Q1: What is a insulation tester?
A1: Insulation tester, also known as megohmmeter or meggers, are widely used to measure cables for generators, motors, power transformers, wiring, appliances and other electrical installations such as control, signal, communication and power ) insulation resistance. They are often used in routine maintenance procedures to indicate changes in the insulation resistance of a motor over months or years. Large changes in insulation resistance may indicate potential failures. Therefore, regular calibration of the megohmmeter is required to ensure that the meter itself has not changed over time.
Q2: What is insulation resistance?
A2: Insulation resistance is the DC resistance of the insulation under the specified conditions, that is, the DC voltage is applied to the dielectric, after a certain period of polarization, the resistance corresponding to the leakage current flowing through the dielectric is called insulation resistance. It is the most basic insulation index of electrical equipment and electrical circuit.
Q3: How to measure insulation resistance?
A3: 1. Connect all the lines according to the method measured by the insulation resistance tester. The connection between the measuring lead and the pipe is more suitable for the use of magnetic joints or clips, and the connection point must be free of rust.
2. The measuring instrument should be a 500V/500MΩ (the error here cannot be greater than 10%) insulation tester. Turn the handle of the megohmmeter to reach the specified speed for 10 seconds. The resistance value indicated by the megohmmeter stably is the insulation resistance value of the insulating joint (flange), which is required to be greater than 10 megohms.
Tips: How to use megger insulation tester?
- Be familiar with the instruction manual of the megger insulation tester, and have a comprehensive understanding of the structure, performance and usage of the digital insulation tester.
- Prepare the necessary tools and all the accessories of the digital insulation tester for the measurement, and wipe the digital insulation tester and the grounding probe clean, especially the grounding probe, be sure to clean the surface of the dirt and rust that affect the conductivity.
- Disconnect the connection point between the grounding trunk line and the grounding body or the connection points of all grounding branch lines on the grounding trunk line, so that the grounding body is separated from any connection and becomes an independent body.
- Insert the two grounding probes into the ground 20m and 40m away from the grounding body along the radiation direction of the grounding body, and the insertion depth is 400mm.
