Nov 24, 2020
The inverter is broken, can I just replace it with a brand of similar specifications and use it?
As long as it is an AC asynchronous motor, the inverter is almost universal, but there are problems with power and voltage specifications. Different brands of motors and different brands of inverters are completely matched, at least there is no difference in light load occasions. There is no problem that the inverter and the motor are not universal, because the inverter is a switching AC power supply that controls the V/F ratio, which is the core reason why the inverter can be widely used.
Pay attention to the inverter and motor wiring
If you use a brand A motor and a brand A inverter, and switch to a brand B inverter to drive a brand A motor, you must first consider the installation problem and whether the size can be installed.
The main circuit wiring, it is estimated that several people will not connect it wrong. After all, the main circuit of the inverter is almost always RST input, UVW output, each inverter is similar, and even if there are individual differences, the instructions will be clearly marked of.
The key is that the control loop may be different, although the function is the same, for example, figure out what wire is connected to the terminal to start, just move the original wire, and the number of terminals for the given frequency of the potentiometer, the two should correspond on. When removing the brand A inverter, you need to make the label of each line, and it should be wrapped with tape to prevent some number tubes from falling off. In principle, the original separate line needs to be wrapped with tape; However, the original short-circuited thread ends need to be bandaged together, and all the control wires cannot be wrapped together. This may cause confusion at critical times, or accidentally send the wrong power and cause serious problems.
When replacing the B brand inverter, you must first study the circuit diagram of the B brand inverter and figure out the corresponding relationship between it and the A brand, and install them one by one. Before turning on the power, it is generally recommended to check more than twice. Make sure there are no errors, and then power on.
If the control circuit is wrong when the inverter is replaced, of course, the new inverter cannot be used to drive the original old motor. Many people misunderstand that the inverter cannot be used with each other. In fact, it is caused by wrong wiring. .
The inverter parameters must be adjusted correctly
If only a single motor and a single inverter work, there is not much connection with other instruments or other inverters. After the inverter is connected to the line, it can generally be started directly, but if it is connected to other things If there is a connection, pay attention to whether some logic input or output terminal functions of the inverter are used for interlocking control. In this way, when a new inverter is replaced, some function values of the interlocking I/O ports used need to be reset. Otherwise, the inverter will not work normally due to incorrect parameters.
Sometimes, when the inverter is replaced with a new inverter, the motor does not work normally, such as lack of strength or slow rotation. It is not ruled out that it is caused by unreasonable settings such as the V/F ratio or the maximum frequency. After all, some inverters have more hardware differences. It needs some compensation on site to improve it.
If it was originally a vector inverter, some torque control needs to be performed. If you replace an inverter without vector function, of course, it cannot meet the requirements. Even if you change to a new vector inverter, you must consider re-matching. Relevant parameters of vector control, otherwise it may cause abnormal torque control, unstable motor speed, weak acceleration, poor control accuracy, etc. Some even directly over-current alarm.
Synchronous permanent magnet motor control, it may not be common between inverters
The permanent magnet synchronous motor can also be controlled by a vector inverter, which is actually a servo control system. The rotor of the permanent magnet synchronous motor generally has magnetic poles. The magnetic poles are divided into north and south. The magnetic poles are in the 360 circle and will be in multiple positions. When the inverter controls it, you need to know the current position and The phase relationship between the stators, so that when the motor starts, the torque is large enough and the speed fluctuation is small. The current position of this magnetic pole is judged by the inverter by the pulse of the encoder.
In theory, if the motor manufacturers all use the same encoder and the motor specifications are the same, the inverter can be the same and universal. However, because the technical content of the servo system is relatively high, and there is no organization in society that requires each manufacturer to comply with what standard to make the data format of these encoders like the unified charger interface. ", these data formats are often not published, so that your own inverter can only be used with your own motor. If you change someone else’s, it just can’t be used. This kind of problem is caused by man. Therefore, if the motor is broken, it is often only possible to buy the same brand and the same specification motor. If it is changed to another brand, it is generally not usable. The same applies to the frequency converter.