• Insulation monitoring device for AC IT systems and de-energised loads
  • Automatic activation of the function for de-energised loads
  • According to IEC 61557-8
  • Two separately configurable response values
  • LED bar graph indicator for insulation resistance

The ISOMETER® of the IR470LY2 series is designed to monitor the insulation resistance of unearthed AC and three-phase systems (IT systems) AC/3(N)AC 0…793 V. Two separately adjustable response values/alarm relays allow a distinction to be made between "prewarning" and "alarm". In combination with a coupling device the device series can be used for higher voltages.

The systems to be monitored should not contain DC components. Due to the measuring principle, insulation faults behind directly connected rectifiers are indicated with increased response sensitivity. The set response values apply to the pure AC system only.

The product has been discontinued

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  • Insulation monitoring for AC, 3(N)AC systems 0…793 V (IT systems)
  • Nominal voltage extendable via coupling device
  • Two separately adjustable response values 10…100 kΩ/35…500 kΩ
  • Connection monitoring system/earth
  • LEDs: Power ON LED, LED to signal AC insulation faults
  • LED bar graph indicator for the indication of the insulation resistance
  • Connection for external kΩ indication
  • Combined test and reset button
  • Two separate alarm relays with one potential-free changeover contact each
  • N/O or N/C operation, selectable
  • Fault memory behaviour, selectable
  • AC, 3(N)AC main circuits (without directly connected rectifiers), such as motors, pumps, rolling mills without variable-speed drives, air cooling and air conditioning systems, lighting systems, heating systems, mobile generators, building services, domestic electrical installation practice, etc.


Optional accessories for ISOMETER® IR470LY2-4061

External kΩ measuring instruments
TypeArt. No.

Coupling devices
TypeNominal system voltage UnArt. No.
AGH204S-4AC 0…1650 VB914013
AGH520SAC 0…7200 VB913033

Variants of ISOMETER® IR470LY2-4061

TypeSupply voltage USArt. No.
IR470LY2-4061AC 230 VB91048052
Other supply voltages on request.

Downloads for ISOMETER® IR470LY2-4061



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