IRDH575B1W-435 Insulation monitoring device

When the insulation resistance between the system conductors and earth falls below the set response value, the alarm relays switch and the alarm LEDs light up. Two separately
adjustable alarm relays allow to distinguish between prewarning and alarm. The measured value is indicated on the LC display or an externally connectable measuring instrument.
In this way any changes, for example when circuits are connected to the system, can be recognised easily. The fault message can be stored. The fault memory can be reset by
pressing the reset button. By pressing the test button, the function of the device as well as the connections to system and earth can be tested. Pressing the Info button provides
additional information, such as the existing system leakage capacitance or device settings.
The function of the device and the system and earth connections are continuously monitored. When a fault occurs, the system fault relay switches and the alarm LED “system fault”
lights up. The parameterisation of the device can be carried out via the LC display or the function buttons integrated in the front plate.

IRDH575B1W-435

Product description
The ISOMETER® of the IRDH275 series is designed to monitor the insulation resistance of unearthed main circuits (IT systems) AC, AC/DC 0…793 V resp. DC 0…650 V. The AMPPlus
measurement method meets the particular requirements of modern power supplies which often include rectifiers, converters, thyristor-controlled DC drives and directly connected
DC components. In these systems often high leakage capacitances against earth occur due to interference suppression measures. The IRDH275 automatically adapts itself to the
existing system conditions.
In combination with a coupling device, the devices can also be used for higher voltages. An external supply voltage allows de-energised systems to be monitored too. For door
mounting into distribution panels, refer to type IRDH375(B).

Device version IRDH275B
Device version IRDH275B includes the following additional functions:
• History memory with real-time clock to store all alarm messages with date and time stamp
• Electrically isolated RS-485 interface (BMS protocol) for communication with other Bender devices
• Isometer disconnecting relays for the operation of several ISOMETER®s in coupled IT systems
• Current output 0(4 )…20 mA (electrically isolated)