What is Electrical Slip Ring? Principle, Types, Advantages, Applications

Electrical Slip Ring is one of the types of conductive components of an electrical system.

This conductive component plays an integral role in transmitting power and signals (especially from the rotary to the stationary structure component).

The slip ring provides continuous transmission of power and signals while 360-degree rotation of the system. In any 360-degree rotation of system (or machinery), it is one of the best solutions to counter the twisting and tangling conditions. 

What is an Electrical Slip Ring?

The Electrical Slip Ring is an electromechanical device that transfers electrical energy across the moving interfaces.

As per its name, the slip ring is constructed by two main components as circular conductive (or metal) rings and brushes. Basically, the construction of a slip ring depends on the design of machines and appliances.

The slip ring works as an electric transmission device. So, it is also known as “Collector Ring” or “Commutator” or “Rotating Electrical Connector” or “Rotatory Electrical Joint” or “Electric Swivel” or “Rotary Electrical Interface”.

When it comes to the working operation of an electrical and electronic system, slip ring devices carry electrical current in the form of alternating current (AC) and direct current (DC).

The basic function of the slip ring is to provide the transmission of power and all kinds of precision signals to the connected systems for generating continuous rotation. Thus, it is very capable to improve mechanical rotating performance while transmitting electrical power or signal.

Components of Electrical Motor

Types of Electrical Slip Ring

There are different types of slip rings manufactured and designed for the transmission of data or power in liquid or gas mediums.

According to the construction and size, electrical slip rings are classified into different types as follows.

  • Pancake slip ring
  • Mercury wetted slip ring
  • Fiber optic slip ring
  • Wireless slip ring
  • Ethernet slip ring

Each slip ring can be explained one by one as follows.

Pancake Slip Ring

A pancake slip ring looks like a flat disc that consists of many conductive rings. These conductive rings are placed at the center of the rotating shaft.

Under this construction, pancake slip ring is also called a “Flat Slip Ring” or “Platter Slip Ring”.

The pancake slip ring is classified into two parts. One is the separate disc and another is an integral disc.

Both slip rings types have certain advantages. It emits low electrical noise, torque, and friction. It has a long life span too.

The pancake slip ring is mainly used to transmit precise signals along with power in a rotatory device. It is used in space-critical applications, rotating machinery, and other hydraulic and pneumatic applications.

Mercury Wetted Slip Ring

Mercury slip ring is basically known as “Mercury rotary joint”.

Mercury wetted slip ring is basically made by the mercury materials that work as conductive media. Thus, this mercury media provides the conductive component that allows the transmission of electric signals and data.

This type of slip ring has some advantages like providing high stability; create low noise anti-interference. It comes with very economical in cost.

One of the disadvantages of the Mercury wetted slip ring is that it requires more maintenance. So, it is rarely used in delicate sectors like the medical sector, pharmaceutical industries, and the food processing and manufacturing industries. It is mainly used in commercial applications.

Fiber Optic Slip Ring

In another word, fiber optic slip ring is also known as “Fiber Optic Joint” or “Fiber-Electric Rotary joint”.

The main function of a fiber optic slip ring is to pass signals across the interfaces when a large amount of data needs to transfer from one place to another.

It is used in different applications such as medical equipment (for example, CT scan and X-ray machines), radar application, video monitoring, and transmission system, microwave communication, sensor-based signal management system, etc.

Wireless Slip Ring

The wireless slip ring is operated wirelessly to transfer the electrical signal or transmission data. So, this type of slip ring does not require friction-based conductive (metal) rings and carbon brushes.

It basically works based on the electromagnetic principle. This electromagnetic field is produced by the magnetic coil which is placed between the rotating receiver and stationary transmitter.

The wireless slip ring is used in fiber optics, remote monitoring appliances, and other electronic devices.

Ethernet Slip Ring

Ethernet slip ring is based on the Ethernet communication protocol. It is used for communication purposes. It has the capability of emitting the communication obstacles (like occurring losses, impedance, controlling crosstalk, etc).

Mostly this Ethernet slip ring is used in HD video monitoring systems which can easily transfer HDTV communication signals.

Advantages of Slip Ring

  • Slip ring device finds in a compact size so that user can easily transport it.
  • In any electronic device, a slip ring can be easily installed and handled. For example, in an induction motor, a slip ring is used.
  • This device improves mechanical performance and provides an electrical connection through the rotating assembly.
  • The main advantage of the slip ring is to perform continuous rotation at 360 degrees that allow high-speed transmission of data or signals.

Applications of Slip Ring

Electrical slip ring device is used in different sectors from industrial to commercial environments.

It is used in the oil and gas industrial plants, medical and pharmaceutical sectors, aerospace, agriculture equipment, and other automatic rotating devices.

Let’s see few daily life applications of slip rings.

  • Slip ring is widely used in electromechanically devices such as electric machines (like as electric motor, alternator, and generator).
  • It is used in industrial machines like as induction motors, computer numerical machines, capping machines, pallet machines, rotatory sensors, packing machines, bottle labeling machines, and other heavy industrial equipment.
  • In the food and pharmaceutical sector, slip ring device is used in industrial machines for manufacturing, controlling, and packaging processes.
  • Drones or unmanned aerial vehicles (UAV) that helps to audit, record, and gather specific information (especially from aerial view) uses slip ring.
  • It is used in medical equipment like as CT scans, X-rays, advanced surgical robots, etc.
  • Military devices, magnetic driver’s radar, tanks, and other auto parts steering wheel devices uses slip ring.
  • Slip ring is utilized in video surveillance equipment such as CCTV cameras.


In this article, we have studied all the basic concepts of conductive components i.e. Slip Ring. Also, here we have learned about the different types of slip rings that are used in advanced technologies and smart industrial and commercial electronics appliances.

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2 thoughts on “What is Electrical Slip Ring? Principle, Types, Advantages, Applications”

  1. Description is very detail, I appreciate efforts of “Instrumentation Tools” for providing a gate way to knowledge sharing.

  2. Thank you for your help with the overview on slip rings. Now that you explained- I too can see that the slip ring serves as an electrical connection between the rotating and stationary components of a motor, to transmit a steady electrical signal, in the end, this new revelation about slip rings will benefit me when troubleshooting synchronous motor controls.

    R. W.


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