The actual resistance value can be measured by connecting the two test leads (not positive or negative) to the two ends of the resistor. In order to improve the measurement accuracy, the range should be selected according to the nominal value of the measured resistance. Due to the nonlinear relationship of the ohmic scale, its middle section is finer. Therefore, the pointer indication value should fall as far as possible to the middle position of the scale, that is, within the range of 20% to 80% radians of the full scale, so that The measurement is more accurate. Depending on the level of resistance error. Errors of ±5%, ±10%, or ±20% are allowed between the reading and the nominal resistance, respectively. If it does not match, if the error range is exceeded, the resistance value is changed.
Note: When testing, especially when measuring the resistance of tens of kΩ or more, do not touch the conductive part of the test leads and the resistor; the detected resistance is soldered from the circuit, at least one head should be soldered to avoid the circuit. Other components have an influence on the test, resulting in measurement error; although the resistance of the color ring resistor can be determined by the color circle mark, it is better to test the actual resistance value with a multimeter when using it.
(2) Detection of the fuse resistor
In the circuit, when the fuse resistor is melted and disconnected, it can be judged according to experience: if the surface of the fuse resistor is found to be black or burnt, it can be concluded that its load is too heavy, and the current passing through it exceeds the rated value many times; If the surface is open without any trace, it means that the current flowing is just equal to or slightly larger than its rated blown value. The judgment of the fuse resistor with no trace on the surface can be measured by the multimeter R×1 block. To ensure accurate measurement, one end of the fuse resistor should be soldered from the circuit. If the measured resistance is infinite, it means that the fuse resistor has failed open circuit. If the measured resistance value is far from the nominal value, it indicates that the resistance value is not suitable for reuse. In the maintenance practice, it is found that a small number of fuse resistors are broken through in the circuit, and attention should be paid to the detection.
High Voltage Epoxy Resin Insulator
Insulators can be divided into low-voltage insulators and high-voltage insulators according to different voltage levels. High voltage insulator refers to the insulator used for high voltage and ultra-high voltage overhead transmission lines and substations. In order to meet the needs of different voltage levels, different numbers of single (piece) insulators of the same type are usually used to form insulator strings or multiple insulation poles.
Epoxy resin material has a series of outstanding advantages in organic insulation materials, such as high cohesion, strong adhesion, good flexibility, excellent heat curing performance and stable chemical corrosion resistance. It can be made into various solid materials by vacuum casting through epoxy resin casting system, such as automatic epoxy pressure gel manufacturing process (APG process). The epoxy resin insulation parts made of the epoxy resin have high mechanical strength, strong arc resistance, high compactness, smooth surface, good cold resistance, good heat resistance, good electrical insulation and other advantages, and are widely used in the power industry, mainly playing a supporting and insulating role.
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