BENDER IRDH575 A‑ISOMETER ® Insulation monitoring device

BENDER IRDH575 A‑ISOMETER ®  Insulation monitoring device

BENDER IRDH575 series digital insulation fault monitoring controller product manual. IRDH575 is an insulation monitoring host for IT ungrounded (floating) AC/DC systems. In addition to basic insulation resistance measurement and alarm, it integrates the main control capability of EDS grounding fault location system and can be externally connected to EDS46 series branch positioning units to achieve loop level grounding fault detection; Panel embedded installation, suitable for IT isolated power grids with rectifier and frequency converter loads. Compliant with IEC 61557-8 (insulation monitoring) and IEC 61557-9 (ground fault location) standards.

Core positioning and main features of the product

Applicable to the tested system

IRDH575‑B1：AC 20‑575 V；DC 20‑575 V

IRDH575‑B2：AC 340‑760 V；DC 340‑575 V

Supports single-phase, three-phase 3 (N) AC, pure DC, and a large number of rectifier/variable frequency loads in an AC/DC hybrid IT floating ground system.

Measurement range: Insulation resistance 1   k Ω~10   M Ω, two-level independent alarm thresholds ALARM1 and ALARM2;

Two core functions

① Insulation fault monitoring: Real time measurement system for ground insulation resistance, two-level alarm, supporting latch/non latch mode;

② EDS grounding fault location main control: The host outputs test pulse signals, combined with EDS46 series branch units and dedicated current transformers, to locate the specific branch circuit where the grounding fault occurs; Can be set to automatically trigger or manually start positioning;

Human computer interface: backlit LCD (4 lines x 16 characters), INFO, TEST, RESET, MENU operation buttons; Multiple status LEDs;

Record storage: Non volatile memory can store up to 99 timestamp alarm history records;

Output and Interface

3-channel SPDT conversion relay: Alarm 1 pre alarm, Alarm 2 main alarm, system fault/EDS positioning alarm; Relays can be set with power on/off excitation (NO/NC logic);

Analog output: 0/4-20 mA, can be connected to PLC and external display meter; Maximum load of 500 Ω;

RS-485 (BMS protocol), maximum bus length of 1200mm; onboard 120 Ω terminal resistor dip code; Can be converted to Modbus TCP/Profibus/Ethernet using an external protocol converter;

External TEST and RESET terminals; STANDBY standby terminal (contact closure forces the device to stop measuring output).

Self inspection and monitoring: continuous monitoring of PE grounding, system measurement of wiring integrity; Comprehensive self diagnosis of the whole machine; Support local button self-test and remote external self-test.

Expansion capability of EDS fault location system

A single IRDH575 can connect up to 90 EDS46xx positioning units; Each EDS46 can monitor up to 12 branch circuits; Total maximum monitoring of 1080 circuits;

The positioning test pulse current can be adjusted in multiple levels: 1/2.5/10/25/50 mA; the pulse cycle is sent for 2 seconds and paused for 4 seconds;

Can be paired with a portable handheld positioning device EDS30xx to trace the fault point along the pulse signal.

System rule: An independent IT floating ground system is configured with only one IRDH575 as the monitoring and positioning master.

Panel buttons, LED and LCD display information

Panel buttons

INFO/ESC: INFO to view system leakage capacitance and equipment parameters; ESC in the menu returns to the previous level;

TEST: Start the whole machine self-test; Up/down arrow menu for flipping pages;

RESET: Clear the alarm latch; Adjust parameters with up and down arrows;

MENU/Enter: Enter the menu and confirm parameter modifications.

LED indicator light

Alarm 1: Reached the warning threshold;

Alarm 2: Reached the main alarm threshold;

EDS: The grounding positioning function is running;

EDS-ALARM: EDS branch unit reports a fault;

SYSTEM FAULT: Device/wiring system malfunction.

LCD screen displays content

Current insulation resistance R (k Ω/M Ω); S represents being measured;

EDS fault location information: fault EDS unit address ADR, fault channel number, detected test signal current;

EDS working mode: AUTO (automatic positioning after insulation alarm)/MANUAL manual;

Historical record marking, pulse polarity indication.

Definition of Backboard Terminals

A1 (+)/A2 (-): Auxiliary power supply Us, it is recommended to install a 6A fuse at the front end;

L1/L2/L3: Measurement inputs for three-phase/DC positive and negative poles of the tested IT system;

KE: The protective grounding PE must be reliably grounded;

M+/M ---: 0/4-20 mA analog output;

T1/T2: External TEST button;

R1/R2: External RESET terminal; Terminal open circuit automatic reset, short circuit enable fault latch;

F1/F2: STANDBY standby contact, close the device to enter standby mode and stop outputting measurement pulses;

A/B: RS-485-BMS bus, S1 dialing opens the built-in 120 Ω terminal;

relay output

11-12-14: Alarm 1 pre alarm relay;

21-22-24: Alarm 2 main alarm relay;

31-32-34: System malfunction+EDS alarm relay.

Key technical parameters

Tested system

Model B1 version B2 version

AC system 20-575   V 340-760   V

DC system 20-575   V 340-575   V

Frequency 50-460 Hz 50-460 Hz

Insulation alarm setting: 1   k Ω~10   M Ω; hysteresis of 25%+2   k Ω;

The system allows a maximum ground leakage capacitance Ce of up to 500 μ F; The larger the leakage capacitance, the longer the measurement response time. The manual includes a response time characteristic curve chart;

Measure voltage Um ≤ 40   V; short-circuit measurement current ≤ 220   μ A.

Electrical output

Three sets of SPDT relays; AC250V / DC300V； Mechanical lifespan of 12000 cycles;

Analog output 0/4-20 mA, load ≤ 500 Ω;

RS‑485‑BMS， Shielded cable, maximum bus length of 1200 meters;

The overall power consumption of the machine is ≤ 14   VA.

Environment and Machinery

Working temperature -10~+55 ℃; Storage -40~+70 ℃; Climate level 3K5;

Anti impact and vibration meet the requirements of IEC 60068 series;

Cabinet panel opening: 138  × 90   mm; overall appearance: 144  × 96  × 133   mm; weight ≤ 900   g;

Protection: IP30 inside the device; Terminal IP20; Cabinet door installation status IP40; UL94-V-1 flame retardant;

Certification: RoHS; IEC 61557-8, IEC 61557-9.

Composition of EDS grounding fault location system

IRDH575: Host, generates positioning test pulses, bus manages all EDS slave stations;

EDS460: Main power circuit positioning unit (three-phase high-power circuit), equipped with W series current transformers;

EDS461: Control/small signal DC circuit positioning unit, suitable for PLC control circuits;

W-xxx series specialized transformers: threaded on various branch cables to pick up positioning pulse signals;

EDS3090/3091 portable handheld locator: handheld on site, further accurately locate the physical location of the fault along the pulse;

Communication link: The RS-485 BMS bus connects IRDH575 with all EDS46 units.

Work logic: IRDH575 detects a system ground insulation reduction alarm → (AUTO mode) automatically outputs a positioning pulse signal; The pulse passes through the branch of the grounding fault and is picked up by the current transformer of the circuit. The EDS46 unit identifies the fault channel and sends the address, channel number, and signal strength back to the IRDH575 host. The screen directly displays which circuit is grounded.

Important usage precautions

Before the voltage/insulation test, disconnect all wiring between IRDH575 and the IT system to avoid damaging the equipment;

Only one IRDH575 is allowed to be used for measurement within the same IT isolated power grid; STANDBY terminal can put multiple devices on standby, with only one activated;

The KE protective grounding terminal must be reliably connected to the PE and cannot be removed with electricity;

External RESET terminal: Short circuit enables fault latch, open circuit fault automatically resets;

The EDS positioning function will inject test pulses into the system during operation, and the positioning will only start after a ground fault occurs, without outputting positioning pulses normally;

The system's ground leakage capacitance Ce will directly affect the measurement response time, and engineering selection requires confirmation of the on-site system leakage capacitance;

The terminal resistor must be enabled at the end of the RS-485 bus to reduce communication interference.

Typical application scenarios

Ship and rail transit IT isolation power supply system;

Medical isolation power supply;

Industrial frequency converter, inverter DC intermediate circuit IT system;

Photovoltaic and energy storage floating DC systems;

It is necessary to locate the specific branch circuit of the ungrounded AC/DC power grid, which not only alarms for insulation faults, but also directly reports the fault circuit number.