Insulation resistance tester, usually called megger or megger, is widely used to measure the insulation resistance of generators, motors, power transformers, lines, electrical appliances and other electrical equipment (such as cables for control, signal, communication and power supply). They are usually used in routine maintenance procedures to indicate the change of motor insulation resistance in several months or years. A large change in insulation resistance may indicate a potential fault. Therefore, it is necessary to calibrate the megohmmeter regularly to ensure that the meter itself has not changed with time.
The insulation resistance of general materials decreases with the increase of ambient temperature and humidity. Relatively speaking, surface resistance (rate) is more sensitive to environmental humidity, while bulk resistance (rate) is more sensitive to temperature. With the increase of humidity, the surface leakage increases, and the conductor conduction current also increases. With the increase of temperature, the movement speed of carriers will be accelerated, and the absorption current and conductance current of dielectric materials will also increase accordingly. According to relevant data, the resistance of dielectric at 70℃ is only 10% of that at 20℃. Therefore, when measuring insulation resistance, it is necessary to indicate the temperature and humidity when the sample is in equilibrium with the environment.
The fastest detection time of Kaya HIOKI insulation resistance tester ST5520 is 50ms(0.05s), achieving the fastest speed in the industry. Compared with the previous product (3 154), the detection time is 500ms(0.5s), and the detection speed is increased to 10 times. In addition, in order to prevent the outflow of defective products, a contact inspection function is installed to improve the inspection quality.