manufactured on specially designed production lines. In this context, our process reliability is a skill that has evolved over the course of decades and is how we reliably maintain the electromagnetic parameters and dimensional tolerance of the geometric properties to within a few thousandths of a millimeter over countless delivered batches.
The precise dimensional tolerance of Waelzholz’s electrical steel strip grades ensures that our customers are able to reproduce the dimensional accuracy of their rotor and stator stacks with extreme precision. After all, even when a car’s electric drive system rotates at high frequencies of up to 20,000 rpm, it still needs to run perfectly smoothly. Such high frequencies require the electric steel strip to exhibit appropriate levels of yield strength – Waelzholz also offers its NO grades as high-strength versions precisely for this purpose. In this case, we can achieve yield strengths (Rp0.2) of more than 500 MPa with modified electromagnetic properties.
To create a disturbance-free bond between the electrical steel strip plates, the strip can be coated with bonding varnish or fast-bonding varnish. This prevents the “frequency hum” caused by welding, riveting, or stamping. In addition, in contrast to conventional joining techniques, the use of our bonding varnish systems has no negative impact on efficiency.
In addition to bonding varnish, our NO grades can also be combined with conventional insulating varnishes.