Find the fault point in three steps.
The excavator is not working. Recently, a DH220LC excavator owner was very troubled. After his excavator worked at the construction site for a day, when he was preparing for construction work the next morning, he found that it could not run and the appearance did not look good.
The reason came out. Due to the tight construction schedule, the equipment immediately contacted the maintenance man who repaired the excavator. The maintenance personnel arrived at the scene for a simple inspection and inspection. They found that the starter was damaged, so they proposed to the equipment to replace the starter. After the starter was replaced, the excavator also ran successfully. There were no problems with the operation after several tests, and the equipment was very satisfactory.
After paying the maintenance fee, the maintenance personnel left and the excavator continued to work. This time the equipment was thought to be in good luck, but after the excavator had been working for a period of time, it failed to start again after shutting down. This time the equipment was particularly cautious and called in the after-sales service staff of the excavator manufacturer.
Fault analysis is first based on experience. The machine repeatedly fails to start, and a similar situation occurs after the starter is replaced.
The cause must be found from the following aspects.
- Is the starter wire connector in good condition?
- Is the connection of the key switch in good condition?
- To check whether the excavator battery relay is working, check whether the connection between A terminal and B terminal is closed after turning on the key switch. If it does not pull in, the reason must be checked.
- Is the starting relay working normally? Use the resistor setting of a digital multimeter to check the PP and B terminals of the start relay. Check the resistors of these two terminals without turning the key switch. If there is no resistor indication on the multimeter, it means that the starter relay is normal. If there is a resistor, it means that the starter relay is faulty, and the PP and B terminals have been closed.
Reason: Due to the burning of the PP and B terminals of the starting relay, the line is often open. After the excavator is started, the operation control panel cannot disconnect the start relay, so that the starter is always supplied with electricity, causing the starter to be running all the time. The gear of the car engine pushes the starter transmission gear to adjust and rotate, causing damage to the starter. This is the so-called follow-up phenomenon.
Solution:
- If the starter does not work, check that all relevant components are normal and replace the starter.
- Check for faults in the starting relay. The starting relay and starter must be interchanged.
To sum up, maintenance personnel should be very careful and attentive when troubleshooting electrical equipment faults. Because electrical equipment problems are invisible and intangible, they are also the most troublesome for maintenance personnel among excavator faults. During maintenance, we need to do adequate monitoring and observation, and do not replace faulty components without doing any inspections. Only through timely inspection and complete cleaning can the fault be eliminated, only in this way can you get praise for yourself, and at the same time, the repair cost and time can be reduced.
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