What are the fault checking methods for electrical equipment of CNC machine tools?
Time:
2019-07-10
When an industrial machine has an electrical fault, it should not be blindly and manually repaired. First of all, the CNC machine operator or the person present at the time of the fault is asked about the fault phenomenon.
1. Fault investigation before maintenance
When an industrial machine has an electrical fault, it should not be blindly and manually repaired. First of all, the CNC machine operator or the person present at the time of the fault is asked about the fault phenomenon. It is the first time that it suddenly occurs, or occurs frequently, the fault occurs, whether the external phenomenon has smoke, flashover, abnormal sound, the surrounding environment when the fault occurs, whether there is any Gas, whether corrosive gas is corroded, whether there is water leakage, whether the heat source causes electrical damage, etc.; whether it has been repaired, the contents of the repair, what operations and malfunctions.
Because the operator of CNC machine tools is most familiar with the performance of this CNC machine tool, it is also the first to understand the possible causes and parts of the fault, which is beneficial to the CNC machine tool maintenance personnel to judge the scope of the fault and analyze the fault based on the relevant working principle. Causes.
Before the inspection, you can understand the operation situation before and after the fault and the abnormal phenomenon after the fault occurs by asking, watching, listening and touching, so as to judge the fault occurrence location according to the fault phenomenon, and then accurately eliminate the fault. Q: Ask the operator about the operation status of the circuit and equipment before and after the fault and the symptoms after the fault occurs. Whether the fault occurs frequently or occasionally; whether there are signs such as noise, smoke, sparks, abnormal vibration, etc. Large and frequent start, stop, brake, etc.; whether there is maintenance or repair or modification of the line. Look: Check whether there are obvious signs of appearance before the failure, such as various signals; the condition of the fuse with the indicating device; the tripping action of the protective device; the disconnection of the wire; the singeing or welding of the contact; the overheating of the coil. Listen: Under the premise that the line can still run and not damage the equipment, you can power on the test, and listen carefully to the sound of electrical appliances such as motor contactors and relays. Touch: After cutting off the power supply, touch the motor, transformer, solenoid and fuse as soon as possible to see if there is overheating.
Through the above investigation, we have a preliminary understanding of the phenomenon of the fault, which reflects various fault problems, and the fault phenomenon and the fault type are one-to-one correspondence. As long as we can grasp the signs reflected by the phenomenon, it is not difficult to find Found the fault.
2. Determine and narrow the fault range by logic analysis
According to the understanding and understanding of the fault phenomenon, further classify the electrical fault phenomenon, and clarify whether the fault is in the motor part, the main circuit part, or the control circuit part fault, or the fault of the control electrical component itself.
3. Find and determine the fault point according to the fault range.
After determining the possible range of the fault, it is necessary to further determine the fault point. To find the fault point, a correct and effective method must be applied.
3.1 Visual inspection of the fault range
After determining the possible range of the fault, visual inspection of the electrical components and connecting wires in the range, for example: melt blown of the fuse; loose or loose wire joint; contact or contact of the contactor and relay, When the coil is burnt out, the surface insulating paper is burnt and discolored, and the burnt insulating varnish flows out; the spring is detached or broken; the action mechanism of the electrical switch is blocked and the like, and the fault point can be clearly indicated.
3.2 Determine the point of failure by means of a power-on test run
When the fault is not detected by the visual inspection, the fault may be analyzed according to the fault phenomenon and the circuit diagram is used to confirm that the fault will not be further expanded and the personal and equipment accidents may occur. In order to more accurately understand the possible causes, the power test can be performed. Check (remove the load wiring if necessary) to distinguish whether the fault may be in the electrical part or in other parts of the machine; on the motor or on the control device; on the main circuit or on the control circuit, under normal circumstances Check the control circuit. The specific method is as follows: When a button or switch is operated, the relevant contactors and relays in the line will work in the specified sequence of actions. If you move to an electrical component in sequence, it is found that the action does not meet the requirements, indicating that the electrical component or its related circuit has a problem. Then in this circuit to carry out item-by-item analysis and inspection, generally can find faults. After the fault of the control circuit is restored to normal, the main circuit is turned on, the control effect on the main circuit is checked, and the operation of the main circuit is observed for abnormality.
3.3 According to the fault range, the fault is determined by detection
When the fault range belongs to a certain part, the instrument, the instrument and the corresponding detection method are further used to further narrow the fault from a larger range and finally determine to the fault point.
Article link: China Machine Tool Business Network http://www.jc35.com/news/detail/56742.html
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