What is the primary function of a megohmmeter?

The primary function of a megohmmeter, also known as an insulation resistance tester, is to determine the insulation resistance of electrical equipment such as motors, transformers, and alternators. When used to test alternator windings, the megohmmeter applies a high voltage across the insulation to ensure that it can withstand this stress without allowing current to leak through. This is essential for preventing electrical failures and ensuring the reliability of the equipment.

This testing helps to identify any deterioration or breakdown in insulation that could lead to short circuits or other electrical issues. A megohmmeter typically measures resistance in megohms, allowing technicians to ascertain the health of the insulation and, by extension, the longevity and safety of the equipment being tested.