An Ultra-Fast Electric Motor for Satellites


Scientists from ETH Zurich have developed an ultra-fast electric motor for satellites. They have developed magnetically floating electric motor for reaction wheels. Its high speed allows intensive miniaturization of the drive system by making it impressive to use in a small satellite. This research was demonstrated by ETH researchers and their colleagues at Celerotron.

Generally, such type of electrically driven reaction wheels is used in satellites to change the attitude of the satellite. Through a shaft i.e., rotor the reaction wheels are connected to an electric motor. The flywheel driven by this motor revolves in one direction by taking very short time about its own axis. A twisted item then transformed to the satellite, which revolves in opposite direction to the flywheel. Thus, causes novel orientation.

This motor can run 20 times faster as compared to existing systems and has a small size and more energy efficient.

Discovery of This Ultra-Fast Electric Motor

The research begins before a few years ago. This type of motor can be operated at 150,000 rpm. That means it is faster as compare to existing models as the rotor floats in a magnetic field. Through ultra-high rotational speed, researchers get declined size of the drive system. This is because it transmits same angular momentum like large motor against its small dimensions. It actually makes it more impressive to be used in small satellites with a size similar to a shoe box.

Components of the reaction wheel motor and their assemblage. (Photo from Zwyssig et al., 2014)
Components of the reaction wheel motor and their assemblage. (Photo from Zwyssig et al., 2014)

The rotors and reaction wheels are firmly fixed on ball bearings that drain fastly. Such type of motors is generally operated below 6,000 revolutions per minute to minimize mechanical wear. It is necessary to keep them under secret closed covering in a low-pressure nitrogen atmosphere. It is done to avoid material’s oxidization and lubricant vaporization.

Additionally, the ball bearings are also not identical, increase forces that together with the imbalance of the rotor transfer micro-vibrations to the satellite’s housing. This minimizes accuracy in a position which satellites must exhibit in order to allow, for example, laser measurement or inter-satellite communication.

These are the major drawbacks in current systems. To overcome this drawback, scientists developed this ultra-fast electric motor. Although this new system developed by scientists is complex, some complex power electronics are essential to run and control it.

Arda Tüysüz, a postdoc at ETH Zurich’s Power Electronic Systems Laboratory (PES), said, “There is actually nothing new about it. Magnetic bearings, electronics and the basic principle was already there.”

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