APG Process Epoxy Resin

The FLN36-12D Indoor SF6 Load Switch features an innovative three-position integrated design that combines closing, opening, and earthing functions within a single, sealed SF6 gas chamber. This integration eliminates the need for separate earthing switches and their associated mechanical linkages, significantly reducing the switchgear's physical footprint while enhancing operational reliability .

The three operating positions are clearly defined and mechanically interlocked. In the closed position, the main circuit carries rated current up to 630A. The open position creates a visible isolation gap with high dielectric strength, verified by a power frequency withstand voltage of 48kV across the open contacts. The earthing position securely connects the output terminal to ground through a dedicated earthing switch rated for 20kA/2s short-time withstand current, ensuring safe maintenance access .

The switch achieves its compact footprint through a rotary moving contact design. A single rotating contact arm moves between the three fixed positions within the sealed epoxy resin housing, minimizing the number of moving parts. This elegant mechanical solution reduces potential failure points compared to designs requiring separate mechanisms for each function. The phase-to-phase spacing is optimized for standard 12kV switchgear dimensions, typically 210mm ±0.5mm .

The sealed SF6 environment protects all three functional positions from environmental contamination. The housing is manufactured using APG (Automatic Pressure Gelation) process epoxy resin, ensuring void-free insulation and consistent dielectric performance regardless of external humidity or pollution levels. An integrated pressure gauge allows operators to monitor SF6 gas pressure (0.04-0.05 MPa at 20°C) without opening the sealed chamber .

Therefore, for switchgear manufacturers seeking to reduce cabinet size while maintaining full switching and earthing functionality, the FLN36-12D's three-position design offers a proven, space-efficient solution. Putai also supports customization and the supply of related medium-voltage accessories to meet system integration needs. For detailed dimensional drawings and integration guidance, contact our engineering team.
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