Detection Technology
Several methods of circuit breaker testing
1) Use electromagnetic oscillator or drum instrument. When the early oil switches were tested for characteristics, the electromagnetic oscillator was connected to the pencil fixed on the moving contact rod, and the pencil was driven to swing horizontally at a frequency of 100 Hz during the opening and closing process of the switch. With the movement of the rod, the fixed The oscillating wave of travel time is outlined on the cardboard with coordinates. In addition, it can also be tested with a drum instrument. The principle is that the drum instrument is designed to take 1ms for every 1mm of rotation on the drum surface. During the measurement, the switch moves the contact to drive the stylus to move up and down. Or opening curve. The marker used in these two methods is essentially equivalent to a displacement sensor, which is simple and convenient, but it is affected by various factors and is likely to cause larger measurement errors.
2) Use the sliding wire rheostat to cooperate with the light oscilloscope for characteristic test. The sliding wire rheostat is composed of a wire wound resistor and a sliding contact. The sliding contact is fixed on the moving contact rod. A certain voltage is applied to both ends of the wire wound resistor. By recording the sliding wire resistance voltage that moves with the moving contact rod, Cooperate with oscilloscope to get the waveform curve of travel time and related travel and speed data. The disadvantage of this method is that it is troublesome to adjust, and it lacks sufficient support for the extended analysis of mechanical characteristic curves.
3) Use grating displacement sensor (grating ruler) as the intelligent comprehensive test method of displacement sensor. With the continuous advancement of computer technology and sensor technology, circuit breaker mechanical characteristic testing equipment has gradually developed into an intelligent, digital, and graphical comprehensive testing tool, and at this time, most sensors also use grating rulers. The grating ruler generally uses a grating engraved on a certain carrier (such as glass, crystalline ceramic or steel tape, etc.) as a reference for measurement. Its working principle is to use a photocell scanning method that senses changes in luminosity to measure. The grating ruler has strong anti-interference and high sensitivity, but it is easily damaged during testing or storage. Many users gradually switch to linear or angular sensors.
4) At present, using linear sensors (sliding wire rheostats) or angle sensors (angle potentiometers) to perform intelligent characteristic detection with a microcomputer-based switch characteristic tester has become a popular test method. The test is intuitive, accurate, and reliable. The operability is far better than the non-electrical sensors in the early stage.
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