Shihlin electric SL3 Series, Руководство пользователя

Страница: 23 / 211

EMC installation instructions
INVERTER INTRODUCTION 21
3.5.4 EMC installation instructions
Just as other electrical and electronic equipment, an inverter is the source of electromagnetic interference and an
electromagnetic receiver when working with a power system. The amount of electromagnetic interference and noise is
determined by the working principles of an inverter. In order to guarantee the inverter working reliably in the
electromagnetic environment, it must have a certain ability of anti-electromagnetic interference in design. In order to
make the drive system work normally, please meet the following several aspects requirements in installation:
 Field wiring
Power line supply electric independently from power transformer, five or four core line are generally used, null line
and ground sharing a single line is forbidden.
Commonly signal wire (weak) and power wire (heavy) are in control cabinet, for the inverter, power wire is divided
into input line and output line. Signal wire is easily interfered by power wire, so that causing the misoperation of the
device. When wiring, signal wire and power wire should be distributed in different areas, parallel lines and
interlaced lines are forbidden at close range(within 20cm), and especially don’t bundle up the two lines. If the
signal cables must pass via the power lines, the two should keep 90 degree angle. Interlace lines and banding
together is also forbidden for the input and output line of power wire, especially on the occasions which noise filter
is installed. It will cause the coupling of electromagnetic noise via the distributed capacitance of the input and
output lines, thus the noise filter will out of action.
Generally a control cabinet has different electric equipment such as inverter, filter, PLC, measurement instrument,
their ability of emitting and bearing electromagnetic noise are diverse from each other, and this requires classifying
these equipment. The classification can be divided into strong noise equipment and noise sensitive equipment,
Install the similar equipment in the same area and, and keep a distance more than 20cm among inhomogeneous
equipments.
 Input noise filter, input and output magnet ring (Zero phase reactor)
Adding noise filter to the input terminal, the inverter will be isolated from the other equipment, and its ability of
conduction and radiation will be reduced effectively. By adding winding ferrite bead to the input and output terminal
and coordinating with internal filter, the inverters will have a better effect.
 Shielding
Good shielding and grounding can greatly reduce the interference of inverter, and can improve the
anti-interference ability of the inverter. Sealing off the inverter with the good conductive sheet metal and
connecting the sheet metal to ground, the radiation interference will be reduced effectively. To reduce the
interference of inverter and improve the anti-interference ability, cable with shielding layer should be used in input
and output and the both ends of it should be connected to ground. Shielding cable is suggested to be used in
control connecting and communication connecting of the inverter external terminals under bad electromagnetic
environment. Generally, the both ends of shielding layer should be connected to the control /communication
ground, and they can also be connected to ground.
 Grounding
The inverter must be connected to the ground safely and reliably. Grounding is not only for equipment and
personal safety, but also the simplest, the most efficient and the lowest cost method to solving the EMC problem,
so it should be prioritized. Please refer to the section of “3.7 Terminal wiring".

Carrier wave
The leakage current contains the leakage current from line to line or over the ground. It depends on the size of the
distributed capacitance when wiring and the carrier frequency of the frequency. The higher the carrier frequency,
the longer the motor cable, and the larger the cable cross-sectional area is, the larger the leakage current is.
Reducing the carrier frequency can effectively reduce the leakage current. When the motor line is long (50m
above), the output side should be installed with ac reactor or sine wave filter, when the motor line is longer, a
reactor should be installed every other distance. At the same time, reducing carrier frequency can effectively
reduce the conduction and radiation interference.