AC310 Universal AC Drive Service Manual
important, wave-by-wave current limiting can effectively prevent overcurrent, whether
it is a short-circuit or a sudden change in the current of the load suddenly added, when
the current reaches the wave-by-wave current limiting point, blocking the drive signal,
so as to shut down the drive to realize the overcurrent protection of the IGBT, so as to
ensure that the IGBT will not be damaged by overcurrent. To make the wave-by-wave
current limiting function normal, the corresponding control signals must be normal, so
that there is a corresponding wave-by-wave current limiting comparison circuit on the
control board, when the current exceeds the wave-by-wave current limiting point, the
CPU sends out a command to limit the current, and the wave-by-wave current limiting
threshold set by our company is 2 times of the rated current.
2. Fault type: Wave-by-wave current limiting function will not be entered.
3. Detection method: Test the corresponding SMD double diode, replace the comparator
U7, U8, U9 if the resistor and capacitor are normal, if the above fault occurs, it is not
only a problem of the circuit, but also a problem of the circuit before generating IU-C,
IV-C, IW-C signals.
4. IC Pin Voltage
Note: In the measurement of IC pin voltage, are on the GND measurement, it is best to
use an oscilloscope to measure (multimeter will be less accurate, with a multimeter in
the measurement of voltage, easy to touch the other pins), such as a voltmeter to
measure, there will be different.
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