through-hole slip ring

A through-hole slip ring design is one of the common examples you will find when searching for functional rotary joints for your device. Slip rings are electromechanical devices provided to facilitate the communication of power, data, and other signals between stationary components (stator) and rotating parts (rotor).

Primarily, these devices function in systems that feature shafts making infinite 360° rotations, where wires are impractical. However, each slip ring is different and features unique specifications optimized for the equipment where it is installed and the operating environment. Through-hole slip rings feature a hollow space at the center to allow the shaft to rotate freely. Space also offers room for channel wires and circuits.

Concerning the design, through-hole slip rings feature a stationary and rotating element, just like most rotary joints. The design may feature fixed brushes that slide against the rotating shaft or a fixed shaft with a rotating housing that contains fixed brushes. It all depends on the application and equipment.

How Does a Through-hole Slip Ring Work?

Through-hole slip rings retain the functionality of standard rotary joints, which is to transmit signals from a stationary (fixed) component to a rotating element. In standard through-hole slip rings, the fixed part is made using carbon graphite and fiber brush technology. They are also referred to as brushes. The rotating metal rings are made from a wide variety of durable metal alloys.

Contact surfaces may also feature precious metal plating. The through-hole slip ring works by communicating both power and data signals from the static part to the rotating piece of the machinery. This functionality is replicated in a wide variety of electromechanical rotary joints used in different applications and systems.

Applications of Through-hole Slip Rings

All slip rings are designed to transmit various types of signals between the stator and rotor parts of the system. However, the equipment and application environment will dictate the necessary specifications. Through-hole slip rings feature a space at the center where the rotating shaft passes. Some of the popular applications of these rotary joints include:

1. Loading and Unloading Power Plants

Through bore, slip rings used in loading and unloading come in stackers that can withstand the heavy mass the machine is meant to lift. The application requires high-voltage slip rings with precise specifications for the operating environment. Power plants, such as loading and unloading equipment used at ports, rely on the functionality of through-hole slip rings to communicate power and data signals.

2. Heavy Motors

Heavy motors, such as those used in the cement industry and mining projects, require through-hole slip rings to facilitate efficient power and data transmission between static and rotating components of the plant. Through bore slip, rings boast a sturdy design and can feature premium strength materials and plating to ensure maximum durability. Most large motor rotary joints are through the bore.

3. Electric Generators

High-voltage electric generators use bore slip rings, which can accommodate the enhanced specifications required for such applications. Several types of electric generators require high voltage and initial torque. Through bore slip rings can insert the necessary resistance in addition to communicating signals. They can also feature a single channel or multiple channels, depending on the application.

4. Wind Technology

Wind turbines and windmills use electric generators that feature through hole slip rings. Most turbines and wind technology systems use various slip ring combinations, so you will find both through bore and pancake slip rings in different parts of the machinery. The through-hole slip ring used for wind technology is optimized for the outdoor operating environment and all its wear elements.

5. Offshore Cranes

Like wind technology systems, offshore cranes use a combination of different slip rings to achieve their functions. High voltage through bore slip rings are virtually inseparable from these systems and accomplish the transmission of power and data signals through rotating joints. There are various specifications, depending on the type of crane and installation requirements.

Through-hole Slip Ring Usage and Maintenance

There are several other uses of through-hole slip rings other than the ones mentioned above. If you are looking for new through-bore slip rings to replace old or damaged devices, you can find exact specifications or compare other replacement models with better features. Manufacturers usually provide new models with better properties and capabilities, so it is always recommended to research better options before replacing your slip ring. On the other hand, if you want slip rings for new installations, make sure you note down all specifications in the instructions sent to the manufacturer or vendor. Here are some insights for using a through-hole slip ring.

1. Choose Models for Your Application

It is of paramount importance to identify all the unique specifications needed for proper functioning through bore slip rings. You should inform the manufacturer about all crucial details, including the type of equipment, dimensions, properties, and operating environment. For instance, if the slip ring is intended for outdoor wind turbines, they should be weatherproof. Similarly, those in blast environments should be insulated from the excess heat. Size, thickness, rotation per minute, and strength are all crucial specifications, so make sure the manufacturer understands the instructions.

2. Achieve a Clean and Neat Installation

You should follow the installation procedure specified by the slip ring manufacturer to make sure the installation is neat and clean. Proper installation will ensure top performance, which is essential when using high-voltage rotary joints. As such, you should entrust through hole slip ring installation to experienced professionals who can guarantee high-quality services.

3. Monitor the Slip Rings

As electromechanical devices, through bore slip rings will eventually get old and worn out, calling for a replacement. Monitoring how you use the slip ring will help you catch degradation early and can prevent costly replacements. It also identifies strains in the system and can provide data to help you plan for maintenance or servicing. Heavy-duty slip rings will probably require lubrication at some point and monitoring the system is part of the maintenance needed for such systems.


A through-hole slip ring features a hollow space at the center of the design, which is its primary distinction from other slip rings. It also supports high-voltage channels and offers maximum durability. You can find standard models from popular brands like Senring, Moflon, JINPAT, and Rotarx. However, make sure you customize the order to get slip rings tailored to your unique needs.


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