Interference Processing - INVT Goodrive3000 Series Operation Manual

Goodrive3000 series medium voltage VFD EMC installation guidelines
B.2 Interference processing
There are mainly two interferences, electromagnetic noise interference and harmonic interference, which
may cause interference to nearby electronic and electric devices by conduction, radiation and near-field
induction, etc. and thus the devices malfunction. For different cases of interferences, you can refer to the
following solutions:
B.2.1 Electromagnetic noise interference
Generally, conduction interference transmits interference via cables. When the interfered devices and the
VFD use the same power or electrical connection, conduction interference may easily occur. For such
interference, you can adopt the following solutions: install the high-performance power filter of our
company at the power input side of the VFD; install the amorphous magnetic ring on the output motor
cable and coil 2–3 turns, in the case of severe conditions, you can install the output power filter; install
small amorphous magnetic ring on the signal cable and coil 2–3 turns; reduce the carrier frequency
appropriately. (Cautions: Too low carrier frequency will increase harmonic and motor noise.)
Radiation interference transmits interference via space and the interfered devices are generally
instruments with weak signals, such as sensors and signal controllers. When the interfered devices and
the VFD are in the same control cabinet or in a short distance, radiation interference and thus malfunction
may easily occur. In this case, we recommend the following solutions: Try not to put the signal devices
and the VFD in the same cabinet and keep the signal devices away from the interference source; use
shielded twisted pairs for the signal cables and ground the shielded layer 360 degrees reliably.
Near-field induction transmits interference via near-field inductive coupling among cables. Generally, the
power cable and the signal cable are too close. In this case, you can adopt the following solutions:
Arrange the signal cable and the power cable separately; keep the signal cable away from the power
cable; use the shielded cables and ground the shielded layer 360 degrees reliably.
The signal devices should be grounded separately. To avoid common ground interference, do not ground
the signal devices with the VFD together.
B.2.2 Harmonic interference
Harmonic interference transmits interference in two ways: interfere the motor through the output port and
thus influence the service life of the motor; interfere other devices through the power port. In this case,
you can be adopt the following solutions: Install the reactor at the output port of the VFD; install RC
absorber at the output port of the VFD; in the case of severe conditions, suggest installing the LC sine
filter at the output port; install the reactor at the input power port, for four-quadrant VFD, install the LC
sine filter at the input power port; increase the carrier frequency appropriately. (Cautions: Too high carrier
frequency will increase temperature rise, electromagnetic noise and leakage current.)
-311-