Slip ring

The slip ring is a component of Electromechanics and, together with the so-called brush sliding contact. It enables a power or signal transmission from a fixed to a rotating object.

General

As a slip ring material, various materials are used. The most important include brass, bronze, stainless steel, precious metals and coal, also sintered materials are possible. While the metallic slip rings are primarily suitable for high- power transmission, provide the carbon-based slip rings advantages in the transmission of small electrical performance. They are less prone to wear and resistant. This is further increased by gold. In addition to the general requirements, such as low wear and contact quality, the actual operating conditions and required transmission services for the design play a major role.

Applications

Slip rings are found in many electrical machines: In the small, they serve to signal and energy transmission as in radar systems, medical technology (eg computed tomography). The spectrum extends up to the transmission of high electrical currents and voltages. In the electroplating industry to flow up to 20,000 amperes over the sliding contacts for example in the chromium-plating or zinc plating of surfaces. At these high transmission powers are extreme conditions: The bathrooms are strongly acidic or basic, and the reactions take place at elevated temperatures.

Similarly harsh conditions posed by wind turbines, where the slip rings are exposed in part to strong vibrations. Despite this, collector ring systems required to maintain reliable contact. In addition, a risk of receiving a corrosive salt air; This is now prevented usually at the most vulnerable offshore installations through the use of positive pressure air-conditioned or hermetically sealed engine nacelles.

Particular difficulties arise in slip rings in space applications (eg actuators for solar boom ) by the vacuum, the large temperature range and the high reliability requirements. Additionally you'll find slip rings in electromagnetic clutches. These supply the coil with power and allow the switching.

Complex slip ring systems are also referred to as a " slip ring transmission " or " slip ring body."

Alternatives

All slip ring systems have the problem of consistently reliable electrical contact, together with all other sliding contacts, such as the contact wire.

Inductive coupler (practically a transformer on the rotation axis ) can be used for power transmission. Since the magnetic circuit is not optimal, the transmitted power is limited. Their main use is the supply of rotating battery-less sensors.

For signal transmission, wireless systems are preferably used by radio or infrared. This requires ( by today's standards ) analog - to-digital converter on the DUT. Also, the above-mentioned inductive couplers can be used for signal transmission by means of the directional coupler in the time or frequency division multiplexing method or.