megger

A Megger, also known as an insulation tester, is a specialized electrical instrument used to measure the insulation resistance of electrical systems and components. It is widely used in various industries, including electrical maintenance, manufacturing, and installation, to ensure the safety and reliability of electrical equipment.

The primary function of a Megger is to assess the insulation quality of conductors, cables, motors, transformers, and other electrical devices. It measures the resistance of the insulation between two conductive points, typically between a live conductor and ground or between two separate conductors. By measuring insulation resistance, the Megger helps identify potential insulation faults, such as deteriorated or damaged insulation, moisture ingress, or improper installation.

Meggers use high DC (direct current) voltage, typically ranging from a few hundred volts to several thousand volts, to stress the insulation system and measure its resistance. The instrument applies the voltage and measures the resulting current flowing through the insulation. Based on Ohm’s law (V = I × R), the Megger calculates the insulation resistance, which is displayed on a digital or analog scale.

Modern Meggers often come with additional features such as auto-ranging, automatic discharge after testing, data logging capabilities, and compatibility with computer software for data analysis and reporting. They may also include safety features like voltage limiters, warning indicators, and rugged construction to withstand harsh working conditions.