Three Phase Adjustable Over and Under Voltage Protector A 3phase automatic recovery protective device and transfer switch designed for continuous operation in 380V systems. The unit monitors phase voltages, switches to a backup source during voltage loss or outofrange conditions, and automatically reverts to the main supply when stable voltage returns. Rated for 63A operation with adjustable overvoltage and undervoltage thresholds, the device delivers reliable power transition control for distribution panels. Key benefits Continuous operation: Automatically switches to backup power during outages and reverts to the main supply when normal voltage is restored, minimizing downtime for connected loads. Adjustable protection: Userselectable overvoltage and undervoltage setpoints let you tailor protection to the specific requirements of your electrical system and equipment. Robust conductivity and long service life: conductivity contacts and durable construction reduce contact resistance and wear for consistent switching performance. Flameretardant and heatresistant components: Insulating materials and structural parts are selected for flame retardance and temperature resistance to maintain insulation performance over time. Easy integration: Compact design fits standard distribution boxes and simplifies retrofits or installations in commercial and municipal systems. Key features and specifications Function: Overvoltage and undervoltage protection with automatic recovery and reset Phase: Threephase monitoring and switching Rated voltage: 380V Rated current: 63A Operation: Automatic transfer to backup source on fault and automatic to main when voltages stabilize Adjustability: Configurable thresholds for overvoltage and undervoltage trip points Construction: conductivity switching contacts and flameretardant, temperature resistant insulating materials Installation: DINrail or distribution box mounting compatible, suitable for professional electrical panels Applications and use scenarios Urban street lighting: Maintain illumination by switching to secondary power during grid disturbances, then automatically restoring to the primary grid when conditions normalize. Shopping centers and malls: Protect lighting, signage, and noncritical building systems from voltage excursions while enabling automatic recovery to avoid manual intervention. Airport and transport infrastructure: Support auxiliary power continuity for nonlifecritical systems where uninterrupted operation and quick recovery reduce operational impact. Installation and operation notes Install the device within a distribution box or panel with access for adjustment of voltage thresholds. Ensure wiring and protective devices upstream and downstream comply with local electrical codes and coordinate protection settings with system requirements. Periodic inspection of connections and contact condition is recommended to maintain longterm reliability. This device is intended for threephase 380V circuits requiring automatic over and under voltage protection with transfer switch functionality at a 63A rating. It is designed for straightforward panel integration and configurable protection to match sitespecific voltage tolerances.