The insulation resistance tester, namely the intelligent dual-display insulation resistance tester (two gears), adopts an embedded industrial microcontroller real-time operating system, perfectly combining digital analog pointer and digital segment display. This series of meters has multiple voltage output levels (250V, 500V, 1000V, 2500V, 5000V, 10000V), large capacity, strong anti-interference, synchronous display of analog pointer and digital, AC/DC dual-use, simple operation, automatic calculation of various insulation indicators (absorption ratio, polarization index), and various measurement results have power-off protection features. It is an ideal testing instrument for measuring insulation resistance of large-capacity transformers, transformers, generators, high-voltage motors, power capacitors, power cables, lightning arresters, etc.

    Insulation resistance tester editor

The insulation resistance tester is also called digital insulation resistance tester, megohmmeter, intelligent insulation resistance tester, etc.



An electrical system is like a piping system, voltage is like liquid pressure, current is like the flow rate of liquid, and electrical insulation is like the pipe wall. Insulation prevents electrons from leaking from the conductor – its effectiveness is expressed by insulation resistance. An effective insulation resistance system has a high resistance value, usually greater than a few megohms. A poor insulation system has a lower insulation resistance.



2 Product Introduction Editor

The intelligent dual-display insulation resistance tester (two gears) adopts an embedded industrial microcontroller real-time operating system, perfectly combining an ultra-thin tension wire meter head with a graphic dot matrix LCD display. This series of meters has multiple voltage output levels (500V, 1000V, 2500V, 5000V), large capacity, strong anti-interference, synchronous display of pointer and digital, AC/DC dual-use, simple operation, automatic calculation of various insulation indicators (absorption ratio, polarization index), and various measurement results have power-off protection features. This series of intelligent dual-display insulation resistance testers is an ideal testing instrument for measuring insulation resistance of large-capacity transformers, transformers, generators, high-voltage motors, power capacitors, power cables, lightning arresters, etc.



3 Working Principle Editor

  Insulation testers, often called megohmmeters or high-resistance meters, are widely used to measure the insulation resistance of generators, motors, power transformers, wiring, electrical appliances, and other electrical devices (such as cables for control, signal, communication, and power). They are often used in routine maintenance procedures to indicate changes in insulation resistance of motors over months or years. A large change in insulation resistance may indicate a potential fault. Therefore, it is necessary to regularly calibrate the megohmmeter to ensure that the instrument itself has not changed over time.



        The megohmmeter measures resistance by exciting the device under test or network with a voltage, then measuring the current generated by the excitation, using Ohm's law to measure the resistance. A good megohmmeter calibrator includes various optional resistors, which is not much different from modern calibrators that use synthetic resistance functions to provide resistors. The difference between megohmmeter calibrators and DC/low-frequency calibrators lies in the range of resistors required and the voltage withstand capability. For example, compared to the ohmmeter function on a digital multimeter (DMM), these electrical testers apply a much higher voltage when measuring resistance. The voltage range used by megohmmeters typically ranges from 50V up to 5 kV; while typical digital multimeters use voltages generally less than 10 V. For insulation testing, the resistance value range that needs to be measured is very large, with an upper limit up to 10TΩ, requiring higher voltages..