Slip ring is an electromechanical device for signal and power transmission between the stationary parts and the rotator structure, also known as collector ring, rotary electrical interface. Such devices in industrial automation, medical equipment and defense aviation and other fields have a wide range of applications.

Slip ring consists of two main parts, conductive rings and the brush filaments, both contacts include point of contact and surface contact. Slip ring contact resistance will directly affect the results of signal transmission. In general, contact resistance as small as possible. Factors affecting the size of the contact resistance of the contact portion, in addition to the material, the contact in the form of the contact surface, further comprising a pressure wire brush on the slip rings. The higher the pressure the smaller the contact resistance, however, increasing the pressure of a certain limit, if it exceeds the limit will increase the friction torque, the contact part of the wear large. Slip ring generally use the number of revolutions as a measure of its life, the highest slip ring life is about tens of millions turn, if the application in high-speed rotating occasions, life is limited. Slip rings feature requires periodic testing its performance to ensure the reliable that the actual use of slip rings.

The main parameters of slip ring include dimensions, static contact resistance, dynamic contact resistance, insulation resistance, dielectric strength and friction torque and the like. In addition to these parameters in the manufacturing process of the system test, in the actual use, slip ring operating performance generally is judged by a simple test contact resistance, the test results can not available upon application directly evaluation slip ring signal transmission performance.

For the current detection methods imperfect under field environment for slip ring signal transmission performance, Cosmau company provided a method to test slip ring signal transmission performance, a method using a bit error rate test box is connected at both ends of the conductive slip ring, in selected under the communication interface and the baud rate, the test slip ring channel static and dynamic signal transmission error rate, as a method for testing slip ring signal transmission performance. Product test is essential for the quality of slip ring, only pass these test procedure, to be able to sell to the customer.