Stop Failure And Indicator Shimmering Due To Motor Cable Coupling - Kruger Ecowatt K320 Series Operation Manual

Ecowatt Drive K320 series
®
use a multimeter to measure and ensure that the resistance between the ground block and
PE terminal is lower than 1.5 Ω).
2. Do not connect the VFD and motor to the same ground terminal as the upper computer. It
is recommended that you connect the VFD and motor to the power ground, and connect
the upper computer separately to a ground stud.
3. Try to short the signal reference ground terminal (GND) of the VFD with that of the upper
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).
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.

7.7.3 Stop failure and indicator shimmering due to motor cable coupling

Interference phenomenon
1. Stop failure
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 applicable.
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Troubleshooting