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Introduction of Shihlin Inverter
Introduction of Inverter
In general, signal wires (weak) and power lines (heavy) are located in the control cabinet. For
inverters, the electric line of force is divided into incoming lines and tail wires. For wiring, signal
wires and power lines should be distributed in different and closed region (within 20cm). Parallel
lines and interlace lines are strictly forbidden, and they should not be tied together. If the signal cable
must pass through the power lines, they have to be maintained at a 90 degree Angle to the power
lines. The parallel lines and interlace lines can not crisscross the power lines or be tied together if a
noise filter is installed; it will make coupled noises when electromagnetic noises pass through the
distributed capacitance. In this case, the noise filter will be out of action.
Generally, for same controllers with different electric equipments, such as inverter, filter, PLC,
measurement instruments, the transmitter electromagnetic noise to external and the bearing capacity
are not identical. These equipments have to be classified into strong noise quipments and noise
sensitive equipments. Similar equipments must be installed in the same area, while inhomogeneity
equipments must be kept at a distance greater than 20 cm.
2. Input noise filter, input and output magnet ring (zero-phase reactor)
Increase noise filter in the input terminal, which will isolate the inverter and other equipment, can
effectively reduce the conduction and radiation ability of the inverter. Install the input reactor as what
is recommended by this manaul with better
EMI Suppression.
Increase the ferrite of the input and
output terminals (refer to
Section 3.6.5
), and at the same time increase the zero-phase reactor (refer to
Section 3.6.5) and 4 turns Hitachi metals nano-magnetic ring to reduce the interference in motor side,
then can satisfy the limited value of conduction and radiation that is stated by the CE.
3. Shielding
Good shielding and grounding can greatly reduce inverter interference and improve the
anti-interference capacity of the inverter. Use the good electricity conducting sheet metal box sealing,
the inverter good contacts to metal and let the sheet metal grounded to satisfy the limits value of
radiation stated by the CE.
Input and output lines used cable with shielding, good grounding and shielding to satisfy the limits
value of radiation stated by the CE.
4. Grounding
Inverter at work must have a safe and reliable grounding. Grounding is not only for equipment safety,
but also the simplest, efficient and inexpensive method for solving the EMC problem, and therefore,
it should be prioritized. Please refer to the "terminal wiring" section.
5. Carrier Wave
The leakage current contains leakage currents from line to line or over the ground. It depends on the
size of the capacitance and the carrier frequency of the wiring system. When the carrier frequency is
higher, the motor cable will be longer, the cable cross-sectional area will be larger, and the leakage
current will be larger. Reduce the carrier frequency to effectively reduce the leakage current. When
using a long line of motor (50m or above), the output side should be connected to an AC reactor or a
sine wave filter. If the motor line is longer than 50 m, a reactor should be installed at every distance.
At the same time, carrier frequency reduction can effectively reduce the conduction and radiation
interference. The 5K carrier frequency can satisfy the limit value of the conduction and radiation
stated by the CE.
