Current does not always reach its intended destination, even with intact functional insulation, current will be lost all the way. In the real world, there is not always an intact functional insulation. Insulating materials will wear out due to heat, cold, vibration, dust and similar forces. Routine testing allows you to understand whether the electrical system is operating as efficiently and safely as expected, and helps you identify problems before they occur.

Insulation resistance test can provide you with a quantifiable number to estimate the conductor insulation condition of various electrical equipment. It will apply current to the system to be tested, some of which will charge the internal insulation layer. When the electron finds itself When stored in insulating material, the resistance reading on the meter will gradually increase, and your reading (in megohms) will tell you the charging speed of the insulating layer.

Diagnostic role of current

Different testers may apply a variety of different currents. Each current has its own diagnostic purpose. Capacitive current is the initial charge of the current when voltage is first applied. The absorption of charge is high at the beginning, but as the voltage increases However, when it drops slowly, the absorption inside the insulation decreases, which makes the capacitive current an important reflection of energy storage in the insulation.

However, polarization or absorption current will also be absorbed, depending on the degree of damage of the insulation layer you want to check. If the insulation layer is damaged due to moisture, the absorbed current will rise sharply, but it will take longer to establish the polarization current , So a short test using capacitive current may not reveal potential contamination problems.

For the most accurate maintenance and troubleshooting applications of insulation resistance testers (also called digital insulation resistance meters), in addition to capacitive charge tests, you also need polarization and absorption tests. Some resistance testers are equipped to perform all these types of currents. The ability to test, while others only specifically test one.