K-Electric Undervoltage Monitoring Relay 103030, 2 Changeover Contacts, 400V AC, DIN Rail, 1 TE

Undervoltage monitoring relay for single-phase AC networks up to 400 V AC. This device reliably protects motors, compressors, and other sensitive equipment from damage caused by voltage drops. It monitors the supply voltage and switches its two changeover contacts when the voltage falls below the adjustable threshold. The response delay can be set from 0.1 to 10 seconds to prevent nuisance tripping during brief voltage fluctuations. With a compact 1 TE (18 mm) DIN rail housing, it fits into any standard distribution board.

Advantages

Prevents equipment failure and downtime due to undervoltage. Adjustable threshold and delay allow adaptation to specific application requirements. Clear LED indication shows operating status and relay state. Screw terminals ensure secure and maintenance-free wiring. The fixed 5% hysteresis prevents relay chatter near the threshold.

Suitable for

• Protection of three-phase motors against phase failure and undervoltage
• Monitoring of single-phase supplies for control circuits
• Undervoltage protection in industrial automation systems
• Alarm and shutdown functions in building services

Key specifications

• Nominal voltage: 400 V AC, 50/60 Hz
• Measuring range: 280–400 V AC (0.7–1.0 × Un)
• Adjustable threshold via potentiometer
• Adjustable time delay: 0.1–10 s
• Output: 2 changeover contacts (SPDT), 5 A / 250 V AC
• Mounting: DIN rail EN 60715, width 1 TE (18 mm)
• Indicators: green LED (operating), red LED (relay status)
• Protection: IP40 housing, IP20 terminals
• Operating temperature: -20 °C to +55 °C
• Power consumption: approx. 2 VA

Recommendations

For reliable undervoltage monitoring in industrial and building installations. Combine with a contactor to automatically disconnect loads when voltage drops below the set threshold. Ensure proper phase-to-phase or phase-to-neutral connection according to the application.