This relay monitors its own working voltage with true RMS measurement. It features 8 selectable rated voltage settings and a voltage measurement accuracy within 1%. The working status is indicated by LED indicators. Designed with a compact size, it can be easily mounted on a 35mm DIN rail.Application: Suitable for equipment protection and control in applications such as tower cranes, elevators, agricultural machinery, and refrigerated trucks. It protects equipment from reverse operation and phase failure in dynamic loads, and supports normal or emergency power supply switching.Function: Monitors line-to-line voltage in a 3-phase 3-wire system. Monitoring terminals: L1, L2, L3 Power supply: L1-L2 Rated working voltage: 220, 230, 240, 380, 400, 415, 440, 460 V (phase-to-phase) Rated power frequency: 45 Hz to 65 Hz Measuring range: 176 V to 552 V Voltage threshold range: 2% to 20% of rated voltage Voltage fixed hysteresis: 2% Voltage measurement error: 1% Power-on delay time: 0.5 s Knob setting accuracy: 10% Reset time: 1 s Temperature fluctuation error: 0.05%/C at 20C Output: 1 x SPDT relay, 10 A resistive, 250 VAC / 24 VDC Minimum switching power: 500 mW Overvoltage protection range: +2% to +20% Undervoltage protection range: -20% to -2% Adjustable response delay time: 0.1 s to 10 s Phase sequence protection: Yes Phase failure protection: Yes Power indicator: Green LED Output relay status indicator: Red LED Mechanical life: 10 million operations Mounting method: 35 mm DIN rail Maximum installation altitude: 2000 m Weight: 78 g (2.7 oz) Dimensions: 95 x 18 x 64 mm Color: White Material: Plastic Package Contents: 1 x Voltage Monitoring Relay 1 x Instruction Manual Note: The package includes only the items listed above. Other accessories are not included. Due to lighting and display differences, the actual product color may vary slightly from the image. Measurement tolerances may vary by 13 cm.