• Insulation monitoring device for AC IT systems
  • Application main circuits
  • 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. The device series is particularly suitable for systems requiring a high insulation level. The device can also be used for monitoring de-energized loads. 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

Do you already know our new product generation:

  • Features
  • Applications
  • Accessories
  • Ordering information
  • Downloads
  • Insulation monitoring for unearthed AC, 3(N)AC systems 0…793 V
  • Off-line monitoring for TN, TT and IT systems 0…793 V
  • Nominal voltage extendable via coupling device
  • Operating mode selectable: Insulation monitoring/off-line monitoring
  • Two separately adjustable response values 100 kΩ…1 MΩ/500 kΩ…5 MΩ
  • Connection monitoring system/earth
  • Power ON LED, Alarm LED for signalling AC, L+, L- 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
  • 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.
  • De-energised loads, such as fire extinguisher pumps, slide-valve drives (gas, water, oil etc.), flue gas valves, cranes


Optional accessories for ISOMETER® IR470LY2-60

External kΩ measuring instruments
TypeArt. No.

Coupling devices
TypeNominal system voltage UnArt. No.
AGH520SAC 0…7200 VB913033

Variants of ISOMETER® IR470LY2-60

TypeSupply voltage USArt. No.
IR470LY2-60AC 230 VB91048010
IR470LY2-6013AC 90…132 V*B91048013
IR470LY2-6015AC 400 VB91048009
IR470LY2-6021DC 9,6…84 V*B91048014
Other supply voltages on request
* Absolute values

Downloads for ISOMETER® IR470LY2-60



Category Product Language Date Size Download