How to avoid frequency converter soft failure

2017-07-24 focus number:

There are many soft faults in frequency converters, which is one of the common faults in the operation of frequency converters. So how can we reduce the frequency converter soft failure? This is all inverter manufacturers and users are very concerned about the problem. The details are described below.

  

The methods to reduce the soft fault of the frequency converter are as follows: 1. 2. Overcurrent detection is the most frequent phenomenon of frequency conversion alarm.

  

In general, overvoltage alarm usually occurs when the stop, the main reason is that the deceleration time is too short or brake resistance and brake unit has problems. Undervoltage is also a problem we often encounter in use. Mainly because of main loop is too low voltage (220 v series is lower than 200 v, 380 v series is lower than 400 v), the main reason: a rectifier bridge damage or silicon controlled all the way with work of three way in normal are likely to cause under-voltage fault, the second main circuit contactor is damaged, leading to loss of dc bus voltage on charge resistance may cause undervoltage. There is a voltage detection circuit fault and the occurrence of undervoltage problem.

  

The overcurrent phenomenon is mainly manifested as follows:

(1) When it is restarted, it will trip at one liter of speed. This is a very serious phenomenon of overcurrent. The main reasons are: load short circuit, mechanical parts are stuck; Inverter module is damaged; The torque of motor is too small and so on.

(2) Power on the jump, this phenomenon is generally unable to reset, the main reasons are: bad module, bad drive circuit, bad current detection circuit.

(3) When it is restarted, it does not trip immediately but accelerates. The main reasons are as follows: the acceleration time is set too short, the upper limit of current is set too small, and the torque compensation (V/F) is set too high.


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