Siemens Monitoring Relay, 3 Phase, DPDT, DIN Rail, 120/690 V ac

This monitoring relay is a Compact DIN-rail device for three-phase line surveillance, providing automatic correction of rotation direction and detection of phase failure, sequence and asymmetry in industrial control systems. It monitors frequency Plus three-phase overvoltage and undervoltage windows and can operate with or without a NEUTRAL conductor, making it suitable for motor protection and network supervision across a wide AC voltage range.

• Measures three-phase voltages 90–760 V to protect equipment from supply faults
• Detects overvoltage and undervoltage across three phases for system stability
• Auto-corrects phase sequence to maintain correct motor rotation direction
• Adjustable response and OFF-delay 0.1–30 s to prevent nuisance tripping
• Two changeover contacts provide switching at up to 3A for control circuits
• Galvanic isolation between inputs and outputs to reduce interference risk

• Suitable for motor protection in conveyor and pump control panels
• Ideal for monitoring incoming supply to distribution boards
• Used for frequency-sensitive equipment protection in production lines
• Can be used for phase-sequence supervision in three-phase inverter systems

It accepts an AC control supply across a broad band from 120 to 690 V at both 50Hz and 60Hz with defined operating range factors.

The device provides a minimum buffering time of 20ms to ride through short power disturbances before signalling a fault.

Screw terminals accept solid or stranded conductors from 0.5 to 4 mm² with a stripped length of 10 mm and a recommended tightening torque of 0.6–0.8 N·m.

Typical mechanical life is around 10,000,000 cycles and electrical endurance at AC-15/230 V is about 100,000 operations.

It is rated for operation from −25°C to +60°C, with a maximum installation altitude of 2000m and relative humidity up to 70%.