Phenomenon 1: Air preheater A main motor trips. 2: Air preheater A auxiliary motor trips. 3: Air preheater A outlet flue gas temperature rises, outlet primary/secondary air temperature drops. Handling: 1. Air preheater A trips and alarms; check and see if the standby motor trips again after self-starting. Try to restart the main/auxiliary motor once, but it fails to start. Report to the shift supervisor, instructing the inspector to manually operate air preheater A on-site. Contact maintenance support. 2. Manually stop one E(C) mill, quickly reduce the load to 300MW, target pressure 14MPa. 3. Close the flue gas inlet damper, secondary air outlet damper, and primary air outlet damper of air preheater A. 4. Remove the air preheater sector plate. 5. Contact the assistant to monitor the turbine and electrical systems. 6. Check the operating B-side air preheater; all parameters of the forced/induced draft fan and primary air fan are normal, oxygen content and negative pressure are normal. 7. Check that the pulverizing system is operating normally, furnace combustion is normal, and flame detectors are normal. 8. Monitor the main/reheat steam and wall temperature. Superheat should be normal. Manually adjust the coal/water ratio and flue dampers if necessary. 9. Check that the feedwater/condensate system is operating normally, with normal flow and water level. 10. Check the local condition and switches of the main/auxiliary motors of air preheater A.