大型医疗设备，如CT，加速器，X线影象设备等，多采用三相电源供电。三相电源从公共电网通过各大型医疗设备配电空气开关（或间刀），经过设备专用电源稳压器后向各设备提供较稳定的电源。在这两个环节上的接触不良，可造成设备的电源质量大大下降，轻者影响设备工作稳定性，严 Large-scale medical equipment, such as CT, accelerators, X-ray imaging equipment, and so on, mostly use three-phase power supply. Three-phase power from the public power grid through the major medical equipment distribution air switch (or interval knife), through the device-specific power regulator to provide more stable power to the device. Poor contact between these two links can result in a significant decrease in the power quality of the equipment, and the light affects the stability of the equipment.