Testing principle of vacuum switch vacuum degree tester
The vacuum switch vacuum degree tester uses magnetron discharge method for measurement. Pull apart the two contacts of the vacuum switch arc extinguishing chamber by a certain distance, apply electric field pulse high voltage, place the arc extinguishing chamber inside the solenoid coil or place the new electromagnetic coil outside the arc extinguishing chamber, and apply a large current to the coil to generate a pulse magnetic field synchronized with the high voltage inside the arc extinguishing chamber. In this way, under the action of pulsed strong magnetic field and strong electric field, the charged ions in the arc extinguishing chamber undergo spiral motion and collide with residual gas molecules for ionization. The resulting ion current is approximately proportional to the residual gas density, i.e. vacuum degree.
For different vacuum tube models (tube types), due to their different structures, the magnitude of ion current varies under the same contact distance, vacuum degree, electric and magnetic fields. The corresponding relationship curve between vacuum degree and ion current of various tube types can be calibrated through experiments. After measuring the ion current, the vacuum degree of the tube type can be obtained by querying the ion current vacuum degree curve of the tube type.
When testing the vacuum degree of the arc extinguishing chamber in conventional magnetron discharge, in order to improve its testing sensitivity, the arc extinguishing chamber needs to be removed from the circuit breaker and placed inside the solenoid tube. In this way, the arc extinguishing chamber needs to adjust the mechanical parameters when reinstalling the circuit breaker, which requires a lot of work and professional personnel. The use of a new type of magnetic coil can surround the arc extinguishing chamber from the side, so there is no need to disassemble the arc extinguishing chamber. By using a single-chip microcomputer for synchronous control and data acquisition and processing, the sensitivity of on-site testing of the vacuum degree in the arc extinguishing chamber has been improved.
Working principle of vacuum switch vacuum degree tester test
The vacuum switch vacuum degree tester is composed of a measurement control circuit, an electric field high voltage generation circuit, a magnetic field coil current control circuit, communication, printer, LCD display circuit, etc.
The working process is as follows: the measurement control circuit sends instructions, the switching power supply charges the magnetic field capacitor, and the control circuit monitors it. When the voltage on the magnetic field capacitor reaches the predetermined value, the control circuit sends two control signals to control the output of the electric field high voltage and the conduction of the magnetic field coil current, so that the arc extinguishing chamber is in a strong electric field and strong magnetic field state, and the arc extinguishing chamber begins to discharge, generating ion current I. After passing through the sampling resistor R and preprocessing circuit, the current is input into the microcontroller, and finally the measured vacuum degree value is displayed on the LCD screen through calculation.
Post time:2021-10-28 09:23:22