A slip ring is one of the many electromechanical devices, that is, a device that has both electrical and mechanical processes. Just like pressing switch manually results in current flow, a slip ring features both electrical and manual or mechanical movements. A slip ring is designed to transmit signals, electricity or data, from a stationary component to a rotating part. They are popular in electric motors and other electromechanical equipment. Because of their unique role, slip rings come in various types and specifications for the application. Here is a brief overview of slip ring functions, including insights on existing brands and how to find the right model for your needs.

What are slip rings used for?

Slip rings come in many forms and specifications, depending on their unique applications. However, all slip rings play the same central function, only in different equipment and applications. These electromechanical devices are primarily designed for the following applications:

1. Transmitting power

All slip rings were initially designed to transfer electric current from a stationary to a rotating component. The design of a slip ring features two main parts, which are the carbon-graphite brushes and metal alloy rings. The stationary brushes are manufactured using fiber technology and might feature precious metal coating to reduce corrosion. The rotating ring can be made from different metal alloys depending on the application or machinery where the device is installed.

2. Transmitting data signals

Slip rings became essential devices in the transfer of data signals and packets between rotating components. This is particularly efficient in factory models where large amounts of data are required to flow from stationary elements to moving parts. Slip rings designed for data transmission also transfer power since data cannot be transferred without power. However, not all electric slip rings can transmit data. A USB slip ring is one standard model for data transmission and there are several models built for this purpose.

3. Data and power transmissions

You can find hybrid slip rings designed for applications that require transmitting both power and data signals to rotating components. These specialized slip rings feature disparate circuits for data and power to ensure minimal noise and interference. It is essential to review all specifications before choosing hybrid slip rings, or any other model.

What are the types of slip rings?

While the function of a slip ring is the same regardless of the application and type, its functioning heavily relies upon the unique specifications. When selecting slip rings, you will come across several brands and vendors offering different standard and custom models. Some of the popular slip rings in the market include:

1. Through bore slip rings

Also known as through-hole slip rings, these devices feature a space at the center of the design. The hollow shaft in the design offers a path for wires and circuits. Its model also allows conduction materials to join on the exterior surface that features metallic rings and dimension plates. This reduces tangling and the hollow shaft can also connect the rotating component to the rotor. You can find through bore slip rings varying bore diameter sizes, from 3mm to 300mm.

2. Pancake  slip rings

Pancake slip rings get their name from the disc (pancake-like) design of the device. These devices suit applications that have limited vertical space and a wider horizontal gap. They are common in miniature systems such as smart toys, where they feature PCB for the surface material. Because of their thin lightweight design, pancake slip rings aren’t recommendable for extreme or harsh operating environments. They feature varying electrical and mechanical specifications, although most pancake slip rings can carry 2 to 48 circuits.

3. PCB, Fiber Optic and USB slip rings

PCB (printed circuit board) slip rings offer a thin, lightweight, durable option for miniature systems and applications that require small low volume devices. Fiber Optic slip rings, on the other hand, carry the intrinsic benefits of fiber technology and is ideal for data transmission slip rings. USB slip rings are also perfect for data transmission, although they are generally designed for all USB signals. These slip rings are common types you will come across and feature individual specifications to suit different applications.

4. Rotor and Stator Flange slip rings

Rotor slip rings get their name from the unique design that features a flange on the rotor. This slip ring suits industrial applications but can also be used in non-industrial operations. A stator flange slip ring, on the other hand, is prevalent in miniature systems. Instead of installing the flange directly on the rotor using anti rotor pole mounts, it is located on the exterior surface of the rotating metal alloy or rings. The rotating component is also separate from the cable, unlike in all other slip rings where it is fixed to the cable.

5. Pneumatic Hybrid slip rings

Pneumatic hybrid slip rings are installed in large, sophisticated machinery and experienced vendors or professionals often accomplish the installation. These slip rings are designed for industrial applications and require a special process to ensure proper alignment between the inner metal rings and brushes. Pneumatic slip rings are popular in automated welding equipment, downhole drills, offshore drilling rings , and conveyor processes among other industrial.

6. Multichannel FORJ slip rings

Multichannel fiber optic rotary joints are a special group of slip rings designed for datacom links and transmitting large amounts of data between rotating parts. They are slightly different from other single-channel fiber optic slip rings mentioned above because of the ultra high strength thermoplastic fiber. These devices allow transmission of optical signals through a fiber axis and provide several circuits or channels for bulk communications.


There are many types of slip ring designs and models beyond standard options. These devices are built to work in specific machinery and under given operating conditions. As such, it is essential to choose the proper model and specifications for your application. You should also purchase all slip rings from credible, reputable vendors that can guarantee premium quality devices. Slip rings have the sole function of transmitting various signals between stationary and moving parts. However, the purpose isn’t always limited, as they can function as joints and play other roles in the system.



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