Motor inverter maintenance skills: measure, text, short, break, release

- Dec 06, 2019-

1. Measure

This method mainly relies on multimeter detection, and for the time being, digital multimeter is often used.For frequency converter of troubleshooting, use multimeter solving accounted for about 65% of for how to use a multimeter to measure, I believe our electrician friends can skilled utilization, emphasize here: due to the frequency converter internal high-voltage energy storage component, remember first discharge again after power off the line survey work, otherwise multimeter hard ah!

2. Text

Having said that, let's talk about text again -- it means using an oscilloscope that can display the waveform directly.As far as inverter maintenance is concerned, oscilloscopes are generally used for inverter six-channel inverter pulse signal (the driving signal of the brake power tube/module is the switching volume, so there is no need to use oscilloscopes for detection).When using oscilloscope, we should pay attention to whether the waveform of the signal is normal or not.Whether the amplitude and frequency range of the driving signal meet the driving needs, etc.This kind of maintenance method for the inverter power tube/module burned after the overhaul, is indispensable!

3. Short

This method says short catch.During the maintenance of frequency converter, especially when IGBT/IPM is removed due to damage, it is impossible to open the optocoupler normally due to module damage or removal, if the drive optocoupler model A316] contains the chip with fault detection function of IGBT/IPM.In this case, the components for IGBT/IPM fault detection (most of which are high reverse voltage diode anodes) need to be short-circuited with wires to the negative end of the converter's dc bus (sometimes N or GND), so as to trick the main controller of the converter into thinking that the power module is intact and the drive pulse signal can be sent normally.

4. Break

Break -- disconnect.It is well known that the internal circuit of the converter contains many protection functions for itself or load. In case of any problem with these protection functions, we can use the method of circuit breaking/disconnecting to determine the maintenance.Example: all frequency converters have the protection function of over current monitoring.But part of the product will be the function of the design is very unscientific - failure to clearly identify the phase of the problem, which is very frustrating for the maintainer.In view of this kind of maintenance, we can take the current transformer/current detection subunit used in each phase detection one by one and the subsequent comparison circuit to disconnect the practice, in the disconnect all the way the input signal fault disappeared

5. Release

"Release" means to discharge.The inverter contains a variety of electrolytic capacitors of various specifications and capacities, which reduce the probability of inverter failureVery high by comparison.For these capacitors