Product Introduction

Model Interpretation

• MIRU: Measuring Insulation Resistance Unit

• 01: Standard hardware configuration, revision G

• 3AXD50000033270: ABB’s formal order part number

Technical Parameters

• Supply voltage: 24 V DC

• Measurement range: Typically 10 kΩ – 10 MΩ (application-dependent)

• Measurement accuracy: ±5% of reading

• Operating temperature: −25 °C to +70 °C

• Storage temperature: −40 °C to +70 °C

• Protection class: IP20

• Mounting: 35 mm DIN rail or panel mount

• Weight: 1.23 kg

• Compliance: CE, RoHS, UL 61010-1

Interface and Connection

• Measurement terminals: Screw terminals for connecting to the insulation test object (motor, cable, winding)

• Power terminals: 24 V DC input (±)

• Status output: Relay contact for alarm (resistance below threshold)

• Indicators: Multi‑LED for power, measurement active, and fault/alarm

• Internal circuit: Precision resistance bridge, surge protection, and fault diagnostics

Core Functions

• Continuous insulation resistance monitoring: Tracks trends over time for predictive maintenance

• High‑accuracy measurement: Stable readings under industrial noise conditions

• Adjustable alarm threshold: User‑configurable resistance limit for early warning

• Fault detection: Identifies short circuits, open circuits, and connection faults

• Isolation protection: Galvanic isolation between measurement circuit and system ground

• Compact integration: Designed for installation in control cabinets with drives and PLCs

Application Scenarios

• Medium‑voltage AC drive systems (ACS800, ACS880, ACQ810)

• Motor insulation monitoring in mining, metals, pulp & paper, water treatment

• Power cable and transformer insulation health checks

• Critical equipment preventive maintenance and condition monitoring

• Industrial automation panels and motor control centers (MCC)

Operation and Maintenance Instructions

• Install in a dry, well‑ventilated cabinet; avoid dust, moisture, and corrosive gases

• Use 1.5–2.5 mm² copper wires for measurement and power connections

• Set the alarm threshold according to equipment insulation requirements (typically 1–5 MΩ)

• After power‑on, verify LED status: power OK, measurement active

• Inspect terminals quarterly for looseness, corrosion, or damage

• Keep unit surface clean; avoid covering ventilation slots

• Before replacement, disconnect all power and take ESD precautions

• No routine calibration required; replace only if measurement error persists