Shihlin Inverter Introduction
Inverter Introduction
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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 through 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 through the distributed capacitance of the input and output lines, thus the noise filter
will out of action.
Generally a control cabinet has different electric equipments 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 equipments. The classification
can be divided into strong noise equipment and noise sensitive equipment, Install the similar
equipments in the same area and, and keep a distance more than 20cm among
inhomogeneous equipments.
2. 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
equipments, and its ability of conduction and radiation will be reduced effectively. The better
EMI suppression effect will be obtained by installing the input reactor recommended by this
manual. By adding winding ferrite bead to the input and output terminal and coordinating
with internal filter, the inverters will have a better effect.
3. 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.
4. 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 "terminal wiring".
5. 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.
