Experience and skills of inverter maintenance (2)

2021-11-03 09:33:24 jact_elec

Experience and skills of inverter maintenance (2)

In the last article, JACT presented the practical experience and operational skills of inverter maintenance. Here are five new inverter repair and maintenance tips to share with you. Reading this article carefully will help you in your work in the field of inverter repair.

1. Rely primarily on the multimeter to detect and use a digital multimeter to do so now. Regarding the maintenance of various frequency converter faults, about 65% of them are solved with a multimeter. As for how to use a multimeter to measure, I think most electrician friends can be proficient in the application. I only emphasize one point: because there are many high-voltage energy storage components inside the inverter, please remember to discharge before performing the measurement operation after the power is off, otherwise the multimeter will not be guaranteed. The appearance and color of the model shown in Figure 4 look the same. The nominal resistance value of the 1 / 4W color ring resistor is 15KΩ, and the value measured with a multimeter has become infinity (due to resistance deterioration,Some inverter manufacturers’22KW inverters will have fault reports of " output current imbalance ").

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2. After talking about using a multimeter to measure, let's talk again about our test, which refers to using an oscilloscope that can visually display the waveform. When it comes to inverter maintenance, oscilloscopes are generally used for the six inverter pulse signals of the inverter (the brake power tube / module trigger signal is a switching value, and no need to use an oscilloscope to detect). When using an oscilloscope to detect, pay attention to whether the signal waveform is normal or not to meet the work requirements; Whether the driving signal amplitude and frequency range meet the driving requirements and other information. This maintenance method is indispensable for the maintenance of the inverter power tube / module after it burns out!

3. The short circuit is used to repair the inverter, especially when the IGBT / IPM is removed due to damage, during the independent ignition inspection and pulse circuit repair, if the pulse photocoupler model is A316J, which contains the fault detection function for IGBT / IPM When using the chip, the optocoupler cannot be powered up normally due to damage or removal of the module. At this time, it is necessary to use wires to short-circuit the components for IGBT / IPM fault detection (mainly high-voltage flyback diode anodes) and the negative end of the inverter DC bus (some labeled N or GND), in order To deceive the main investor control. Let you think that the power module is intact, and then achieve the purpose of the normal transmission of the drive pulse signal. Figure 5 shows a brief introduction to the detection of IGBT modules in a certain brand of 55KW inverter and pulse signal control circuit.
4. Everyone knows that the internal circuit of the inverter contains many protection functions for itself or for the load, when these protection functions have problems, we can use the disconnect / disconnect method to judge and repair.
For example: All inverters have output overcurrent protection and supervision functions. However, some products are very unscientific in the design of this function: when a failure occurs, it is impossible to clearly indicate which phase has a problem, which is very troublesome for the repairman. For the maintenance of this situation, we can take the method of disconnecting the current transformer / current sensing subunit used for each phase detection of the subsequent comparison circuit one by one. When the disconnected channel input signal fault disappears, the point of failure is clear (some models require a manual reset to clear the fault screen). Of course, this method is also suitable for checking protection circuits such as temperature.

AS a Chinese leading inverter manufacturer, JACT provides you with high-quality inverters and inverter related services.

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