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.

• 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