Faults can be classified into actual and potential ones according to their online appearance. Actual fault is also known as functional fault, because of the actual existence of this fault, the original hydraulic system can not work or work ability is significantly reduced, such as the key hydraulic components are damaged; A potential fault, similar to a delayed fault, has not been demonstrated in terms of functionality, but its potential can be measured by observation and instrumentation.
Failure according to the cause of occurrence, can be divided into artificial and natural two. Due to design, manufacture, operation installation, use and maintenance
Fault caused by improper fault are called artificial fault; Due to irresistible natural factors (such as wear, corrosion, aging and environmental factors) caused by the fault are natural fault scope.
The failure rate of hydraulic equipment is generally higher in the initial stage due to design, manufacturing, transportation, installation, debugging and other reasons. With the extension of the operation time and the continuous elimination of the fault, the failure rate will gradually reduce. In the late stage of equipment use, due to long-term use of wear and tear, corrosion, aging, fatigue and so on and gradually make the fault increase. Only in the middle period of use, the equipment failure tends to random stable period, that is, the effective working life of the equipment. However, if the potential fault is not diagnosed and eliminated in time due to improper use or failure, it is not possible to eliminate all kinds of sudden serious faults even in the effective life. Therefore, it is the premise of correct and timely troubleshooting to study and summarize the equipment faults and diagnostic techniques.