The electric swivel (commonly referred to as a conductive ring, slip ring, or collector ring) is an electrical component used in XCMG QY16K.70A truck cranes. It is installed at the center of the slewing system to transfer electrical power and control signals between the stationary lower chassis and the rotating upper structure during continuous 360° slewing operations.
1. Installation Location
The electric swivel is mounted at the geometric center of the crane's slewing joint, coaxial with the slewing bearing. It passes through the center of the turntable, with the stationary part fixed to the lower chassis and the rotating part connected to the upper structure. This central location allows it to serve as the electrical interface between the cab/chassis systems and the superstructure controls and lighting.
2. Function
The primary function of the electric swivel is to maintain continuous electrical continuity for power supply and control signals while the upper structure rotates a full 360°. It prevents wiring harnesses from twisting, tangling, or breaking during repeated slewing movements. The device typically consists of stationary carbon or metal-graphite brushes that ride on rotating conductive rings, each ring corresponding to a separate circuit (e.g., main power, control signals, lighting, and sensors). For the QY16K.70A, this ensures reliable operation of the hoist, swing, boom control, and operator display systems regardless of turntable position.
3. Maintenance and Service
Regular inspection of the electric swivel includes checking the brush contact surfaces for wear, cleaning any carbon dust or debris from the ring tracks, and ensuring all terminal connections are tight and corrosion-free. If the brushes are worn beyond the service limit, they should be replaced. The ring surfaces should be periodically cleaned with a soft, lint-free cloth and an appropriate contact cleaner. If the unit shows signs of arcing, intermittent signal loss, or excessive heating, it may indicate brush wear, ring damage, or loose connections. Internal repairs beyond brush replacement typically require specialized service; in many cases, complete assembly replacement is recommended for severe wear or damage. After service, ensure all wires are correctly reconnected to their original circuit positions.
4. Important Notes
Always disconnect the main battery power and ensure the slewing system is locked before removing or installing the electric swivel. Verify that the replacement unit matches the original specification for the QY16K.70A model in terms of circuit count, current rating, and voltage capacity. Use dielectric grease on terminal connections in high-humidity environments to prevent corrosion. After installation, test all crane functions through several full 360° rotations to confirm smooth signal transmission and proper electrical continuity.
