Abstract : This paper introduces the problems encountered by GE's electronic control system in the application of container yard cranes, and proposes targeted modification solutions to improve system performance to a certain extent. Keywords : Programmable Logic Controller; Frequency Converter I. System Disadvantages The programmable logic controllers (PLCs) series 6 and 90, as well as the thyristor rectifiers DC300 and DC2000 and the IGBT inverter AC2000 produced by General Electric (GE) are early products. This system has the following disadvantages: 1. High operating costs. Container yard cranes are powered by diesel generator sets, and fuel cost becomes the evaluation standard for the electronic control system. Under the same configuration, the GE system consumes 14.7 L/h of fuel, while the Yaskawa I system consumes 12.5 L/h. 2. High heat dissipation of the frequency converter. High heat dissipation is detrimental to the operation of the frequency converter and can easily cause damage, especially in summer, when the ambient temperature must meet the operating requirements of the frequency converter. 3. Expensive spare parts and long procurement cycle. A communication module costs more than 30,000 yuan, and a circuit board costs more than 50,000 yuan. These two components alone incur annual losses exceeding 600,000 yuan, with a procurement cycle lasting up to six months. CE has ceased production of some components. 4. The humid environment of port machinery makes the GE system unsuitable, leading to frequent malfunctions. To address these issues, the following improvements are implemented: II. Replacement of Some Units in the GE Electrical Control System Replace the GE AC200o frequency converter with Yaskawa I 616G5 and 686CR5 frequency converters; replace the 9030 series programmable controller with a CP316H programmable controller; do not replace the motor; replace the speed encoder and supplement with corresponding wiring; update the control relays. III. Targeted Improvements for Original System Faults 1. Programmable Logic Controller (PLC) Series 6 Intelligent Bus Fault: During system operation, loose connections in the communication lines of various modules on the intelligent bus cause instability and disconnection of the control power supply. Measures: First, add terminal blocks to the communication line interfaces of the intelligent modules; second, regularly inspect the module interfaces and bus connections, and check the resistance values ​​at both ends of the intelligent bus. 2. AC2000 inverter 129" fault The inverter often has a 129 fault when it is initially powered on. The fault is an initial power-on check fault. The inverter will only enter normal working state after the central processing unit of the inverter checks that its working voltage (3.3~3.8V) is normal. When the power plug is loose or the pins are oxidized, the central processing unit may not be able to detect the correct voltage value. Solution: Clean and tighten the power plug and pins regularly, and at the same time, perform anti-oxidation treatment on the pins. 3. AC2000 inverter IGBT burnout fault The inverter has a damaged power element IGBT. The reason is that the IGBT heats up quickly when it is working, and the ambient temperature rises; the various connectors of the inverter are loose, which leads to the IGBT control disorder and damage. Corrective measures: (1) Install air conditioning in the electrical room; (2) Add a control delay level to the peripheral control circuit of the inverter to reduce the malfunction caused by loose connectors, and tighten the connectors. IV. Equipment maintenance 1. Strengthen the maintenance of the engine and the inspection of the speed control system. 2. Ensure that the wiring of electrical components is secure and the sockets are clean. 3. Strengthen the maintenance of variable frequency motors. Due to the influence of high-order harmonics, the temperature rise, winding insulation damage and bearing wear of variable frequency motors are higher than those of ordinary asynchronous motors. Therefore, daily maintenance should be done well: (1) Ensure that the motor casing is clean and the cooling air duct is unobstructed; (2) Check noise and insulation; (3) Lubricate according to the requirements of the instruction manual and technical documents. 4. Maintenance of motor accessories, including cleaning of overspeed switches and encoders. After partial rectification and preventive maintenance, the equipment utilization rate has increased from 20% to 50%; the equipment failure time has been reduced from about 15 hours/month to about 3 hours/month.