eristysmittari

Eristysmittari, also known as an insulation tester or megohmmeter, is an instrument used to measure electrical resistance, specifically the high resistance of electrical insulation. It operates by applying a high voltage to the insulation and measuring the resulting current. The higher the resistance, the lower the current, indicating good insulation. Conversely, a low resistance suggests a fault or deterioration in the insulating material, potentially leading to electrical leakage or short circuits.

These devices are crucial for electrical safety and maintenance. They are used in a variety of applications, including testing the insulation of electric motors, generators, transformers, cables, and switchgear. By regularly performing insulation resistance tests, potential problems can be identified before they cause equipment failure or safety hazards. Eristysmittarit typically have a hand crank or battery-powered generator to produce the necessary high DC voltage, which can range from hundreds to thousands of volts depending on the application. The results are usually displayed on an analog or digital meter, often in megaohms (MΩ) or gigaohms (GΩ).