Hioki IR4057-50 Insulation Tester
The IR4057-50 is the professional-grade insulation tester for maintenance engineers running predictive maintenance programmes. Auto-calculation of Polarisation Index (PI) and Dielectric Absorption Ratio (DAR) — the time-based tests that reveal insulation condition far more reliably than a single resistance reading — makes it indispensable for rotating machine and transformer maintenance.
Key Features
- 5 test voltages: 50V, 125V, 250V, 500V, 1000V
- Measurement range up to 4000 MΩ
- Automatic PI (Polarisation Index) calculation — 10 min / 1 min ratio
- Automatic DAR (Dielectric Absorption Ratio) calculation — 60 sec / 30 sec ratio
- Displays 1-minute values continuously during testing
- Bluetooth wireless via Z3210 for data transfer to Gennect Cross app
- DC voltage measurement up to 600V
- CAT III 600V, IP40 rated
- 1-drop proof from 1 metre
Understanding PI and DAR Values
PI above 2.0 indicates good insulation for most motors and generators. PI of 1.0–2.0 indicates questionable condition — investigate further. DAR above 1.4 indicates good insulation. These tests are essential for condition-based maintenance of critical rotating equipment.
Applications
Motor insulation condition monitoring, transformer testing, predictive maintenance programmes, pre-commissioning insulation checks and annual electrical safety inspections in industrial plants.
