Unstoppable Or Shimmering Indicator Caused By Coupling Of Motor Cable - INVT Goodrive300-21 Series Operation Manual

Goodrive300-21 series dual inverter integrated machine for air compressor

Check if the ends of A, B cable of the 485 communication bus are connected reversely.

Check if the communication protocol (eg baud rate, data bit check, etc)of the inverter is in
consistent with that of the upper PC;
If it is confirmed that the abnormality is caused by interference, rule out the problem cause by below
means:

The communication cable cannot be routed with motor cable in the same cable tray;

In multi-machine application, the connection of inverter communication cables should adopt
chrysanthemum mode to improve anti-interference ability;

In multi-machine application, it is necessary to confirm that the drive capacity of the master is
strong enough;
For multi-machine connection, both ends should be connected with 120Ω terminal resistors.

Solution:

Check and confirm the motor ground line is connected to PE terminal of the inverter (if motor
ground line has been connected to the grounding bar of inverter cabinet, measure with
multimeter to confirm that the resistance between grounding bar and PE terminal is less than
1.5Ω);

Inverter and motor cannot be common grounded with upper PC of communication (PLC, HMI,
touch screen, etc). It is recommended to connect the inverter and motor with power GND while
the upper PC of communication should be connected to the ground pile separately;

Try to short circuit reference GND of inverter signal with the reference GND of upper PC
controller signal to ensure the ground potential of their communication chips is the same;

Try to short circuit reference GND of inverter signal with grounding terminal (PE) of the inverter.
D.3. Unstoppable or shimmering indicator caused by coupling of
motor cable
Interference phenomena:

Unable to stop
For inverter system whose start/stop is controlled by S terminal, the motor cable and control cable are
routed in the same cable tray. After system starts, it cannot stop via S terminal.

Shimmering indicator
After inverter starts to run, shimmering, flickering or abnormal noise occurred to below devices:
a) Relay indicator
b) Indicator of distribution box
c) PLC indicator
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96
Appendix D