When substation operation and maintenance personnel conduct routine inspections of vacuum switches, they often need to determine whether the vacuum degree inside the arc-extinguishing chamber is still within the normal range. A decrease in vacuum degree will reduce the breaking capacity of the switch, but this change cannot be directly observed from the appearance. The HM6070 series vacuum degree tester for vacuum switches provides operation and maintenance personnel with a technical means to evaluate the vacuum degree without disassembling the switch by detecting parameters such as ion current.
Typical Usage in On-Site Inspections
During power-off maintenance or handover tests of switchgear, operation and maintenance personnel can connect the high-voltage output terminal of the tester to the moving and fixed contacts of the vacuum switch tube, and complete pressurization and measurement according to the instrument prompts. The tester usually displays the value of the ion current, and operation and maintenance personnel need to pay attention to whether this value falls within the range of historical data. If there is an obvious deviation from the previous measurement, the measurement should be repeated once to eliminate factors such as poor contact or environmental interference. Different models of vacuum switch tubes may have different correspondences between ion current and vacuum degree, so during procurement it is necessary to confirm whether the instrument supports calibration or curve settings for specific tube types.
Parameter Checklist During Procurement
When faced with vacuum degree testers of different specifications, procurement personnel can first start with the detection target and confirm whether the instrument covers the various models of vacuum switch tubes used on site. Second, pay attention to the ion current measurement range. Common instruments can achieve a resolution of 10-5 Pa, but the specific range needs to match the vacuum degree interval of the actual switch tube. In addition, it is necessary to understand whether the instrument has a magnetic field control method, measurement repeatability indicators, and on-site power supply conditions. For scenarios requiring rotation among multiple substations, the instrument's portability, battery life, and anti-interference capability are also items to check.
Precautions for Use and Maintenance
After long-term use of the tester, the insulation performance of the high-voltage output cable and connectors may decrease, so regular inspection is recommended. During measurement, ensure that the contact surfaces are clean to avoid the oxide layer affecting the current path. The instrument should be stored in a dry environment to prevent dust from entering the high-voltage module. For procurement personnel, confirming the calibration cycle and after-sales service method with the supplier helps ensure that the instrument remains usable over multiple maintenance cycles.
