The inverter can be divided into single-phase 220V and three-phase 380V(or 400V, 460V), and the input phase loss only exists in three-phase products. The main circuit of inverter, R, s and T are three-phase AC input. When one of the phases is disconnected due to the fault of fuse or circuit breaker, phase failure occurs.
1) the mechanical load is too heavy, its main feature is that the motor is hot, touching the motor shell by hand, which is obviously hot; it can also read the running current from the inverter display screen, compare with the rated current of the motor, and judge the overload situation.
2) Three phase voltage unbalance
The operation current of a certain phase is too large, resulting in overload trip. Its characteristic is that the motor heating is unbalanced, and it may not be found when reading the running current from the display screen (because many inverter displays only one phase current); the effective method is to measure the three-phase output voltage of the inverter with a voltmeter, so as to judge whether the inverter is lack of phase or voltage imbalance.
The internal current detection part of the inverter breaks down, and the detected current signal is too large, resulting in overload trip
INVT GD series supports a wide range of voltage levels. The rated input voltage of the -4 product is 380(-15%)-440(+10%), and the input frequency supports 47-63Hz, which can use our standard products normally.
The over-current caused by motor winding short-circuit, wiring short-circuit and terminal short-circuit is the most dangerous over-current, because the steepness of the current is very easy to cause damage to the IGBT module. The characteristics of this kind of over-current are: the inverter trips when it is running and cannot work. In this case, do not repeat the test, to carefully check whether there is a short circuit fault in the external circuit.
When the normal operation of the inverter often over-current trip, the load instability generally. Whether it is impact load or non impact load, as long as the overcurrent trip, first to check the inverter overcurrent value meets the inverter's tolerance current, if it reaches the limit current, it is necessary to consider the replacement of bigger power inverter.
Because of the inertia of the load's bigger, the speed of the inverter is shorter, which leads to the starting trip; the static friction force of the load is big, and the starting torque is big. The characteristics of the starting over-current trip is: it does not trip at the re-start, but the trip during acceleration. In the starting process, the trip can be solved by setting parameters.
Firstly, confirm that the GD200A input power supply is normal, and observe that the input voltage is normal during operation. If a UV fault is reported during operation for models above 55kW, and it is obvious that the DC bus voltage drops. Then we need to start from the following two aspects:
1. The fan may cause a short circuit, check the fan. Please disconnect the fan, then try to test. You will find there is a cable between fan and auxiliary power board, please take out that cable. Then try to check the problem happen or not. If not happen, that means fan need to replace.
2. Listen to whether there is a sound of contactor closing when starting, if not, replace the contactor and check 24 V power board.
The minimum working voltage of 380V inverter switching power supply is 250V, We usually do not recommend using 220 V power supply to power on the 380V drive, because it will report undervoltage fault and can not run. Therefore, it is necessary to reduce the under voltage protection point in group P29, turn off the power failure and frequency reduction, and adjust the voltage points of over-voltage stall and energy consumption braking. VF control may not be a problem, if vector control is used, the performance may be reduced; the input and output current should not exceed the current marked by the original inverter.That is to say, the power should be reduced, need to derate the drive. If it is necessary to use this way in an emergency, please contact the INVT technical engineer.
In the process of deceleration or stop of the inverter, due to the set deceleration time is too short or the braking capacity is not enough, the bus voltage inside the inverter is increased and protection (also known as overvoltage stall) occurs. As a result, the inverter loses the speed control of the motor. At this time, a long deceleration time should be set to keep the bus voltage in the transformer from rising too high to realize normal deceleration control. In the process of increasing speed of inverter, the set acceleration time is too short or the load is too heavy, and the grid voltage is too low, which leads to the converter over-current and protection (also known as over-current stall). When the inverter loses the speed control of the motor, a longer speed up time should be set to maintain no over-current and realize normal speed-up control.