The Insulation Resistance Tester is commonly known in the power industry as a Megohmmeter or Megger.
The older generation of electricians used to call it the “crank meter” (because early megohmmeters generated high voltage through hand-cranked power generation).
If the previously discussed Online Partial Discharge Tester is like capturing faint “heart murmurs” inside equipment, then the Insulation Resistance Tester is like giving the insulation layer of power equipment a “basic health checkup.” Its core task is to apply a relatively high DC voltage to measure the resistance value of the insulating material when the equipment is de-energized, thereby determining whether the insulation is damp, aged, or at risk of breakdown.
⚙️ Core Applications and Importance
Insulation resistance is the most fundamental and intuitive indicator for evaluating the insulation performance of electrical equipment (such as transformers, motors, cables, surge arresters, etc.).
Core Function: It can detect defects such as moisture, contamination, aging, and cracking in equipment insulation layers in advance. If the insulation resistance value is too low, the equipment is highly prone to leakage, short circuits, and even fires and electric shock accidents during operation.
Wide Application: It is an indispensable routine testing tool in electrical installation, maintenance, and preventive testing, suitable for virtually all electrical equipment and lines with insulation layers.
