Insulation Resistance Tester, Commonly Known as Megohmmeter or Megger
The Insulation Resistance Tester, commonly known as a megohmmeter, megger (named after the old hand-crank generator), or high-resistance meter, is the most fundamental and commonly used testing instrument in power systems and electrical engineering. It is used to measure the insulation resistance of electrical equipment, circuits, or materials. In the complete testing system consisting of the “DC Resistance Tester,” “Dielectric Loss Tester,” and “Test Transformer” you previously inquired about, insulation resistance testing is typically the first step and serves as the “threshold” for determining whether equipment qualifies for subsequent high-voltage testing (such as withstand voltage testing). 1. Core Function & Principle: A stable DC high voltage is applied between two conductive parts, and the weak leakage current flowing through the insulator is measured. The insulation resistance value is then calculated using Ohm’s Law.
2. Insulation resistance testing is the primary step in preventive testing of power equipment, effectively detecting issues such as insulation moisture, aging, and localized defects, ensuring safe and reliable equipment operation.
