crane slipring

In modern crane slip ring technology, slip rings and cranes are two of the most crucial pieces of machinery which are almost inseparable.

Slip rings are nothing but interlinking electrical devices which provide connectivity between stationery and a revolving system. They are also called electrical rotary joints, rotating electrical connectors, or electrical swivels.

They’re highly used at times when power or electrical signals need to be transmitted while rotating. However, they are also utilised in many types of machinery like cranes to improve their efficiency and performance.

As cranes are heavy-duty machines with moving parts like grabs and jib arms that need reliable power and data transmission for lifting and lowering material.

It requires crane slip rings to help with the movement, especially when a drag chain would get in the way or when it needs to turn more than 360 degrees.

How Does the Slip Ring Work

Components of Slip Rings

Metal rings and brush contact are the two main integral parts of slip rings. Common slip rings include capsule slip ring, Pin slip rings, USB slip rings, high speed slip rings.

a. Metal Rings

The circuit path is made by the ring, which is made of an electrically conductive material like metal, brass, silver plating, or coin silver. The ring is usually attached to a centre shaft but is insulated from it.

Between the rings and the shaft, there is insulation made of nylon, phenolic plastic, or another material that is a bad conductor of electricity.

The number of rings and brushes is decided based on the application and design of the machine.

b. Brushes

Brush arms are attached to side posts that ride on the ring to create electrical contact between the revolving and stationary portions of the unit.

They consist of graphite or phosphor bronze. Whereas, graphite is an inexpensive alternative whereas phosphor bronze provides superior conductivity and better wear life.

Arrangements and Electrical Current Transmission

  • Depending on the RPM (turns per minute), either the brushes are fixed and the rings turn, or the rings turn and the brushes are fixed.
  • In both of these designs, the springs push on the brushes to keep them in contact with the ring.
  • Most of the time, rings are attached to the rotor and turn which are made up of metallic and non-metallic materials, while brushes are fixed to the brush house and don’t move. Moreover, a set of ball bearing inside the housing supports the rotor.
  • Rings are made of metals that conduct electricity, like brass and silver. They are mounted on a shaft, but the centre shaft keeps the two parts from touching.
  • Nylon or plastic keeps the rings from touching each other.
  • The electrical current flows through the brushes as the rings turn.
  • This keeps the connection between the rings (the rotating system) and the brushes going all the time (fixed system).
  • The most important thing to note in slip rings working is that temperature, power, weight, size, and cost are the most pivotal factors in material choice. As, the electrical components discussed here are typically made of highly conductive materials for a variety of reasons, including voltage, current density, resistance changes, rotation speed, bandwidth, and so on.

How to Use Slip Rings in Cranes

Crane slip rings are significant in crane technology as they enable power and data transfer under heavy-duty situations.

The use of slip ring cranes in crane operation guarantees dependability, efficiency, and flexibility. The following are some examples of crane slip rings in crane technology:

Durability and Smooth Operation

The use of Rotar X crane slip rings with gold wire technology in crane systems provides longevity and trouble-free operation.


Crane slip rings give optimum flexibility for a wide range of crane technology applications.

Low Beginning Current and High Torque

Crane slip rings create strong torque while requiring little current at the start, making them an excellent choice for crane applications.

Operating well and Efficiently Under Extreme Conditions

Even in difficult conditions, the crane slip ring assembly maintains effective and efficient operation.

Rotation Speed is Controllable and Adjustable

The crane slip ring allows you to simply regulate and alter the speed of the crane rotation.

Reduced Full Load Current Demand

A crane slip ring induction motor requires 250% to 350% of the full load current approx., whereas a squirrel cage induction motor requires 600% to 700%.

Frequently Asked Questions

What is a Slip Ring and Why is It Used

Slip rings are electromechanical devices that allow electrical power and signals to be sent from a fixed point to a rotating object. They are used to simplify system operation or increase mechanical performance.

What is the Main Advantage of Slip Rings

Slip rings are very important because they let a machine or device turn while keeping an electrical connection. This means that there is no need for a fixed-length cable that would get twisted or tangled as the machine or device turned.

What Are the Advantages of Using Slip Rings on Cranes

When crane slip rings are used, power and data can be sent quickly and reliably between the stationary control system and the moving parts of the crane. Slip rings also give the crane the most flexibility and the ability to control and change how fast it turns.

What Types of Slip Rings Are Commonly Used on Cranes

Gold wire technology slip rings, like the Rotar X, are the most common type of slip ring used on cranes. These crane slip rings are made to last and work without problems in heavy-duty situations.

What Are Slip Rings Made Of

Slip rings are often formed of conductive metals like brass and silver, with graphite or phosphor bronze brushes.

What Are the Maintenance Requirements for Slip Rings on Cranes

Slip rings on cranes must be serviced regularly to guarantee maximum operation. This involves inspecting, cleaning, and lubricating the slip rings and brushes regularly to avoid wear and guarantee dependable operation.

Crane slip rings and their usage on cranes in the field of heavy machinery are profound. Their specific application usage, especially with hydraulic rotary unions and fibre optic rotary joints (FORJs) ensures that power and data are sent without any problems in the crane technology.

The advent of crane slip rings has changed the crane industry by making it possible to use cranes indoors and outdoors safely and efficiently.

However, crane slip rings require regular maintenance to guarantee maximum performance, but with appropriate care and upkeep, they may provide years of dependable service in the same.