1. Acceleration time is too short
Theoretically, the longer the acceleration time, the stronger the ability to lift with load. If the acceleration time is set too short, some inverters will display overcurrent or overload overheating alarms, etc., but some will not display it and will just get stuck. A certain frequency range cannot be reached.
2. V/F ratio is too large
This is also called torque ti in some frequency converters. If this parameter is set too large, sometimes it will not start normally. Reducing it appropriately will solve the problem.
3. Vector control parameters do not match
In the vector control mode, the internal resistance, inductance and other parameters of the motor need to be accurately measured and matched well with the vector parameters of the inverter. After running for a period of time, the motor parameters will overheat and cause offset. At this time, the current will be too large and the inverter will not be able to operate. If you start the motor normally, the frequency may get stuck at a certain segment point. Re-optimizing the parameters can solve the problem.
4. The high frequency and maximum frequency settings are too low.
Generally, these two parameters are set to a large value, but unless some careless electricians change these two parameters, it will also cause the frequency to be unable to be increased.
5. Some special occasions require matching of parameters.
In some cases, the low frequency cannot be set too low. For example, in a constant pressure water supply system, after the low frequency is set to 0Hz, when the water pump pressure is low and exceeds the starting frequency of the inverter, the inverter starts to accelerate, and the pressure never increases. The inverter The frequency could not be increased to 50Hz, only about 38Hz. I repeatedly set and adjusted the PID, but the frequency could not be increased. Only when the low frequency of the frequency converter is set to about 15-20HZ can the acceleration of the frequency converter be satisfied and the water pump can be kept at a constant pressure to a certain pressure position. Although the pressure meets the constant pressure requirements, when no water is used, the frequency converter cannot stop completely and always maintains a low frequency speed.
This is because: in a constant pressure water supply system, the low frequency of the frequency converter cannot be set to 0HZ. It is generally at least about 20HZ, which is determined by the flow rate and head of the water pump.
The solution is to set the sleep frequency. When the water pump runs at the frequency when it is not using water (for example, 28HZ) for a few minutes, the water pump sleeps. When the pressure drops to 0.2-0.4MP lower than the set pressure, the water pump starts. Another method is to set up a timed water supply, which is divided into several time periods. Generally, constant pressure water supply controllers have the functions mentioned above.
6. Hardware problems
After the transformer of the frequency converter has a problem, the correct current cannot be measured normally, and a similar situation may also occur. In addition, a certain measuring component on the motherboard has aged. This situation often occurs when repairing the frequency converter. bump into.