The world of industry and electromechanics is always in motion. More precisely, in rotary motion (rotating consumers). Wind turbines, medical technology, crane technology, stage technology, video cameras, screens, data-driven automation, data transmission and robotics – standstill is the death of efficiency and innovation. None of these industries function without the transmission of power and data on continuous, unrestricted or intermittent rotation.

Therefore, reliable, maintenance-free and loss-free transmission of data, power and electrical signals between the individual stationary and rotating components is required. That’s were electromechanical devices come into play that allow that kind of transmission, regardless of the application or kind of rotation: slip rings. This may be components rotating incomplete revolutions in one direction continuously or rotating incomplete revolutions in either direction. Or they oscillate through parts of a revolution, depending on the application.

Slip rings are elementary for every industry in motion, such as:

• robotics
• medical technology
• agriculture
• food & beverage industry
• wind energy

To name just a few.

They do not only fulfill a purely technical function that cables could not perform in the transmission between two rotating or a stationary and rotating component. Slip rings also help to improve mechanical performance, simplify system operation, and eliminate the need for damage-prone cables hanging from moving joints. For a long time now, it has not only been about the transmission of electricity. Especially in the context of Industry 4.0, it is becoming increasingly important that slip rings can transmit much more and that under various requirements and a wide variety of rotation speeds. Our roots are in wind power, but over the last few decades we have been able to gain a lot of experience in transferring the requirements for space saving, reliability, speed, robustness and freedom from maintenance to other sectors.

Because it doesn’t matter whether it’s a human-robot collaboration, a filling system, factory automation, a sprinkler system, a rotary milking parlour or a CT device. They all require a combined transmission of signals such as Profinet, fieldbus, HD-SDI or video signals, data and power.

Since numerous mechanical components are always in rotation, which makes fixed power transmission or data transmission via cables impossible, slip rings are indispensable and almost maintenance-free and invisible electromechanical components. At the same time, slip ring assemblies and their sliding contacts are the heart of every automation system and machine, which, thanks to the brush (sliding contact), enables contactless power and signal transmission between stationary and moving components, or components rotating against each other, e.g. of video signals, Ethernet signals / Profinet, COAX, HD-SDI, fibre optic cables and field buses.

For this purpose, the slip ring assemblies must be manufactured according to your personal and industry-specific requirements and from the best materials, which enable fast, low-wear and loss-free transmission of data and power under a wide range of conditions and temperatures. Just like our slip ring assemblies and rotary unions from RotarX. As a manufacturer of slip rings, our focus is on the highest contact quality of the silver-to-silver and gold-to-gold sliding contacts and maximum life expectancy, while at the same time requiring the least amount of maintenance.

The ever faster and endlessly rotating data transmission of control signals, video signals and measurement data is becoming increasingly important. In addition to the standard current transmission, rotary joints for fluids (e.g., hydraulic fluid or oil), gases and compressed air complement the classic slip rings. We even offer hybrid combinations of rotary union and slip ring so that you can transmit data, power, electrical signals as well as liquids, gases or compressed air with just one component. We call them hybrid electrical and pneumatic rotary union that also include the transmission of liquids, emulsion and gases.

These are used, for example, in hydraulic chain excavators or for tire pressure control systems. With a tire pressure control system, they can not only transmit the compressed air, but also the measured values ​​of the current tire pressure. In an excavator with a revolving superstructure, the return oil and hydraulic fluid reciprocation under high pressure can be realized, but also, for example, the level of the hydraulic oil tank can be transmitted. In the field of wind energy, they are used for pitch control and YAW control. For example, not only electricity or hydraulic fluid has to be transmitted to adjust the blade angle, but also the data from the anemometer to adjust the blades of the wind turbine to the wind direction and wind speed using the pitch motors.

The fast and error-free transmission of all data for energy production and maintenance via fiber optics also plays a major role, especially for offshore systems. Because offshore wind turbines are monitored from land. And since maintenance work on such wind turbines is significantly more expensive than on land, this transmission must function smoothly in the truest sense of the word. In addition, the slip rings are exposed to the particularly harsh conditions of salt water, which is why special know-how is required here.

What many people don’t know: slip rings in wind turbines are also used for lightning protection. The slip ring connects the rotating parts of the turbine to the stationary earthing system. Wouldn’t that be the case a flashover or arcing would occur if the rotor blades were stuck by lightning. That could lead to bearing damage due to welded joints in components that are rotating relative to one another.

The three main parts of a slip ring assembly (SRA):

1. A rotating part with conductive rings separated by insulation material: Common slip rings conductive rings planes are arranged parallel to each other. They form a cylinder. But some slip ring assemblies have concentrically arranged rings in the same plane (they are called pancake slip rings). Pancake slip rings are the perfect solution for minimum installation heights. Vertically arranged rings and pickups enable use wherever the installation space in the direction of the longitudinal axis is limited.
2. Stationary brushed of the strator: Put simply, data, power and signals are transmitted by the friction of the brush of the slip ring on the component. The materials selected for the brush contacts vary depending on the specific application. We rely on brush technology with low electrical noise, for the transmission of fieldbuses with high data rates, low contact pressure for a long service life and freedom from maintenance.
3. The customers needs: For example, you can choose between fiber brush and fiber brush technology, different materials such as aluminum and plastic, and precious metal contacts such as the silver-on-silver and gold-on-gold multi-contact. We are aware of the growing importance of reliable and maintenance-free signal and energy transmission in the context of Industry 4.0. In the future, almost every component will no longer only fulfill a mechanical function but must also be able to transmit data and other signals.