The development and use of cranes in the market are becoming more and more extensive. Nowadays, many projects require the use of lifting equipment: machinery, metallurgy, chemical industry, mining, forestry and other enterprises and common in human life. Lifting equipment has Repeated working methods, multi-action hoisting machinery that can lift and transport heavy objects vertically within a certain range through the hook, can replace manpower vigorously, and can smoothly complete lifting and horizontal movements.

Cranes have the following categories: Lifting equipment can be divided into many types: truck cranes, cantilever cranes, cranes, gantry cranes, tower cranes and so on. Many equipment in cranes need to use slip rings to play the role of transmission. For example, truck-mounted cranes, slip rings need to transmit power power, throttle control signals, light signals, and some lifting equipment also require a range of rotation angles. Usually the power line current is 30A to 40A, we use 2.5mm2 and 4mm2 wires; the signal transmitted needs a special signal line; when the angle is limited, it needs to be controlled by an angle sensor.

The rapid development of my country's crane industry. Among them, the application of slip rings is becoming more and more extensive, and the requirements are getting higher and higher. There are also requirements on the protection level, wire size, bellows material, and service life. The slip ring is a very critical part of the crane, and the selection of the slip ring also needs to be very cautious.