The modulator maintenance, the maintenance crew reference, must read
One across
Overflow is the most frequent phenomenon in which transvestites alert。
1. 1 phenomena
(1) when restarting, jumps at one litre. This is a very serious phenomenon. The main reasons are: load short circuits, which are stuck in mechanical parts; reversible module damage; and the low rectangularity of electric motors。
(2) electricity jumps, a phenomenon that is generally not re-established, mainly because of: bad modules, bad driving circuits, bad current detection circuits。
(3) when restarting, it does not jump immediately, but accelerates mainly because the acceleration time is too short, the current cap is too small and the rectangular compensation (v/f) is set at a high level。
1. 2 examples
(1) one lg-is3-4 3. 7kw frequency converter jumps "oc" as soon as it starts
Analysis and maintenance: the opening of the hood did not reveal any signs of burning, the online measurement of the igbt (7 mbr25nf-120) basic judgement was not in question, and the large power transistors that were removed from the igbt to measure the seven units were well opened and shut down for further diagnosis. When measuring the first half of the bridge's driving circuits, there was a clear difference between the road and the other two. A3120 the output foot is the same as the negative short circuit of the power source, and the latter three paths are basically replaced. The module is equipped with electricity and is running well。
(2) a beltro-vert 2. 2kw variable frequency electronization jumps “oc” and cannot be restored。
Analysis and maintenance: no problems were identified from the reverse module first. A second inspection of the driving circuits is also not unusual, and it is estimated that the problem is not in this section and that it may come out of the excess signal processing area, and when the circuit sensors are removed, they are powered up, indicating that everything is normal, so it is assumed that the sensors are broken and that a new product is replaced with a load experiment。
