BENDER VMD420-D-2 Voltage Monitoring Relay

Description

BENDER VMD420-D-2 Voltage Monitoring Relay

Product Dimensions：

The Bender LINETRAXX® VMD420-D-2 is a multi-functional voltage and frequency monitoring relay designed for 3(N)AC systems. It provides comprehensive protection by monitoring overvoltage, undervoltage, and frequency deviations, as well as phase-related faults.

Product Detailed Description

The VMD420-D-2 is a digital monitoring device that measures voltages as true R.M.S. values, ensuring accuracy even in harmonic-rich environments. It features a built-in LC display for real-time monitoring and two independent alarm relays that can be assigned to different fault conditions. The “-D-2” variant is specifically distinguished by its wide-range auxiliary supply voltage.

Technical Parameters

Product Advantages

• Comprehensive Monitoring: A single unit monitors overvoltage, undervoltage, overfrequency, underfrequency, asymmetry, phase failure, and phase sequence.
• True R.M.S. Measurement: Accurate performance even in modern industrial networks with significant power electronic interference (VFDs, UPS).
• Preset Function: Automatically assigns basic parameters upon first connection to a 400V/50Hz system, simplifying commissioning.
• Fault Memory: Includes a latching function that stores the cause of the trip, allowing technicians to diagnose intermittent faults after the system has stabilized.
• Security: Password protection prevents unauthorized tampering with safety setpoints.

Important Considerations (Precautions)

• External Supply: Unlike some self-powered relays, the VMD420-D-2 requires a separate auxiliary supply voltage (U_s) to operate.
• Isolation Testing: Always disconnect the device or remove the measuring inputs before performing high-voltage insulation (Megger) tests to prevent internal damage.
• Fusing: It is highly recommended to install a 6 A fuse on the supply lines (A_1, A_2) to protect the device from line faults.
• Wiring: Ensure correct phase orientation if phase sequence monitoring is enabled; otherwise, the device will trigger a “Phase Sequence” alarm immediately upon startup.

Product Applications

• Machine Safety: Protection of voltage-sensitive motors and industrial machinery against phase loss and overvoltage.
• Emergency Power: Monitoring stand-by and emergency generators to ensure voltage and frequency remain within limits before switching loads.
• Renewable Energy: Voltage and frequency monitoring for grid-tie inverters in solar and wind installations.
• Portable Loads: Monitoring the power quality of mobile equipment and temporary power distribution units.

Shipping Port: Xiamen, China

Payment: Bank of Chicago, Bank of Singapore

Express cooperation: fedex, DHL, UPS and your express account

Service: Professional Sales provides 24 hours /7 days online service

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