Goodrive350-19 series VFD Troubleshooting
- 411 -
computer controller to ensure that ground potential of the communication chip on the control
board of the VFD is consistent with that of the communication chip of the upper computer.
4. Try to short GND of the VFD to its ground terminal (PE).
5. Try to add a safety capacitor of 0.1
μF on the power terminal of the upper computer (PLC, HMI,
and touch screen). During this process, pay attention to the voltage of the power supply and the
voltage endurance capability of the capacitor. Alternatively, you can use a magnet ring (Fe-based
nanocrystalline magnet rings are recommended). Put the power L/N line or +/- line of the upper
computer through the magnet ring in the same direction and wind 8 coils around the magnet ring.
8.7.3 Failure to stop and indicator shimmering due to motor cable coupling
Interference phenomenon
1. Failure to stop
In a VFD system where an S terminal is used to control the start and stop, the motor cable and control
cable are arranged in the same cable tray. After the system is started properly, the S terminal cannot
be used to stop the VFD.
2. Indicator shimmering
After a VFD is started, the relay indicator, power distribution box indicator, PLC indicator, and
indication buzzer shimmers, blinks, or emits unusual sounds unexpectedly.
Solution
1. Check and ensure that the exception signal cable is arranged 20 cm or farther away from the
motor cable.
2. Add a safety capacitor of 0.1
μF between the digital input terminal (S) and the COM terminal.
3. Connect the digital input terminal (S) that controls the start and stop to other idle digital input
terminals in parallel. For example, if S1 is used to control the start and stop and S4 is idle, you
can try to connect S1 to S4 in parallel.
Note:
If the controller (such as PLC) in the system controls more than 5 VFDs at the same time
through digital input terminals (S), this scheme is not available.
8.7.4 Leakage current and interference on RCD
VFDs output high-frequency PWM voltage to drive motors. In this process, the distributed
capacitance between the internal IGBT of a VFD and the heat sink and that between the stator and
rotor of a motor may inevitably cause the VFD to generate high-frequency leakage current to the
ground. A residual current operated protective device (RCD) is used to detect the power-frequency
leakage current when a grounding fault occurs on a circuit. The application of a VFD may cause
misoperation of a RCD.
1. Rules for selecting RCDs
(1)
VFD systems are special. In these systems, it is required that the rated residual current of