Insulation Resistance Testers Measure Tiny Leakage Current Flowing Through Insulators
The Insulation Resistance Tester (commonly known as "Megohmmeter" or "Megger") is an essential testing tool in power system maintenance, electrical equipment installation, and repair. It is primarily used to measure the insulation resistance of high-voltage electrical equipment such as transformers, cables, motors, and switches, to determine whether the equipment's insulation performance is satisfactory.
Based on Yangzhou city and the latest technological developments of 2026, here is a summary of the equipment's core principles, selection parameters, and local procurement recommendations.
⚡ Core Principles and Functions
The working principle of Insulation Resistance Testers is based on Ohm's Law (R=U/I).
Operating Method: Inside the instrument, a DC-DC converter circuit converts the battery's low-voltage DC power into high-voltage DC power (such as 500V, 2500V, 5000V, etc.), which is then applied to the insulator under test.
Measurement Process: The instrument measures the tiny leakage current flowing through the insulator and automatically calculates the resistance value. A higher resistance value indicates better insulation performance; conversely, a lower value suggests insulation dampness or aging.
Intelligent Features: Mainstream equipment in 2026 already features highly intelligent functions, capable of automatically calculating the Dielectric Absorption Ratio (DAR) and Polarization Index (PI), with an automatic discharge function to ensure equipment safety after testing.
