Exam Question

A Megger, often referred to as an insulation resistance tester, is a portable instrument used for measuring the electrical insulation resistance of electrical cables, motors, generators, switchgear, and other electrical equipment. Its primary purpose is to identify degradation in insulation, which can lead to leakage currents, short circuits, and potential electrical hazards. The device applies a high DC voltage across the insulation and measures the resulting small leakage current to determine the insulation resistance.
### (a) Explanation of the Working of a Megger with the Aid of its Internal Circuit
#### 1. Purpose and Principle:
The Megger operates on the principle of applying a high DC voltage to an insulation system and then measuring the very small current that flows through or across the insulation. By Ohm's Law ($$ R = V/I $$), the insulation resistance (R) can be calculated. The higher the insulation resistance, the better the insulation quality.