Under-voltage monitoring relay LINETRA ® VME421H series

over-voltagefrequency1 NO/NC

Overview
The LINETRAXX® VME421H is a compact voltage and frequency monitoring relay for AC and DC systems. It monitors undervoltage, overvoltage, frequency and voltage window conditions and measures voltages as r.m.s. values. The device is powered from the monitored system and includes an internal energy backup to maintain function during short interruptions.

Key features

• Undervoltage, overvoltage, frequency and window-discriminator monitoring (selectable functions: <U, >U, <f, >f)
• RMS measurement for AC and DC signals
• Continuous digital measured-value display on multi-functional LC display; measured value at alarm is stored
• Adjustable start-up delay, response delay and delay on release; adjustable switching hysteresis
• Device powered from monitored system; integrated energy backup (no external supply required)
• Two independent alarm relays (one changeover contact each)
• Password protection for settings and Preset function for basic parameter assignment

Additional features / Design

• LED indicators: Power On, Alarm 1, Alarm 2
• Measured-value memory for operating/trip value
• Continuous self-monitoring and internal Test/Reset button
• Selectable N/C or N/O operation and fault memory behaviour
• Sealable transparent cover; two-module enclosure (36 mm)
• Push-wire terminals (two terminals per connection)
• RoHS-compliant

Applications

• Voltage and frequency monitoring of single-phase machines and electrical installations
• Earth-fault monitoring in medium-voltage systems via voltage transformers
• Battery system monitoring
• Automatic switching of equipment at defined voltage thresholds

Variants
VME421H-D-1 | Nominal system voltage: DC/AC 9.6…150 V, 15…46 Hz (response: AC/DC 9.6…150 V) | Art. No.: B73010003 / B93010003
VME421H-D-2 | Nominal system voltage: DC/AC 70…300 V, 15…460 Hz (response: AC/DC 70…300 V) | Art. No.: B73010004 / B93010004

Optional accessories

• Mounting clip for screw mounting (one piece per device): Art. No. B98060008

Downloads (available documentation)
Quickstart (VME421H); Manual (VME421H); Datasheet (VME421H); Series declarations (VMx42x) — CE/UKCA

Technical specifications

• Monitoring functions: undervoltage, overvoltage, frequency, window discriminator
• Measured value type: RMS (AC + DC)
• Display: multi-functional LC display with measured-value memory
• Supply: device supplied from monitored system; integrated internal energy backup
• Outputs: two independent alarm relays (changeover contacts)
• Adjustments: start-up delay, response delay, delay on release, switching hysteresis
• Connections: push-wire terminals (two terminals per connection)
• Mechanical: two-module enclosure (36 mm); sealable transparent cover
• Indicators: Power On, Alarm 1, Alarm 2 LEDs
• Compliance: RoHS