Use of Ball Bearings as the Electrical Rotary Conductive Medium between the Fixed and Rotating Sections of a Product Assembly



Transmission between a rotating sensor and a non-rotating signal processing apparatus. Specifically rotating naval sensors.




As part of testing new products like Multi-functional Chartplotter / Radar and Fishfinders, there

was a requirement that compass calibration and wind transducer compatibility tests should be

performed via a new product. Compass calibration involved the vessel rotating through at least 2

rotations at a controlled speed. Wind transducer tests required the heading of the vessel to

change whilst the wind direction and speed remained constant. In the laboratory, these tests are

difficult and tedious, requiring the compass and wind transducer to be rotated by hand at the

same time as a fixed fan being used to emulate the wind.


The problem with testing on the water is that it is time consuming and that the sea trial time could be better used.



The requirement was to design and build a device that rotates any compass and wind transducer

through ideally an infinite number of rotations, in either direction, at a variety of speeds, in an

outdoor location. The device would be able to support at least two instruments and would have

data feedback from the instruments to the laboratory. This was accomplished using

bearings as a rotary conductive medium. Another design described in detail in the working file

was made up of a series of conductive rings each larger than the one before and each insulated from another. Holes on the bottom fixed section would allow wires to connect to each of the conductive rings. Holes on the top plate would do the same but here the wires would connect to brushes that slide on the conductive rings as the table rotates.

I150313FL01 Publication