Generally, it is caused by improper cooperation between the brake and the VFD. The frequency of the VFD has increased, but the brake is opened slowly, resulting in excessive current. This problem is particularly easy to occur in the site where the brake is not controlled by the VFD. The best solution is that the brake is controlled by the VFD.
The main reason is that when the motor is in the power generation state, the motor feeds back energy to the inverter to raise the DC bus voltage to the limit value. It is necessary to check whether the braking resistance or braking unit is damaged or works normally.
Increase the closing delay time of the brake to ensure the continuous output of the VFD during the closing action of the brake.
The motor is weak during operation, and the motor shaft can be easily blocked and stopped.
The multi-point VF function is used to improve the output voltage, increase the output torque and solve problems. For example, the frequency and voltage settings are as follows: 40Hz, 15%; 200Hz，58%； 320Hz，88%
Recently a customer noticed that the inverter was spinning in the opposite direction (than adjusted) after a start command was given. The customer has not made any changes to the inverter configuration, no additional disturbances have occurred.
After restarting the inverter works for 1-2 hours correctly, then the error repeats. Interestingly, several other inverters configured identically, work fine. Application: conveyor belt.
In some cases, if the running direction had been changed, perhaps the load is too heavy, inverter be dragged backwards, this is the possible reason.We know that you have several inverters in same application with same motors, but please be informed that the load is different from different goods or quantity on the belt, so that means maybe you think the application are same, the ability of inverter is same, but the load is different. We suggest that please check the load, to see whether that problem one's load is bigger than other sites in some time. And please use vector control mode, set inverter to "P00.13 Forbid to run in reverse direction".
Switching the multimeter to Diode position and test as follows:
1. Set the multimeter to Diode position, connect the black hand with "+", then connect the red hand with R、S、T、U、V、W in order, if all the values is between 0.3--0.5V, both the rectifier and IGBT upper bridge are good.
2. Contrary, connect the red hand with "--", then connect the black hand with R、S、T、U、V、W in order, if all the values is between 0.3--0.5V, both the rectifier and IGBT lower bridge are good.
If the test values is highly unbalance, the rectifier or the IGBT must be broken. And you can't power on in this situation.
More details, please see the attached file.
Notice: Please make sure that the inverter no power, so we call it static test.
Yes, but the battery only supports up to 1C discharge, that is, the discharge power will not be bigger than the battery power. If the battery power is less than the power of the machine, the machine excess power will be wasted.
Thyristor switching module can achieve seamless switching, switching time is less than 10ms; Contactor switching module time is longer, there may be adhesion in the switching process. From 2020, the switching modules of PCs products will be upgraded to thyristor switching modules.
PCS above 500kW are not equipped with transformers, because in most cases, the power grid will have high-voltage transformers.
Under 500kW, compared with the equipment without power frequency isolation transformer, THDu and THDi are smaller, output characteristics are stable, load adaptability is stronger, and power quality is higher, which is more suitable for industrial applications.
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