[Summary description] The analysis process of electrical faults is the process of troubleshooting. Therefore, some common troubleshooting methods for electrical faults have been comprehensively introduced in the above analysis methods. Here are a few common electrical faults.
The analysis process of electrical faults is the process of troubleshooting. Therefore, some common troubleshooting methods for electrical faults have been comprehensively introduced in the above analysis methods. Here are a few common electrical faults.
(1) Power supply The power supply is the energy source for the maintenance system and even the normal operation of the entire machine tool. Its failure or failure will cause data loss and shutdown at the least. In severe cases, it will destroy part or even all of the system. Western countries have sufficient electricity and high-quality power grids, so their electrical system power supply design is less considered. This is slightly insufficient for my country’s power supply grid with large fluctuations and high-order harmonics. Coupled with certain human factors, it is inevitable that faults caused by power supply will occur. When designing the power supply system of CNC machine tools, we should try our best to do the following:
① Provide an independent distribution box instead of using it in series with other equipment.
② Areas with poor power supply quality should be equipped with three-phase AC voltage stabilization devices.
③ The power supply has good grounding at the beginning.
④ The three-phase power supply entering the CNC machine tool should adopt a three-phase five-wire system, and the neutral line (N) and the ground (PE) should be strictly separated.
⑤ The layout of the electrical components in the electrical cabinet and the laying of AC and DC wires should be isolated from each other.
(2) Position loop failure of the CNC system
① Position loop alarm. It may be that the position measurement loop is open; the measuring element is damaged; the interface signal established by the position control does not exist, etc.
② The coordinate axis moves without instructions. It may be that the drift is too large; the position loop or speed loop is connected as positive feedback; the feedback wiring is open; the measuring element is damaged.
(3) The machine tool coordinates cannot find the zero point. It may be that the zero direction is far away from the zero point; the encoder is damaged or the wiring is open; the grating zero mark is shifted; the return to zero deceleration switch fails.
(4) The dynamic characteristics of the machine tool deteriorate, the workpiece processing quality decreases, and even the machine tool vibrates at a certain speed. One of the most likely reasons is that the gap in the mechanical transmission system is too large or even seriously worn, or the guide rail is not lubricated enough or even worn; for the electrical control system, it may be that the speed loop, position loop and related parameters are no longer in a matching state, and they should be re-adjusted after the mechanical fault is basically eliminated.
(5) Occasional shutdown failure. There are two possible situations here: one is that the shutdown failure under certain specific operation and function operation combinations is caused by problems in the related software design as mentioned above. Generally, the shutdown failure will disappear after the machine tool is powered off and then powered on again; the other is caused by environmental conditions, such as strong interference (power grid or peripheral equipment), high temperature, high humidity, etc. This environmental factor is often ignored by people. For example, in the southern region, machine tools are placed in ordinary factory buildings or even near open doors, the electric cabinet is opened for a long time, and there are a large number of equipment that generates dust, metal chips or water mist nearby. These factors will not only cause failures, but also seriously damage the system and machine tools. Be sure to pay attention to improvement.
