When the vacuum degree of the arc extinguishing chamber of a vacuum switch tube deteriorates to 10⁻²–10⁻¹ Pa, although the breakdown voltage has not significantly decreased, the arc extinguishing capability no longer meets operational requirements. On-site judgment requires the magnetron discharge method to measure vacuum degree. The WDZK-5 switch vacuum degree tester adopts a magnetron coil sampler and is configured with a 1600V magnetic field voltage, suitable for vacuum degree detection of various types of vacuum switch tubes.
The internal vacuum degree of a vacuum switch tube cannot be directly observed. Conventional withstand voltage tests can only reflect the breakdown voltage, while an arc extinguishing chamber that has deteriorated to the 10⁻²–10⁻¹ Pa range may still pass the withstand voltage test, leading to missed detection of hidden hazards. O&M personnel need a detection method that can quantitatively measure vacuum degree, adapt to different models of switch tubes, and has a clear operating procedure.
The WDZK-5 is based on the magnetron discharge principle: the arc extinguishing chamber is placed in an axial magnetic field generated by a magnetron coil, high voltage is applied to ionize residual gas, and the ion current is measured and converted into vacuum degree. The instrument has built-in calibration curves, and corresponding samplers can be selected for different tube types. The detection object covers various models of vacuum switch tubes. The magnetic field voltage is 1600V, meeting the excitation requirements of conventional arc extinguishing chambers; the sampler adopts a magnetron coil structure, facilitating on-site clamping installation.
Before testing, confirm that the switch tube is in the open position and disconnect the primary circuit; select a matching magnetron coil according to the tube diameter and ensure tight fit; after setting the magnetic field voltage, start the measurement and read the vacuum degree value. If the measurement result falls in the 10⁻²–10⁻¹ Pa range, whether to replace should be comprehensively judged in combination with the historical data and operating conditions of the arc extinguishing chamber.
Suitable for vacuum degree detection of vacuum circuit breaker arc extinguishing chambers in substations, switchgear manufacturing plants, and maintenance workshops, and can be used for batch screening of multiple switch tubes in conjunction with power outage maintenance plans.
