Bender ISO685-D Insulation Monitoring Device

Product Overview

The Bender ISO685-D (ISOMETER® iso685-D) is an Insulation Monitoring Device (IMD) designed for continuous monitoring of insulation resistance in ungrounded IT AC, DC, and AC/DC electrical systems. It detects insulation deterioration and ground faults at an early stage without interrupting power operation, improving system safety and availability.

The iso685-D features an integrated high-resolution graphic LCD display and operating buttons, allowing direct parameter setting and fault diagnosis on the device.

Main Specifications

• Manufacturer: Bender
• Model: ISO685-D / ISOMETER® iso685-D
• Product Type:
  • Insulation Monitoring Device (IMD)
  • Ground Fault Monitor
  • Insulation Resistance Monitoring Relay
• System Type: IT systems (ungrounded power systems)
• Applicable Systems: AC, 3(N)AC, DC, AC/DC systems
• Rated System Voltage:
  • AC 0…690 V
  • DC 0…1000 V
• Supply Voltage: AC/DC 24…240 V
• Display: Integrated graphic LCD display
• Mounting: DIN rail / panel installation
• Standard: IEC 61557-8

Technical Specifications

Functions

The ISO685-D provides:

• Continuous insulation resistance monitoring
• Early detection of ground insulation faults
• Real-time insulation value display
• Alarm and fault memory recording
• System voltage monitoring
• Leakage capacitance measurement
• Remote communication and diagnostics

Working principle:

IT Power System → ISO685-D Measurement Circuit → Insulation Resistance Analysis → Alarm Output / Control System

Features & Advantages

• Original Bender ISOMETER® series device
• Monitors insulation without disconnecting power
• Suitable for AC, DC, and mixed AC/DC systems
• Supports systems with converters, inverters, and variable speed drives
• Integrated display simplifies commissioning and troubleshooting
• Supports industrial communication networks
• Helps prevent unexpected equipment downtime

Applications

Used in:

• Industrial automation systems
• Power distribution cabinets
• CNC machines
• Renewable energy systems
• UPS and battery systems
• Medical electrical systems
• Marine and transportation systems
• Inverter and drive systems

Typical applications:

• Ground fault monitoring
• Insulation degradation detection
• Preventive electrical maintenance