Rockwill Indoor g3 Load Break Switch: Technical Advantages of Three-Set Rotating Fixed and Moving Contacts

For the Rockwill Indoor g3 eco-friendly gas load break switch (LBS), the adoption of "three sets of rotating fixed and moving contacts" – a typical rotary three-position mechanism – represents a core technology in both gas chamber design and mechanical structure. This design not only inherits the mechanical advantages of conventional SF6 ring main units but also achieves deep compatibility with the electrical characteristics of g3 (Green Gas for Grid) eco-friendly gas.

The following is a breakdown of the core technical advantages of this design:

1. Inherent Mechanical Interlocking and Ultimate Safety (Integrated Three-Position Design)

The three sets of rotating moving contacts are mounted on a single insulated main shaft, enabling switching among three operating positions – "Closed," "Open/Isolated," and "Earthed" – through angular rotation.

• Physical Anti-misoperation: The moving contacts can only occupy one of the three positions at any given time, with the closed and earthed positions spatially separated by a wide angle. This configuration provides a natural mechanical interlock that fundamentally eliminates the risk of dangerous misoperations such as closing the earthing switch onto a live circuit.

• Visual Positivity and Determinacy: The mechanical indicator on the main shaft directly and accurately reflects the actual position of the internal three-phase contacts. The position is unique and unambiguous.

Rockwill RLS Series Eco-friendly Indoor g3 Load Break Switch

2. Optimized Electric Field Distribution for g3 Eco-Friendly Gas Compatibility

g3 gas has an extremely low Global Warming Potential (GWP) and serves as an environmentally friendly alternative to SF6. However, its molecular characteristics make it more sensitive to electric field uniformity compared to SF6.

• Partial Discharge (PD) Suppression: The rotating fixed and moving contacts typically feature rounded or spherical-conical surface profiles, which avoid the sharp edges and guide-rail corners commonly found in linear push-pull contact designs. This streamlined geometry maximizes electric field uniformity.

• Enhanced Insulation Margin: Under the same gas pressure, the optimized contact geometry effectively mitigates corona discharge, compensating for the slightly lower insulation strength of g3 gas compared to pure SF6 under certain non-uniform electric fields, thereby ensuring long-term, PD-free operation.

3. Maximized Space Utilization (Compact Design)

Compactness is a key design criterion for Rockwill's indoor distribution equipment.

• Optimized Motion Path: The operating space required for rotary motion (a sector-shaped sweep area) is significantly smaller than the stroke space required for linear motion.

• Minimized Phase-to-Phase Distance: With three-phase contacts driven by a single shaft, the open gap and earthing clearance are secured by different angular arcs. This substantially reduces the overall footprint of the load switch, making it ideal for space-constrained, compact eco-friendly ring main units (RMUs).

Rockwill RLS Series 36kV SF6-free Indoor g3 Load Break Switch

4. Efficient Interruption and Arc-Quenching Coordination

During interruption of rated load current, the rotating contact structure exhibits superior dynamic characteristics:

• Rapid Opening Speed: The rotating main shaft, coupled with a purely spring-operated mechanism, provides direct torque transmission, imparting a high initial angular velocity to the moving contacts.

• Arc Elongation and Cooling: The rapid rotational separation of fixed and moving contacts quickly elongates the arc. Simultaneously, the rotational motion generates localized gas turbulence around the g3 gas, accelerating arc cooling and extinction, thereby enhancing the switch's arc-withstanding capability and interruption performance.

5. Simplified Transmission Chain with Superior Mechanical Life and Reliability

• Low Failure Rate: Linear motion mechanisms often require conversion of rotational motion from the main shaft into linear push-pull motion via cams or linkages, involving more components and a higher risk of mechanical jamming. The three sets of rotating contacts are directly driven by the insulated main shaft, resulting in the shortest possible transmission chain and an exceptionally simple structure.

• Maintenance-Free Characteristics: Direct and symmetrical force transmission minimizes bearing wear on the main shaft, significantly extending mechanical life – typically achieving several thousand maintenance-free operations – thereby meeting the "full-life-cycle maintenance-free" requirements of modern distribution networks.

Conclusion

The Rockwill Indoor g3 Load Break Switch, featuring three sets of rotating fixed and moving contacts, represents a seamless integration of mechanical reliability (three-position direct drive) and eco-friendly dielectric performance (g3 electric field optimization). It not only achieves cabinet miniaturization and inherent anti-misoperation features but also ensures reliable insulation strength and high-current interruption capability under the new eco-friendly gas atmosphere, thanks to its optimized contact profiles and high-speed rotary arc-quenching characteristics.
Edited From:Garca