The RCMA423-D9-1 is a Type B AC/DC sensitive residual current monitor designed for earthed systems (TN and TT systems) where smooth DC fault currents or residual currents may occur. It is suitable for loads with six‑pulse rectifiers or single‑phase rectifiers with smoothing, such as frequency converters, battery chargers, and construction site equipment with variable‑frequency drives.
The device performs non‑invasive measurements via external measuring current transformers, largely unaffected by load current and rated system voltage. When an earth fault is detected, the device triggers an alarm without disconnecting the power supply, providing advanced warning of developing ground faults. It complies with IEC 62020 and IEC 60755 Type B standards.
Technical Specifications
· Order No.: B74043023 (push‑wire terminals); B94043023 (screw‑type terminals)
· Supply voltage (Uₛ): DC 9.6…94 V; AC 16…72 V, 42…460 Hz
· Frequency range: 0…2000 Hz
· Response value range (main alarm IΔn₂): 30 mA…3 A (adjustable), factory preset 30 mA
· Pre‑warning value (IΔn₁): 50…100 % of IΔn₂, min. 15 mA, factory preset 15 mA
· Hysteresis: 10…25 %, factory preset 15 %
· Response time: at IΔ = 1 × IΔn₂ ≤ 180 ms; at IΔ = 5 × IΔn₂ ≤ 30 ms
· Measuring principle: True RMS measurement (AC+DC)
· Measuring range: 0…6 A
· Alarm outputs: Two independent changeover contacts (SPDT), AC 250 V / 5 A
· Adjustable time delays: Start‑up delay 0…10 s, response delay 0…10 s, delay on release 0…99 s
· Display: Multi‑function LC display showing real‑time measured values
· LED indicators: Power On (green), Alarm 1 (yellow), Alarm 2 (yellow)
· Operating temperature: –25 °C … +55 °C
· Protection class: Internal components IP30, terminals IP20
· Mounting: 35 mm DIN rail (2 modules, width 36 mm)
· Weight: ≤ 150 g
· Standards compliance: IEC 62020, IEC 60755 (Type B)
Key Features
· Type B full current sensitivity: Compliant with IEC 60755 Type B; detects smooth DC, pulsating DC and AC residual currents, fully compatible with frequency converters, battery chargers, construction site equipment with variable‑frequency drives and other modern power electronic systems
· Two independent alarm stages: Pre‑warning (IΔn₁) and main alarm (IΔn₂); pre‑warning value adjustable from 50…100 % of IΔn₂ for staged alarming
· External measuring current transformer: Non‑invasive measurement via W20AB, W35AB, W60AB, W120AB, W210AB series current transformers; largely unaffected by load current and system voltage
· True RMS measurement (AC+DC): Ensures measurement accuracy even in harmonic‑rich environments
· Adjustable time delays: Start‑up delay, response delay and delay on release to prevent nuisance tripping
· Selectable fault memory: Latching (manual reset) or non‑latching (auto reset) mode
· Self‑test and reset: Built‑in TEST/RESET button (short press < 1.5 s = reset, long press > 1.5 s = test); supports external push‑buttons for remote operation
· Transformer connection monitoring: ON/AL1/AL2 LEDs flash and K1/K2 relays switch immediately on wire break or system fault
· Password protection: Prevents unauthorised parameter changes
· Sealable transparent cover: Prevents unauthorised parameter changes
Typical Applications
· Residual current monitoring in earthed systems (TN/TT systems)
· Loads with six‑pulse rectifiers or single‑phase rectifiers with smoothing: Frequency converters, battery chargers, construction site equipment with variable‑frequency drives
· Variable‑speed drives, UPS systems, printing machines, battery systems, laboratory equipment, woodworking machines, MF welding systems
· Single‑conductor current monitoring: Normally de‑energised conductors (PE conductors, N-PE connections)
· Data centres: Monitoring earth leakage in server racks and critical IT equipment
· Medical locations: Leakage current monitoring in operating theatres, ICUs and other critical areas
· Residual current monitoring in fire‑hazard locations
Translation missing: en.general.search.loading