Goodrive300-01 inverter for air compressor Common EMC problems and remedies
-92-
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 with 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.
B.3 Unable to stop or indicator shimmering 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
d)
Indicating buzzer
Solution:
Check and confirm the abnormal signal cable is routed with motor cable motor cable at a
distance of at least 20cm;
Parallelly connect the digital input terminal (S) used for start/stop control with other idle digital
input terminals. For instance, S1 terminal is used for start/stop control, S4 terminal is idled, then
try to short circuit S1 terminal with S4 terminal.
B.4 Leakage current and residual current device (RCD)
As the inverter outputs high frequency PWM voltage to drive the motor, the distributed capacitance
against radiator from internal IGBT and between rotor and stator of the motor may cause the inverter
to generate high frequency leakage current against the ground. While the RCD is used to detect the
power frequency leakage current when grounding fault occurred to electrical circuit, the application of
inverter may cause mal-operation of RCD.
