Soft magnetic material characterizations get a harder look

November 14, 2017, American Institute of Physics
An electrical machine, sliced open to show the rotor and stator iron lamination, which consists of soft magnetic material. Credit: Silas Elfgen

In motors, generators and similar electric machines, the electrical current that powers them generates magnetic fields that magnetize some of the metallic components.

Choosing the right magnetic material is crucial for designing efficient machines, so researchers from the Institute of Electrical Machines (IEM) at RWTH Aachen University in Germany analyzed the existing system for characterizing soft magnetic materials, which are easily magnetized. To identify a better system for quality control, they looked at several factors that can affect the inherent in the measurement of magnetic properties. Their results are published this week in the AIP Advances.

One example of a soft magnetic material manufacturers use to make generators, electric motors and transformers is low carbon steel. Generally, these materials serve the purpose of guiding and amplifying the magnetic flux when converting between mechanical and electrical energy in these . Magnetic measurements allow manufacturers to characterize those materials and to calculate how much power will be lost due to the magnetization process.

"Manufacturing processes such as the cutting of the steel lamination influence the behavior of the soft magnetic material," said Silas Elfgen of RWTH Aachen University. "Therefore such influence has to be measured and we must be able to model such parasitic effects."

Standardized methods for evaluating exist, but the researchers found them to be inadequate for applications such as designing traction drives in vehicles. They used one of the standard testing instruments, called a single sheet tester, to characterize soft magnetic across a range of frequencies and magnetic flux densities.

Their tests showed that the currently used parameters describing measurement qualities are not sufficient for accurately evaluating uncertainties that arise at frequencies and magnetization levels of some applications currently of interest. They also looked at additional factors that influence the characterization and measured how much each parameter contributes to the uncertainty. They propose that these uncertainties can guide the selection of the most appropriate soft magnetic material for a specific electrical machine.

"These analyses can be used by everyone working with magnetic characteristics and magnetic model parameters," Elfgen said. "Further, it can be used in quality assurance of a product to define production features."

Explore further: Characterization of soft magnetic nanocomposites

More information: "Characterisation of soft magnetic materials by measurement: Evaluation of uncertainties up to 1.8 T and 9 kHz," AIP Advances (2017). DOI: 10.1063/1.4993294

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2.3 / 5 (3) Nov 14, 2017

Look up Gabriel Kron.

You'll have a hard time finding his works (the more important works, that is), even though he was touted as the genius (for over 20 years...!) who solved all these motor problems, for the giant GE corporation.

It's almost as if....someone pulled all his works and references from the libraries. Governments and their deep state corporate partners are on record as committing these acts of data and reference removal during times of war, so when cold wars come along..this reduction of public information is not just likely but 100% assured to continue.

Dig deep........

You'll get to the first layer and then keep digging and reading until the light bulb goes on.
not rated yet Nov 15, 2017
"It's almost as if....someone pulled all his works and references from the libraries."
Diakoptics is still available on Amazon, as well as a book from L.V. Bewley 'Tensor Analysis of Electric Circuits and Machines'. He says in the introduction that it was a gathering together in one text all of the work on the subject that Kron had done up to the early 60's (I have Bewley's book that used to sit on a shelf at the U.S. Navy Postgraduate school in Monterey CA--Based on the cards at the back of the book, it was last checked out of the library in 1987, which explains why it was up for sale).

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