Safety instructions
15
IRDH575_D00089_05_M_XXEN/01.2020
When using ISOMETER®s in IT systems, make sure that only
one active ISOMETER® is connected in each interconnected
system. If IT systems are interconnected via coupling
switches, make sure that ISOMETER®s not currently used are
disconnected from the IT system and deactivated. IT systems
coupled via diodes or capacitances may also influence the
insulation monitoring process so that a central control of the
different ISOMETER®s is required.
Prevent measurement errors!
When a monitored IT system contains galvanically coupled
DC circuits, an insulation fault can only be detected correctly
if the rectifier valves (e.g. rectifier diode, thyristors, IGBTs,
frequency inverters, …) carry a minimum current of > 10 mA.
Unspecified frequency range
When connecting to an IT system with frequency
components below the specified frequency range, the
response times and response values may differ from the
indicated technical data. However, depending on the
application and the selected measurement method,
continuous insulation monitoring is also possible in this
frequency range.
There is no influence on the insulation monitoring for IT
systems with frequency components above the specified
frequency range, e.g. within the range of typical switching
frequencies of frequency inverters (2…20 kHz).