Beiterui grinding machine inverter repair case
Customer: Shenzhen beiterui
Equipment name: grinding machine
Model: VFD-B delta inverter
Cause of failure: boot without display.
Fault analysis: according to the description of fault phenomena of the user, the actual delivery of the observation, that the customer‘s fault description is true, that the initial diagnosis of inverter switching power supply fault, using the oscilloscope carefully check the output waveform of switching power supply UC3842 is normal, check the current limiting resistor on the current waveform, found that compared with the normal situation is slightly larger, the switching power supply is normal the working current of this type in general about 0.3A (peak to peak), but this inverter has reached more than 0.5A, a preliminary judge for the switching power supply level after a short circuit caused by the static measurement, drive circuit, control circuit board, detection of normal short-circuit, then oexamine switching power supply circuit diagram, found in the switching power supply current detection terminal UC3842, the 3 foot is connected with another way to protect, the chip power supply regulator D2 feet after receiving 3 feet, this should be part of the line switch Over voltage protection. Static test voltage stabilizing tube good characteristics, regulated power supply with power measurement is normal, voltage value at around 21V (voltage 17V), the regulator to remove the machine power supply, the measured current waveform actually returned to normal 0.3A. The detection is the problem caused by the poor performance of the output voltage regulator tube. Re install a 21V regulator tube, the boot test run normally. Fix after all the normal operation of the test.
Common fault repair grinding machine VFD-M: no display, lack of phase, overcurrent, overvoltage, undervoltage, overheating, overload, grounding, parameter error, output module, display no damage, error; Hong Jia Wei complete accessories, professional maintenance engineers, test with the load test to ensure the quality of maintenance.
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