What is vacuum testing instrument
Vacuum circuit breaker is a high-voltage electrical appliance widely used in power system. Its core component is vacuum interrupter. Because the interrupter is based on vacuum conditions, the vacuum tester is not as easy to detect its quality as oil switch and SF6 switch. Traditionally, power frequency withstand voltage method is used to judge the vacuum degree of the interrupter by vacuum circuit breaker users, which can only roughly judge the interrupter with serious vacuum degree.
The vacuum tester is the equipment to evaluate the vacuum degree of the vacuum interrupter. It is based on the principle of magnetic controlled discharge, with a single-chip computer as the main control unit. The test process is fully automated.
In the design of the instrument, the peak current is used to calibrate instead of the ion charge. In this way, the interference of transient power supply in the test process is effectively suppressed, and the test is stable and reliable. Because the computer is used as the main control unit, the instrument can easily deduct the leakage current caused by environmental factors.
The most outstanding features of vacuum measuring instrument:
It realizes the measurement of vacuum interrupter without disassembly, and the vacuum tester directly displays the vacuum value, which enables the vacuum circuit breaker users to master the vacuum state of the interrupter in detail, provides a reliable basis for the planned replacement of the interrupter, provides a strong guarantee for the safe operation of the power grid, and overcomes the defect that the power frequency withstand voltage method can only judge whether the interrupter is scrapped.
The instrument has the advantages of high measurement accuracy, simple operation, convenient carrying and strong anti-interference ability, which is especially suitable for the field test of power supply units. It is one of the necessary instruments for the production, installation, commissioning and maintenance of vacuum circuit breakers.
Use of vacuum tester:
1. The instrument is a precision instrument, circuit board wiring density is large, generally required to be stored in a dry place. If the environment is humid,Power on frequently.
2. If the current value shows zero after the test, check whether the surface of the arc extinguishing chamber is clean. Because the surface is not clean, the change value of the leakage may be greater than the ionization current value. In this way, the measured value minus the leakage is less than zero, and is judged as zero by the instrument. After this happens, wipe the surface of the arc extinguishing chamber clean, and then conduct the test. Generally speaking, the vacuum value obtained in this way is more accurate.
3. During use, the high-voltage output line shall not touch the human body to prevent electric shock.
4. When the high voltage indicator light is on, do not touch the high voltage line and magnetic control current line to prevent electric shock.
5. Dismantle the printing paper when the instrument is powered off first, so as not to damage the printer. When the vacuum tester changes paper, open the front panel, pinch the two ends of the printer with the index finger and thumb, gently pull the two clips out of the printer, so that the paper outlet is slightly higher than the instrument panel, but the distance cannot be too large, cut the new paper port into a pointed shape, insert it into the paper inlet of the printer, turn on the power switch of the instrument, press the print key, so that the paper will come out of the upper end of the printer for a section Distance, insert the exit seam of the panel to export, cover the printer panel, and load the paper.
6. There are no user serviceable parts for this instrument. In case of any failure, please ask professional personnel for maintenance or contact with the supplier. Do not open the instrument without permission to avoid accidents or unnecessary losses.
7. The measurement range of vacuum degree of the instrument is 9.999 × 10-1 ~ 1 × 10-5, and the measurement range of ion current is 9.999 × 10-1 ~ 1 × 10-7. When the vacuum degree of the real empty tube is greater than 10-2 PA or the ion current is greater than 500 UA, the vacuum tube is recommended to be scrapped.
8. If the pressure in the vacuum tube is equal to atmospheric pressure (i.e. the vacuum tube is damaged), the instrument refuses to test within the measuring range of this instrument and returns to the initial state.
matters needing attention：
1. After breakdown, the instrument may display abnormally. At this time, press "reset" key to return the instrument to normal state.
2. The gas pressure of vacuum interrupter used for assembling vacuum circuit breaker shall be less than 1.33 × 10-3 Pa;
3. Within the specified service life, the vacuum degree in the switch tube shall not be higher than 6.6 × 10-2 PA.