Allen-Bradley PowerFlex753 drive Maintenance method

PowerFlex753 AC drive is the most widely used Allen-Bradley series on the market,Let's take this series of models 20F11RC3P5JA0NNNNN as an example to introduce the general maintenance methods:

1. Backup board replacement inspection method
It is a very effective method to use a spare circuit board or a circuit board of the same type to confirm the fault and narrow the scope of inspection. If there is a problem with the control board, there is often no other way but to replace it, because most users will hardly get the schematic diagram and layout diagram, so it is difficult to do chip-level maintenance. Circuit boards other than the control board such as the power supply board and the driver board can be repaired.

2. Quarantine inspection method
Some faults are often difficult to judge in which area, and the method of isolation can simplify complex problems and find out the cause of the fault quickly.

3. Visual inspection method
It is to use the sensory organs of human hands, eyes, ears and nose to find the cause of the failure. This method is commonly used and used first. The maintenance principle of "first outside, then inside" requires maintenance personnel to use the methods of looking, smelling, asking, and touching when encountering a fault, and check one by one from the outside to the inside. Some faults can be quickly found by using this intuitive method, otherwise it will waste a lot of time, or even have no way to start.
Use vision to check whether the connection of line components is loose, whether the disconnected contactor is ablated by electric shock, whether the pressure is constant, whether the heating element is overheated and discolored, whether the electrolytic capacitor is expanded and deformed, and whether the voltage-resistant component has an obvious breakdown point. After power on, smell whether there is a burnt smell, and touch the heating element to see if it is hot. It is very important to also ask, asking the user about the process of the failure will help analyze the cause of the problem and facilitate the direct hit. Sometimes asking colleagues is also a shortcut.

4. Temperature rise and fall inspection method
This method is very effective for some special failures. Artificially heating or cooling some components with poor temperature characteristics to generate "diseases" or eliminate "diseases" to find the cause of the failure.

5. Destruction inspection method
It is to take some means to cancel the internal protection measures and simulate the fault condition to destroy the problematic device. Highlight faulty devices or areas. First of all, it is stated that this method must be very sure to control the development of the situation, that is, the maintainer must understand the state of the most serious damage, whether the most serious further damage can be accepted, and have control methods to avoid more serious damage. destroy.

6. Tap inspection method
The frequency converter is composed of various circuit boards and module connectors. Each circuit board has many solder joints. Any weak soldering or poor contact will cause failure. Hit the suspected bad part with an insulating rubber stick. If the fault of the inverter disappears or reappears, it is likely that the problem lies there.

7. Scrub inspection method
Many special faults appear and disappear from time to time, making it impossible to judge and deal with them. At this time, you can clean the circuit board with water or alcohol, and at the same time use a soft brush to remove dust and rust on the circuit board, especially pay attention to the places where the solder joints are dense, the via holes and the circuit close to the 0V copper layer should also be cleaned , then blow dry with hot air. Often achieve unexpected results. At least it helps the application of observation method.