1. Power on the display is normal. Start the operation, that is, jump "GF" fault, did not run up, or there is no sign of a little operation. It's a joy to jump to earth fault. The "GF" fault at this time is equivalent to the "OC" fault of other inverters, and the fault location is in the inverter module or drive circuit. At the moment when the CPU sends the trigger pulse, it detects that there is an abnormally large tube pressure drop in an IGBT tube, and fails to open normally during the arrival of the trigger pulse. In fact, during this time, the current transformer of the frequency converter does not detect the signal of the output current at all. The "GF" fault signal at this time is the module fault detection circuit of the drive circuit, which feeds back to the CPU. (This fault action is derived from the test.)
Repair and inspection: Check the quality of the inverter block, in particular, can not ignore the trigger terminal check; check the drive circuit, in particular, can not ignore the drive power filter capacitor check, measure the normal drive voltage, but whether there is a certain current drive capability.
2. The "GF" fault in the running jump is the fault reported by the current detection circuit. Two aspects must be distinguished. On the one hand, it is a normal fault shutdown action. An abnormal overcurrent is detected by the current transformer, and the CPU is used to implement the shutdown protection. On the other hand, the subsequent current signal processing circuit of the current transformer is defective, such as a resistance element. The variable value causes the “GF†fault voltage setpoint to drift, causing false alarms. The signal from the current transformer is processed all the way through the operational amplifier and sent to the CPU for current display and fault alarm processing. The voltage comparator is sent all the way to the “GF†fault. (Note: The follow-up circuit of this current transformer has not been investigated in detail, but it is inferred from numerous fault phenomena and is for reference only.)
Repair and inspection: When the implementation is indeed a false alarm, it does not necessarily have to be repaired. Check the current transformer and its follow-up circuit for repair.
3. Incidentally, when the overcurrent fault of OL1, OL2, and OL3 is reported during operation, the current signal is detected by the current transformer and the subsequent current signal processing circuit, and the current signal is sent to the CPU after judgment and down-clock processing. After the overcurrent fault signal was reported. For a sudden abnormal over-current fault, or module damage, abnormal drive circuit fault, the CPU is directly fed back by the drive circuit, and the CPU will report an OC fault.