Solution to Delta's overload trip fault

1. The main reason for VFD overload

(1) Mechanical overload. The main characteristic of overload is the heating of the motor, which can be detected by reading the operating current on the display.

(2) The three-phase voltage imbalance leads to excessive running current in a certain phase, resulting in overload tripping. It is characterized by uneven heating of the motor, which may not be detected when reading the operating current from the display (because the display only shows one phase of the current).

(3) Problem, part of the current detection inside the VFD, the detected current signal is too large, resulting in tripping.

Solution to Delta's overload trip fault

2.VFD view the method of overloading

(1) Check whether the motor is heated. If the temperature rise of the motor is not high, the first thing should be

Check whether the preset value of the electronic thermal protection function of the VFD is reasonable. If there is a margin in the VFD, the preset value of the electronic thermal protection function should be relaxed.

If the temperature rise of the motor is too high and the overload is normal, it means that the motor is overloaded. In this case, the first thing is whether the transmission ratio can be appropriately increased to reduce the load on the motor shaft. If you can, add the gear ratio. If the gear ratio cannot be added, the capacity of the motor should be added.

(2) Check whether the three-phase voltage on the motor side is balanced. If the three-phase voltage on the motor side is unbalanced, check whether the three-phase voltage at the VFD output is balanced again. If it's also unbalanced, the problem is within the VFD.

If the voltage at the output of the VFD is balanced, the problem is in the line from the VFD to the motor. Check that the screws of all terminals are tightened. If there is a contactor or other electrical appliance between the VFD and the motor, check whether the terminal blocks of the relevant electrical appliances are tightened and whether the contact is good.

If the three-phase voltage on the motor side is balanced, the operating frequency should be known when tripping:

If the operation frequency is low, do not use vector control (or do not use vector control), reduce the U/f ratio first. If the load can still be driven after the drop, it means that the original preset U/f ratio is too high and the excitation current peak is too large. It is possible to drop the current by decreasing the U/f ratio. If there is no static load after the reduction, the capacity of the VFD should be added; If the VFD has a vector control function, it should be vector controlled.

Solution to Delta's overload trip fault

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