benderIRDH575 SeriesDigital Ground Fault Monitor / Ground Detector Controller for Ground Fault Location System Ungrounded (Floating) AC/DC Systems

Features

• Universal application in 3(N)AC, AC/DC 

and DC ungrounded systems 20…575 

V/340…760 V

• Response range 1 kΩ…10 MΩ

• Info key for the indication of various 

parameters and the system leakage 

capacitance

• Comprehensive self-monitoring function 

including system fault alarm relay

• Internal/external test and reset button

• Two separate alarm relays, operating 

normally energized or normally de-energized

• Backlit LCD display

• RS-485 interface

• Data memory, system disconnection and 

0/4…20mA current output

• Extendable to ground fault

location system for 1080 circuits

• Adjustable test current for ground fault 

location

Description

The IRDH575 monitors for ground faults in ungrounded AC (20 - 760 V, single- and threephase) and DC (20 - 575 V) by measuring the system's insulation resistance. Systems with 

extensive power conversion devices, such as rectifiers and variable frequency drives, are 

supported by the IRDH575. The IRDH575 is able to detect ground faults in ungrounded 

systems before leakage current may even be present.

When combined with EDS4… ground fault location devices and the appropriate current 

transformers, the IRDH575 becomes a controller for a ground fault location system.

Function: Ground fault detection

When the insulation resistance from system to ground falls below the set response value, 

the alarm relays switch and the alarm LEDs activate. Two separately adjustable alarm 

contacts can be set to a prewarning and main warning alarm. The measured value is indicated on the LCD display or on an externally connected meter. If the device is set to nonlatching mode, the alarms will clear when the ground fault clears. If the device is set to 

latching mode, the alarms will not reset until the device is reset manually or the supply 

voltage is lost. An external and internal test/reset can be activated remotely or on the device. A comprehensive INFO menu key displays additional information such as the current leakage capacitance and device settings.

The IRDH575 continuously monitors the equipment ground connection and line connections to ensure proper operation. The device's easy-to-use onboard menu manages all 

settings via the detailed LCD screen.

Function: Ground fault location

When a ground fault is detected, the EDS ground fault location system is activated (this 

feature can be set to require a manual start as well). Each channel of the EDS location device is connected to a particular branch circuit. The IRDH575 begins transmitting a pulsed 

signal. This signal will travel through the channel of the EDS with the ground fault back 

to the IRDH575. If the pulse travels back to the IRDH575, the channel with the ground 

fault will display on both the IRDH575 and the EDS device.

In addition, an optional EDS30... portable ground fault location system can be used to follow the pulse travelling to the source of the ground fault.

Additional functions 

99 timestamped alarm messages may be stored in the non-volatile memory of the 

IRDH575. The device also includes standby contacts when several A-ISOMETER® detectors 

are operating in coupled ungrounded systems.

Two-way data communication is carried out between devices via an RS-485 interface. 

This interface can be connected to a BENDER protocol converter to exchange data across 

other protocols, such as Ethernet, MODBUS, or PROFIBUS.

A 0/4 - 20 mA output can be connected to an external meter or higher-level control system, such as a PLC. 

System design

Each isolated system requires one IRDH575 for ground fault detection and location control. Up to 90 EDS46... devices can be interconnected to the IRDH575. Each EDS device 

can monitor up to 12 separate channels. An optional EDS30.... portable ground fault location system can be used in conjunction with the IRDH575/EDS46... system.

1 - INFO key: Displays pertinent system information

ESC key: Goes back a step inside device's menu

2 - TEST button: Activates self-test

Arrow up key: Scrolls down inside device's menu

3 - RESET button: Resets device

Arrow down key: Scrolls down inside device's menu

4 - MENU key: Activates device's internal menu

Enter key: Confirm change inside device's menu

5 - Alarm LED 1 lights: Insulation fault, warning level reached

6 - Alarm LED 2 lights: Insulation fault, alarm level reached

7 - EDS LED lights: Indicates ground fault location is active

8 - EDS alarm LED lights: Indicates EDS ground fault location device is in alarm

9 - LED lights: Indicates system fault alarm

10 - Real-time measurement of insulation resistance in kΩ

11 - Additional information - "s" displayed when device has begin a 

new measurement

12 - Active when EDS4… is connected and in alarm; indicates 

address of EDS4… in alarm

13 - Active when EDS4… is connected and in alarm; indicates 

channel of EDS4… in alarm

14 - Active when EDS4… is connected and in alarm; indicates 

strength of test signal detected by the channel in alarm (mea

sured in mA or µA)

15 - Active when EDS4… is connected. Displays mode of operation 

for ground fault location system. AUTO indicates location system is activated automatically when IRDH575 goes into alarm. 

System may also be set manually on or off.

16 - Polarity of the test current pulse. Point = valid BMS traffic,

H = A new entry has been made in the history.

17 - Text indicating state of device

18 - Analog output: 0…20 mA or 4…20 mA (selectable)

19 - External test button (N/D contact)

20 - External reset button (N/E contact or wire jumper). When the 

terminals are open, the device will reset automatically.

21 - STANDBY contacts. When the contacts are closed, the device 

is forced into standby mode and will not send out a measurement signal.

22 - RS-485 termination (120 Ω) with micro switch S1 and connection 

BMS bus; S1 = ON = BMS bus terminated, S2 = unassigned

23 - Alarm relay: Alarm 1 (A-ISOMETER®)

24 - Alarm relay: Alarm 2 (A-ISOMETER®)

25 - Alarm relay: System fault and EDS alarm (Adr.:1)

1 - A-ISOMETER® IRDH575

2 - RS-485/BMS protocol

3 - EDS460/EDS461

4 - EDS3090/EDS3091

Example: IRDH575 with EDS460 (main circuits)

EDS460 system with IRDH575, EDS460 and measuring current 

transformers W… in a three-phase AC system

1 - 3AC/3NAC/AC 20…575 V

2 - US

 see ordering information, 6 A fuse recommended.

3 - Current transformers, W series

4 - Loads

5 - A-ISOMETER® IRDH575

6 - Ground fault location device EDS460

Example: IRDH575 with EDS461 (control circuits)

1 - DC 20 V…308 V

2 - US

 see ordering information, 6 A fuse recommended.

3 - Current transformers, W…/8000 series

4 - Load PLC

5 - A-ISOMETER® IRDH575

6 - Ground fault location device EDS461

Design of an EDS461 system

The above example shows an EDS461 device being fed by a PLC 

in a DC system. Using an EDS461 device is recommended for PLC 

inputs due to the sensitivity required.