1、Protection function of inverter?

(1) Automatic corrective action after detecting abnormal state, such as over-current stall prevention and regenerative over-voltage stall prevention.

(2) Block the PWM control signal of power semiconductor device after detecting abnormality, so that the motor stops automatically. Such as overcurrent cutoff, regenerative overvoltage cutoff, semiconductor cooling fan overheating and transient power failure protection.

2、Why does the protection function of the inverter operate when the load is continuously connected with the clutch?

When connecting a load with a clutch, at the moment of connection, the motor changes sharply from the no-load state to the area with a large turndown rate, and the large current flowing through causes the inverter to trip over current and cannot operate.

3、In the same plant large motors move together and the inverter stops during operation, why is this?

When the motor starts, the starting current corresponding to the capacity will flow, and the transformer on the stator side of the motor will produce a voltage drop, and this voltage drop will have a big impact when the motor has a large capacity, so the inverter connected to the same transformer will make a judgment of undervoltage or transient stop, so sometimes the protection function (IPE) will act and cause the operation to stop.

4、What is the meaning of the stall prevention function?

If the given acceleration time is too short, the output frequency change of the inverter far exceeds the speed (electric angle frequency) change, the inverter will trip due to over-current flow and the operation will stop, which is called stall. In order to prevent stall so that the motor continues to run, we must detect the size of the current for frequency control. When the acceleration current is too large, the acceleration rate is slowed down appropriately. The same is true when decelerating. The combination of the two is the stall function.

5、Is there any restriction on the installation direction when installing the inverter?

The structure of the internal and back of the inverter considers the cooling effect, and the relationship between the top and bottom is also important for ventilation. Therefore, for the unit type in the tray, hanging on the wall are taken longitudinal bit, as far as possible vertical installation.

6、Inverter over-voltage

Overvoltage alarm is usually present at the time of shutdown, the main reason is that the deceleration time is too short or braking resistors and braking units have problems.

7, inverter temperature is too high

In addition, the inverter also has a temperature too high fault, such as the occurrence of high temperature alarm, after checking the temperature sensor is normal, it may be caused by interference, the fault can be shielded, in addition to check the fan and ventilation of the inverter. For other types of faults, it is best to contact the manufacturer to obtain a quick and feasible solution.

8、Overcurrent is the most frequent phenomenon of inverter alarm

(1) When restarting, it trips as soon as the speed is increased. This is a very serious phenomenon of overcurrent. The main reasons are: load short circuit, mechanical parts have jammed, inverter module damage, motor torque is too small, etc.

(2) Power on the trip, this phenomenon generally can not be reset, the main reasons are: bad module, bad drive circuit, bad current detection circuit. It does not trip immediately when restarting but when accelerating. The main reasons are: the acceleration time setting is too short, the current upper limit setting is too small, and the torque compensation (V/F) setting is high.

9、Is it possible to put the motor directly into a fixed frequency inverter without using soft start?

Yes, it is possible at very low frequency, but if the given frequency is high, it is similar to the condition of direct starting from the industrial frequency power supply. Will flow too large starting current (6 ~ 7 times the rated current), due to the inverter cut off the overcurrent, the motor can not start.

10, the motor over 60Hz operation should pay attention to what issues?

(1) machinery and devices operating at that speed to be fully possible (mechanical strength, noise, vibration, etc.).

(2) the motor into the range of constant power output, its output torque to be able to maintain the work (fans, pumps and other shaft output power in proportion to the cube of the speed increases, so the speed of a little increase should also be noted).

(3) produce bearing life problems, to be fully considered.