100,000 euros for research: “Future Technology Award” for Prof. Stephan Tremmel

Promotion of innovative research ideas at the University of Bayreuth

Schaeffler FAG Foundation as a motor for knowledge transfer

The foundation has been promoting science, research and teaching in the field of storage technology for over 35 years

The “Future Technology Award” of the Schaeffler FAG Foundation, endowed with 100,000 euros, goes to Professor Stephan Tremmel from the University of Bayreuth. Tremmel and his team are researching methods for safely diverting electrical currents from rolling bearings. The foundation presented the award for the first time in 2021.

Regardless of the design: Rolling bearings are essential components in all systems in which something rotates: It is impossible to imagine gears for wind turbines or a wide variety of mobility applications without them. However, the increasing electrification of many applications is leading to new challenges. One of them: so-called parasitic electrical voltages, which lead to misdirected currents. They can damage a wide variety of components - including rolling bearings.

The Schaeffler FAG Foundation is now supporting a research idea at the University of Bayreuth with the 100,000 euros awarded as part of the “Future Technology Award”. Here Professor Dr.-Ing. Stephan Tremmel found new ways to protect rolling bearings from this phenomenon.

“We see a highly innovative research approach in this idea,” says Andreas Hamann, Chairman of the Foundation Board and Head of Human Resources Europe at Schaeffler. We have created the Future Technology Award precisely for such projects, the real feasibility of which can only be tested under very high risk and unclear prospects of success. "

Unbalanced converters create parasitic currents

“Increasingly, parasitic potentials arise from higher switching frequencies in converters in connection with cheap power electronic components installed there,” says Professor Stephan Tremmel. These converters convert AC voltage into an AC voltage that differs in frequency and amplitude. They are needed, for example, to control and regulate variable-speed electric motors.

These parasitic potentials also end up in the mechanical drive train. “If they are big enough, they discharge and lead to discharge currents - which is very often the case in rolling bearings,” says Tremmel and explains: “You can imagine it like small flashes - arcs - across the lubricant that gradually after damaging the surface of the rolling elements. " This "electrical erosion" can then lead, among other things, to undesirable vibrations, an increase in temperature or even to premature failure.

Currently, bearings with ceramic rolling elements are used or bearings are provided with thermal spray coatings, which are then intended to ensure electrical insulation. However, these bearings are very expensive compared to conventional ones and are therefore not suitable for every application.

Promote a creative idea

So far, brushes in ring form or sliding contacts, which are attached to the rotating shaft, have therefore often been used to divert currents in a controlled manner. However, this does not work reliably because of the wear and tear when the speeds become higher. However, since the speeds of electric or hybrid drives increase for reasons of lightweight construction and energy efficiency, a different solution is required here. In addition, the sliding contacts generate additional friction. “We asked ourselves the question: How can we avoid these disadvantages?” Says Tremmel.

The basic idea: current discharge via a metallic solid-state contact works very well at standstill and at low speeds. In process or precision engineering, there are so-called liquid ring seals. With these, a liquid is thrown outwards by centrifugal force at high speeds and then seals a shaft, for example. “We want to make use of this principle,” says Tremmel, who does not want to go into any further details about the implementation as he is still at the beginning of his project.

Research at the University of Bayreuth

Stephan Tremmel is working on this at his Chair for Design and CAD at the Faculty of Engineering at the University of Bayreuth. "I am very pleased that the Schaeffler FAG Foundation sees such great innovation potential in the idea that it supports our work with the Future Technology Award," says Tremmel. With the funding of 100,000 euros, the idea can now be promoted and concretized.

In detail, this means that further calculations and simulations are made. Tremmel has already put together a team at the chair for this purpose. "This is followed by the implementation in prototypes and in a further step these are put to the test for different test procedures," says the engineer.

About the Schaeffler FAG Foundation:

The Schaeffler FAG Foundation promotes science, research and teaching in the scientific and technical field