Simple Troubleshooting for VFD - IGBT、Rectifier bridge

Warning:

Before measurement, it is necessary to ensure that the VFD is powered off and the power lines R, S, T and output lines U, V, W are removed. Only after measuring P+/N- and there is no DC voltage can the operation be carried out!

Measure the rectifier module of the VFD:

First, set the multimeter to the "diode" position, and then use the red and black test leads of the multimeter to follow the steps below for detection:

Second, touch the positive terminal P(+) of the DC bus with the black test lead, and touch R, S, and T in sequence with the red test lead. Record the displayed values on the multimeter.

Thirdly, then touch the red test lead to the negative terminal N(-) of the DC bus, and touch the black test lead to R, S, and T in sequence, and record the display value of the multimeter.

Fourth, if the displayed values of the sixth measurement are basically balanced, it indicates that there is no problem with the rectification of the VFD. Otherwise, the rectification module at the corresponding position is damaged.

Measure the IGBT module of the VFD:

First, set the multimeter to the "diode" position, and then use the red and black test leads of the multimeter to follow the steps below for detection:

Second, touch the positive terminal P(+) of the DC bus with the black test lead, and touch U, V, and W in sequence with the red test lead. Record the displayed values on the multimeter.

Thirdly, then touch the red test lead to the negative terminal N(-) of the DC bus, and touch the black test lead to U, V, and W in sequence, and record the display value of the multimeter.

Fourth, if the displayed values of the sixth measurement are basically balanced, it indicates that there is no problem with the IGBT inverter of the VFD. Otherwise, the IGBT inverter at the corresponding position is damaged.