AC310 Universal AC Drive Service Manual
1. Circuit description: in the OC detection circuit, OC threshold for the rated current 2.7
times, in the circuit used in the comparator U7, U8, U9, the comparator provides the
reference voltage REF-H, REF-L, the collection of the current IU, IV, IW into the resistor
has a voltage, compared with the reference voltage, when between the two benchmarks, will
not report a fault, beyond the benchmark will report fault OC.
2. Fault type: OC1, OC2, OC3, OC4.
3. The detection method the first test resistor, capacitor, normal in the circuit is often
damaged devices may be comparator U7, U8, U9, in the case of inaccuracy of the reference
voltage REF-H, REF-L will also report a fault OC (reference voltage inaccuracy, according
to the previous voltage point test maintenance methods), but also need to test R107 there is
a foot whether the 3.3V voltage.
4. IC pin voltage
Note: In the measurement of IC pin voltage, are GND measurement, it is best to use an
oscilloscope to measure (multimeter will be less accurate, with a multimeter in measuring
voltage, easy to touch other pins), such as a voltmeter to measure, there will be different.
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