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Rotary Joints

Ethernet – Contactless Data & Power Transmission (NEW)

Ethernet is used as a standard interface for data transmission and SPINNER has developed a contactless coupler (also referred to as a module) that can be provided with different inner diameters.

In contrast to transmission by means of a traditional slip ring, the Ethernet module also supports Gigabit Ethernet irrespective of the dimensions, while the correct standard is detected and transmitted automatically (10 Base-T (10 Mbit/s) or Fast Ethernet (100 Mbit/s) or Gigabit Ethernet (1 Gbit/s) – i.e. Plug and Play.

The mechanical system has been designed in such a way that one or two transmission modules can be incorporated, also in combination with the DC/DC converter described below. The converter has been designed so that more than 50 watts with 24 V output voltage are still available to the user in addition to the rotor’s own power supply.

Without requiring any adjustments, the data transmitter is fully compatible with Profinet (class A + B); a version with CAN bus (repeater mode up to 500 Kbit/s) is also available.

Our contactless power transmission system is a rotationally symmetric system for contactless transmission of electrical energy. This transmission system is used for the DC voltage supply of control systems, sensors or other consumers on rotating shafts.

The functioning of the transmission system corresponds to that of a galvanically isolated DC voltage transmitter. It keeps the output voltage nearly constant regardless of the load and over a wide input voltage range. The output has a short-circuit-proof and open-circuit-proof design. A major advantage is the presence of a hollow shaft, which means that combinations with optical single-channel or multi-channel rotary joints are possible for data transmission. This DC/DC converter meets all standards common in the industry with respect to safety, interference immunity and emitted interference.

In the radar technology sector, the trend towards installing active components directly on the antenna is continuing. The radical reduction in cabling saves weight and increases the efficiency of the system. However, ever increasing amounts of data with high transmission rates also require demanding digital data transmission solutions. For radar rotary joints, this means that traditional HF modules for the different frequency bands are replaced by diverse media couplers, power current and signal transmission paths.
Transmission amplifiers, now installed on the
rotatable part of the radar antenna, require media couplers to create a cooling circuit in order to ensure cooling. Power current is traditionally supplied by means of a slip ring. The electrical signals to and from the active antenna equipment are no longer transmitted by a contacting slip ring but via a multi-channel fiber optical rotary joint or means of a contactless

Contactless Data & Power Transmission

Rotary Joints – SPINNER Group (Germany)

Rotary joints are needed wherever high-frequency signals have to be transmitted between a fixed platform and a second platform in continuous rotation. Such applications include traditional radar technology for air traffic control or anti-missile defence, medical engineering, V-Sat and SatCom technology as well as TV camera systems or cable drums that allow sensitive cables to be wound up without twisting them, thus increasing their reliability.

In principle this can be achieved by three different technologies which mainly depend on the frequency of the transmitted signals:Rotary_Joint_1

    Contacting transmission by slip rings
    Depending on the unit size such contacting systems can transmit signals from
    DC up to 120 MHz.
    Coaxial contacting rotary joints
    These SPINNER products allow signal transmission in the frequency range from
    DC up to 50 GHz.
    Contact-free rotary joints
    Such extremely long-lived rotary joints are available as coaxial and waveguide
    units. The maximum signal transmission bandwidth is about 20% of the upper
    frequency to be transmitted.

The Spinner Company further offers:

    Rotary joints for optical signal transmission
    These can transmit up to 21 channels, as well as combinations of the individual types listed above in one rotary joint.

The special benefits of SPINNER rotary joints include their compact design, excellent VSWR and low attenuation loss, low variation of transmission properties during rotation, and high crosstalk attenuation between the individual channels over the whole frequency range.

With over 60 years of experience in RF technology SPINNER is in a position to develop and deliver any kind of rotary joint combination you may need.