Use of insulation resistance tester and multimeter
Insulation resistance meter, commonly known as megohmmeter, or shaking meter, high resistance meter, insulation resistance tester, etc. Insulation resistance meter is a widely used detection instrument for insulation resistance in power websites and electrical equipment. The insulation properties of electrical products are reflected through insulation resistance.
1. Why do we need insulation resistance testing?
An electrical system is like a piping system, voltage is like liquid pressure, current is like liquid flow rate, and electrical insulation is like pipe walls. Insulation prevents electronic leakage from conductors - the magnitude of its effect is represented by insulation resistance. An effective insulation resistance system has a high resistance value, typically greater than a few megaohms (M Ώ). Poor insulation systems have lower insulation resistance.
In order to detect leaks in the pipeline system, it is necessary to apply pressure. Due to the high water pressure, it is easier to detect leaks, so it is not possible to turn off tap water to check for leaks. However, the available tap water can be restricted so that too much water is not sprayed around when large leaks are detected. An ideal test would be to provide a limited amount of water under high (but not particularly high) pressure. This is exactly what an electrical insulation tester needs to do.
The insulation tester (megohmmeter) applies a direct current voltage to the insulation system and measures the resulting current. This allows for the calculation and display of the insulation resistance value (the degree to which insulation confines current in the wire, or prevents current leakage).
1. Instructions for using a multimeter
1) The selection of terminal buttons (or sockets) should be correct
The red probe connecting wire should be connected to the red terminal (or the socket marked with a "+" sign), and the black probe connecting wire should be connected to the black terminal (or the socket marked with a "-" sign). Some multimeters are equipped with AC/DC 2500 volt measuring terminals, and when in use, the black test rod should still be connected to the black terminal (or the socket marked with a "-" sign), while the red test rod should be connected to the 2500 volt terminal (or the socket marked with a "-" sign).
2) The selection of the switch position should be correct
Turn the conversion switch to the desired position according to the measurement object. If measuring current, the conversion switch should be turned to the corresponding current range, and the measured voltage should be turned to the corresponding voltage range. Some multimeters have two toggle switches on the panel, one to select the measurement type and the other to select the measurement range. When using, the measurement type should be selected first, and then the measurement range should be chosen.
3) The range selection should be appropriate
According to the approximate range being measured, turn the conversion switch to the appropriate range for that type. When measuring voltage or current, it is recommended to keep the pointer within the range of half to two-thirds of the measuring range for more accurate readings.
4) Read correctly
There are many scales on the dial of a multimeter, which are suitable for different measured objects. Therefore, when measuring, while reading on the corresponding scale, attention should also be paid to the coordination between the scale reading and the range range range to avoid errors.
