The RCMA470LY‑21 is a high‑performance residual current monitor from Bender, part of the RCMA series. It is designed for earthed systems (TN and TT systems). The device uses advanced fluxgate and differential current transformer technology to reliably detect smooth DC, pulsating DC and AC residual currents (Type B full current sensitivity). Measurement is performed non‑invasively via an external measuring current transformer. In the event of an earth fault, the device provides an early warning without disconnecting the power supply, effectively avoiding nuisance tripping caused by high sensitivity. This model features an LCD display and a Modbus RTU communication interface, making it suitable for modern AC/DC hybrid systems with frequency converters, switch‑mode power supplies, and EV chargers.
Technical Specifications
· Order No.: B94042008
· Response value (main alarm IΔn): AC/DC 30 mA … 3 A (0 … 150 Hz), steplessly adjustable
· Pre‑warning value (IΔn₂): Can be set to 50% or 100% of the main alarm value
· Frequency range: DC … 10 kHz
· Measurement range (extended): 0.1 mA … 10 A (high‑precision detection of tiny leakage currents)
· Supply voltage: DC 9.5 … 84 V
· Power consumption: 3.5 VA
· Alarm outputs: Two independent SPDT potential‑free changeover contacts, AC 250 V / 5 A
· Communication interface: RS‑485 Modbus RTU
· Event log: Built‑in memory, stores up to 100 time‑stamped event records
· Display: LCD screen + LED bar graph (0‑100% indication)
· Protection class: Front panel IP54, overall IP20
· Mounting: 35 mm DIN rail, width 36 mm (2 standard modules)
· Operating temperature: –25 °C … +60 °C
· Storage temperature: –40 °C … +85 °C
· Data sheet: 404001
Key Features
· True Type B full current sensitivity: Monitors smooth DC, pulsating DC and AC residual currents, fully compatible with modern power electronic systems.
· LCD display and LED bar graph: Real‑time display of residual current and device status; bar graph shows measured value as percentage of set value.
· Dual independent alarm values (pre‑warning/main alarm): Two SPDT relay outputs; pre‑warning value can be set to 50% or 100% of the main alarm value.
· Adjustable response delay: 0 … 10 s, prevents nuisance tripping due to transient disturbances.
· Connection monitoring (CT supervision): Continuously monitors external current transformer connection; alarms immediately on wire break.
· Selectable fault memory: Latching mode (manual or power‑cycle reset) or non‑latching mode (auto‑reset after fault clearance).
· Self‑test and reset: Built‑in TEST/RESET button on front panel, also supports external push‑buttons for remote operation.
· RS‑485 Modbus RTU communication: Transmits real‑time measured values and alarm status to SCADA, BMS or cloud platforms.
· Event log: Stores up to 100 time‑stamped events for post‑fault analysis.
· Sealable transparent cover: Prevents unauthorised parameter changes.
Typical Applications
· Residual current monitoring in earthed systems (TN/TT systems)
· Variable frequency drive systems, photovoltaic systems, battery chargers, UPS systems
· Data centres, medical locations (operating theatres, ICUs), laboratory equipment
· EV charging stations, industrial automation production lines
· Off‑line single‑conductor current monitoring (PE conductor, N conductor)
· Refrigeration equipment, alarm systems, safety devices, industrial controls
Translation missing: en.general.search.loading