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In general, when you get a faulty inverter, first use a multimeter to check whether the rectifier bridge and the IGBT module have burned, and whether the circuit board has obvious burn marks.
The specific method is: Use a multimeter (preferably analog meter) resistance 1K file, black meter bar connected to the inverter DC terminal (-) pole, with a red stick to measure the three-phase input and three-phase inverter output The resistance of the end, its resistance value should be between 5K-10K, the three-phase resistance value should be the same, the resistance of the output end is slightly smaller than the input end, and there is no charging and discharging phenomenon. Then, in turn, the red bar is connected to the DC (+) pole of the inverter, and the black bar measures the resistance of the three-phase input and the three-phase output of the inverter respectively. The resistance value should be between 5K and 10K. The resistance value should be the same, the resistance of the output end is slightly smaller than the input end, and there is no charge and discharge phenomenon. Otherwise, the module is damaged. At this time, you should not blindly power on, especially if the rectifier bridge is damaged or there are obvious burn marks on the circuit board. In particular, it is forbidden to power on, so as to avoid causing greater losses.
If the above measurement results show that the module is basically no problem, you can observe the power on.
(1) After the power is turned on, the panel displays [F231] or [F002] (MM3 inverter). There are two possibilities for this type of fault. The common problem is that there are problems with the power driver board, and a small part is caused by the main control board. You can try a master control board first, otherwise the problem is definitely in the power driver board section.
(2) There is no display (MM4 inverter) on the panel after power on. The indicator under the panel is [green not blinking, yellow light blinking fast]. This phenomenon indicates that the rectifier and switching power supply are working normally. The problem is in the switching power supply. All the way abnormal (rectifier diode breakdown or open circuit, you can use a multimeter to measure the switching power supply of several rectifier diodes, it is easy to find the problem. For a corresponding rectifier diode problem is solved. This problem is generally the diode voltage is low , caused by a pulsating power supply.
(3) Sometimes [F0022, F0001, A0501] is indefinite (MM4). When tapping the case or moving a panel and the main board, it can be normal. Generally, it belongs to the problem of the connector. Check the connectors of each part. It is also found that individual machines are caused by poor quality of the RC components on the circuit board or poor soldering.
(4) Display [-----] (MM4) after power-on, which is generally a master control board problem. In most cases, the problem of replacing a main control board is solved. Generally, the strong damage from the peripheral control circuit causes damage to some components of the main control board (such as the chip capacitor, resistor, etc.). I analyze and control the heat dissipation of the main control board. Bad and there is a certain relationship. However, there are individual problems on the power board.
For example: a MM440-200kW frequency converter driven by a cement plant in Chongqing, due to a large load inertia, a large starting torque, the frequency of the equipment can only rise up to 5Hz, it will never go up, and the alarm [ F0001]. The customer asked for on-site service. At that time, I considered that: as the inverter itself is not a problem, the problem is that the customer's parameters are not properly set, vector control is used, and the parameters/model of the motor can be correctly set to solve the problem. After another two days, the customer calls me that the inverter has been broken, and the fault phenomenon is the power display [-----]. After on-site inspection and analysis, this kind of failure was caused by the problem of the main control board, because the user did not strictly follow the EMC regulations in the installation process, and the strong and weak power did not separate wiring, bad grounding, and did not use shielded wires, resulting in the main control board. The I/O port was burned. Later, I applied for maintenance service. The SFAE engineers went to the site for maintenance. The replacement of a master control board solved the problem.
(5) Normal display after power-on, and over-current is displayed during a run. [F0001] (MM4) [F002] (MM3) Even if the load is the same, this phenomenon usually indicates that the IGBT module is damaged or there is a problem with the driver board. The IGBT module must be replaced and the driver section must be carefully checked before the power supply can be re-powered. Otherwise, it may be because The driver board problem caused the IGBT module to be damaged again! This problem usually occurs because the inverter is overloaded several times or the power supply voltage fluctuates greatly (especially if it is too low). This causes the pulsating current of the inverter to be too large for the main control board CPU to reflect and take protective measures.
There are some special faults (uncommon but there are some general meanings that can be inferred from each other, and hope to achieve the effect of embarking on an elaboration). For example:
(6) There is a frequency converter (MM3-30KW), which is often stopped for "no reason" during use. It may be normal to start up again. After the machine got me here, I did not find the problem at the beginning. After a long period of observation, it was found that the main contactor did not pick up properly after power-up - sometimes it lost power and jumped. Check the cause of the fault. The result was found to be caused by the low voltage of the filter capacitor leaking from the switching power supply to the contactor's line pack. If the supply voltage is too high, then the problem is not significant. If the supply voltage is low, it will cause contact. Inadvertent shutdown due to abnormal suction.
(7) There is also a frequency converter (MM4-22KW). The power-on display is normal and a [P----] or [-----] appears on the operation signal. After careful observation, it is found that there are some fan speeds. If it is not normal, the fan will be disconnected and [F0030] will be displayed. In the course of maintenance, the alarm may be disordered, and [F0021\F0001\A0501] may appear. When I first give the running signal and then connect the fan, [P ---- ] does not appear, but when a fan is connected, the fan speed is normal, the output three phases are normal, and the second fan is again The speed of the fan is obviously not normal when connected. So I analyzed the problem on the power board. The result is a leakage of the power supply filter capacitor out of the switching power supply, which is solved by replacing the same capacitor problem.
(8) There is a 75kW MM440 inverter in a steel plant. After installation, the MM440 inverter is running normally. After more than half an hour, the motor is stopped. However, the running signal of the inverter is not lost but it is still being maintained. Panel display [A0922 ] Alarm message (inverter has no load), no voltage output of the three-phase output terminal of the measuring inverter. The inverter is stopped manually and the operation resumes normal again. The normal output current of the panel display is 40A-60A. After more than twenty minutes, the same fault phenomenon appeared. At this time, the output current displayed by the panel was only about 0.6A. After analyzing and judging that there is a problem in the current detection unit on the driver board, the problem is solved after replacing the driver board.
Summarizing the above, the proportion of large original devices such as IGBT power modules is not much problem, as I said in the characteristics of Siemens general-purpose inverters, because of the proportion of failure caused by some low-end simple original device problems and assembly problems. More often, if there are drawings and parts, these problems are not difficult to solve and the cost is not high, otherwise it is not easy to solve these problems. The easiest way is to replace the whole circuit board!
3 Conclusion:
The design level of Siemens frequency converter is compared with each brand frequency converter, function is powerful, impeccable! If the design can be considered from the convenience of the future maintenance and improve the quality of parts in the production of the material is the most ideal.
The withstand voltage of the Siemens inverter rectification unit is 1200V. If you can use a 1600V voltage rectifier unit, I think it will greatly improve the stability and reduce the failure rate.
Anti-interference measures need to be strengthened. Siemens inverters sometimes burn the main control board or I/O ports due to interference problems. In my technical support and maintenance process, I felt that only by constantly learning and enriching my business skills, theories guiding practice, and practice being further promoted as a theory, summing up experience in an indefinite and repeated manner can enable my various aspects of knowledge to be continuously strengthened. Keep pace with the rapid progress of science and technology.
Inverter fault analysis
Common fault phenomenon analysis and processing methods: