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.
What are the functions of insulation resistance testers?
- Repair faulty parts
Technicians use tests to verify high insulation resistance between conductors and ground or adjacent conductors. By testing the insulation resistance of different components in the system (transformers, switchgear, conductors, motors), technicians can isolate and repair failed components.
- Improve system performance
Before energizing the system, verifying that it is sound using insulation testing can improve the performance of the system.
- Found manufacturing process problems and equipment defects
Insulation testing can uncover manufacturing process problems and equipment defects that would not normally be discovered until the equipment fails. In the EU, the test is mandatory, even for the smallest civilian systems.