Switch Vacuum Tester
Darui Electric recommends:
Vacuum Tester. English translation: Vacuum degree reflectoscope reflector The switch vacuum tester uses the magnetron discharge method for measurement. The two contacts of the vacuum switch arc extinguishing chamber are separated by a certain distance，and an electric field pulse high voltage is applied. The arc extinguishing chamber is placed inside a solenoid coil or a new type of electromagneticcoil is placed outside the arc extinguishing chamber, and a large current is passed through the coil, thereby generating a pulsed magnetic field synchronized with the high voltage inside the arc extinguishing chamber. In this way, under the action of the pulsed strong magnetic field and strong electric field, the charged ions in the arc extinguishing chamber move in a spiral motion, and collide with residual gas molecules to cause ionization. The resulting ion current is approximately proportional to the residual gas density, i.e., the vacuum degree.
Instrument Features
1. Can quantitatively measure the vacuum degree inside the arc extinguishing chambers of various types of vacuum switches;
2. No need to disassemble the vacuum switch during on-site measurement;
3. Test results are accurate and reliable;
4. LCD with Chinese character display, making operation simpler and more convenient;
5. Can save, print, and view test data;
6. The instrument is equipped with an RS232 communication interface, which can be connected to a computer to achieve multiple functions such as vacuum degree-ion current curve download and life estimation;
7. Light weight and easy to carry.
8. Achieves non-disassembly measurement of vacuum arc extinguishing chambers, directly displaying the vacuum degree value, enabling vacuum circuit breaker users to grasp the vacuum state of the arc extinguishing chamber in detail, providing a reliable basis for planned replacement of arc extinguishing chambers, offering strong protection for the safe operation of the power grid, and overcoming the defect that the power frequency withstand voltage method can only judge whether the arc extinguishing chamber is scrapped.
◆ Sampling technology based on ionization charge
The vacuum degree tester adopts sampling technology based on ionization charge. In the research of magnetic discharge, it is found that when the external excitation power supply, the geometric dimensions of the vacuum arc extinguishing chamber, and the materials used are fixed, the vacuum degree in the vacuum arc extinguishing chamber has a very accurate corresponding relationship with the amount of ionized charge, while it only has a probabilistic correlation with the peak value of the ionization current. Therefore, the sampling technology based on ionization charge significantly improves the accuracy of vacuum degree measurement of vacuum arc extinguishing chambers.
◆ Handling of leakage current
When high voltage is applied to both ends of a vacuum arc extinguishing chamber in the open state, there will be a leakage current of several microamperes with varying values. This leakage current has significant individual differences even among vacuum arc extinguishing chambers of the same model. Especially for vacuum arc extinguishing chambers installed on the complete machine, the surrounding insulation support parts also have leakage, and the total leakage has greater instability and unpredictability, and its value is comparable to the ionization current of a vacuum arc extinguishing chamber with a vacuum degree of 10E-4 Pa. By using the method of starting the high voltage twice, the leakage current is deducted.
◆ Built-in
Due to differences in geometric dimensions and materials of vacuum arc extinguishing chambers, when the internal vacuum degree and external excitation power supply are fixed, the discharge charge amount is different and has considerable differences. For accurate measurement, each type of vacuum arc extinguishing chamber must have a corresponding calculation curve from ionization charge amount to vacuum degree.
◆ Complete input protection circuit
When the vacuum degree of the vacuum arc extinguishing chamber is very low, the vacuum arc extinguishing chamber will be broken down by high voltage during measurement, and the instantaneous high voltage is directly applied to the sampling circuit at the signal input end, subjecting it to a very strong electrical impact. The sampling circuit at the signal input end of the vacuum degree tester is equipped with a complete protection circuit, so even if the instrument temporarily malfunctions due to high voltage impact at the input end (just restart it), it will not cause damage to the circuit part.
