Poor contact of air compressor power causes electron microscope to shut down

There are seven valves in the vacuum system of the transmission electron microscope. The valves are driven by compressed air: their actions are driven by the solenoid directional valve to drive the cylinder, and the cylinder then drives the valve to close and open. Recently, this electron microscope caused a fault that caused the electron mirror to automatically shut down during operation due to the leakage of the solenoid reversing valve and the poor contact of the air compressor power supply. The brief introduction of the situation is as follows. Symptoms: In the one-time operation, the electron microscope automatically shuts down; on the display, the compressed air pressure is insufficient. Failure inspection and burial: The compressed air pressure is insufficient due to the cause of the fault. Therefore, check the air compressor first and find that the overload protector of the air compressor itself has been activated. After the switch is reset, the instrument is working properly.

However, the above-mentioned failure phenomenon occurred again and again on the second day. The working current of the air compressor was measured with a clamp meter at 5A, which was within the normal range. The main body of the electron microscope was turned off, and the air compressor was repeatedly inflated and deflated. The air compressor was found to be stalled when the pressure switch was turned on, causing the overload protector of the air compressor to act. At this time, the air compressor motor input was measured. The voltage is only 80V. At this time, the output voltage of the air compressor power supply transformer is 95V, and the voltage drop of 15V on the power transmission transformer to the air compressor less than two meters long is obviously abnormal. Based on this, inspecting the air compressor power plugs and sockets found traces of burnt black copper on the socket; at the same time, it was found that the cable connecting the power transformer to the air compressor socket has a cross-sectional area of ​​only 0.5 mm2. Replace the cable with a 2.5 mm2 cross-sectional area cable. Replacing the socket, the air compressor can't start the troubleshooting process, and the compressed air pressure of starting and stopping is within the normal range.