Degradation Phenomenon and Mechanism Analysis of Action Characteristics of Aviation Contactors

Aiming at the dangerous fault of aircraft generator power failure caused by unstable operation of aviation contactor in aircraft pump station, the degradation phenomenon and mechanism of action characteristics of aviation alternating current (AC) contactors were analyzed. A test platform was built to test the action voltage waveform of the contactor and check the action time and connection status of the contacts. A faulty contactor and a normal contactor of the same model were disassembled. The macro and micro morphologies of the moving and static contacts of the two contactors were observed with a stereo light microscope and a scanning electron microscope, providing evidence for the analysis of contactor failure. The results show that the synchronous time of the contactor contacts exceeds the standard requirement of 2 ms, and the surge current generated by the long-term startup of the contactor pump load is the important reason for the insufficient overload resistance of the contactor to the line system. The harm of the pump load startup surge current to the electrical ablation of contacts should be minimized in the design.