The electricity consumption and industrial electricity consumption of our country are all using different power grids.However,due to the large amount of electricity used in the industry,the voltage fluctuation of the industrial power grid is large,and the frequency of the power failure of the CNC system is high.Pay enough attention to it.The power supply is the energy supply part of the circuit board,the power supply is not normal,and the operation of the circuit board is inevitably abnormal.What are the common faults in CNC machining CNC machine tools?
1,fuse blown
If the fuse is black and spotted when it is blown,it indicates that the line has a serious short circuit.It is caused by obvious failure of high voltage filter capacitor breakdown and rectifier tube breakdown.If the fuse is not black,it is slowly blown and can be measured statically.Generally,one of the half bridges is broken or defective.
2,the fuse is continuous,the output is no voltage
In this case,first check if there is a DC voltage of 300V.If not,the fault occurs before the inverter;if there is 300V high voltage and no output,then the oscilloscope can be used to check whether the collector of the switch tube has a 20kHz waveform.If the switch is broken or does not rise.The open circuit of the high-frequency transformer can cause the inverter to stop.In addition,the inverter is normal but is protected by the overcurrent or overvoltage circuit of the latter stage,so that the output has no voltage.If the 12V main output power output is idling,it will cause over-protection and make the output no voltage.
3,the power supply output voltage is not allowed
Under normal circumstances,the allowable voltage range of the regulated DC voltage of each control system is within±5%of the rated value.If it exceeds this range,the voltage adjustment potentiometer can be adjusted.Adjust the main output voltage file to the standard value.If it is not possible to adjust to the standard value,the potentiometer may be broken or the regulator tube may be broken.
If only a certain voltage deviation is large,it is likely that the rectifier diode is damaged.Try to exchange the same type of diode as much as possible.Sometimes the load capacity of the switching power supply is poor,and the output voltage is also reduced too much.This may cause the circuit operating point to deviate from the linear region due to parameter changes,such as the gain of the amplification section is reduced,and the detection circuit is in a nonlinear state.
4,the switching power supply emits a repeated special noise
This is usually caused by the low operating frequency.The oscilloscope can be used to detect the pulse width modulator,which is about 20 kHz during normal operation.If the capacity of the timing loop capacitor becomes larger,it will also cause the oscillation frequency to be too low,so that the power supply produces a special repeated sound.The switching power supply is not working properly.Replace the appropriate capacitor to restore its normal operation.
The unstable power supply of the industrial power grid or the accidental failure of the system power supply is inevitable.This requires the system to protect the data in the field in the event of a power failure.When the voltage returns to normal,the program can continue to be executed from the power down.To ensure the normal operation of CNC machine tools,to ensure the production of CNC machining parts.