MRO Magazine

ISOMETER insulation monitoring

July 21, 2014 - With the new insulation monitoring device iso685-D, Bender is focusing on a new innovative series of insulation monitoring devices that are state-of-the-art in relation to reliability, measuring technique, operability and design.


July 21, 2014
By PEM Magazine

For the first time a high-resolution display is used in a monitoring device from Bender for the indication of the measured values as well as for making device settings. This display makes it possible to indicate the changes in the insulation values over time using a graph, the isoGraph. In this way the insulation value trend can be estimated and corresponding measures initiated.

The integrated data loggers save both the measured values and the device error and alarm messages in their entirety for the recommended device service life (up to 10 years) with exact allocation of date and time. Event-based fault analysis is therefore possible in conjunction with additionally acquired system measured data.

The iso685-D easily replaces all installed Three-Light-Systems in ungrounded systems which were installed based on CEC 22.1 / 10-106 because of its capability to monitor AC and DC systems as well as symmetrical and asymmetrical faults.

Due to the internal resistance of 124 kΩ and a maximum measuring voltage of ± 50 V the measuring current is only ± 400 µA. By means of pre-defined measurement profiles the iso685-D can be very easily adjusted to the system to be monitored. Special profiles for inverter applications already include integrated suppression of interfering system fluctuations


Systems with leakage capacitances of up to 1000 µF can be monitored using the iso685-D. Continuous monitoring of the protective earth conductor as well as the improved measuring technique, which ensures the insulation faults and the system leakage capacitance are measured more accurately and more quickly, provide additional safety.

The iso685 provides continuous coupling monitoring as well as a voltage and frequency measurement on the system to be monitored due to the coupling to all active conductors. Systems up to max. DC 1150 V (including any tolerance) can be monitored without additional couplers.

A commissioning wizard also simplifies initial commissioning

Three digital inputs, two digital outputs as well as an analogue output are available as interfaces. The digital inputs and outputs can be programmed as required. The RS-485 interface also makes measured values available on the BMS bus for other display devices and the values can be read. Due to the built-in Ethernet interface, Bender service can support you with configuration, troubleshooting and/or fault analysis.

Furthermore, the usage of plug-type terminals ensures efficient installation.

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