Introduction of Shihlin Inverter
Introduction of Inverter
13
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 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 classifing 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. 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
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 leakage current from line to line or
over ground. It depends on the
size of distributed capacitance when wiring and carrier frequency of frequency. The higher carrier
frequency, longer the motor cable, and 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, and the limits
value of the conduction and radiation which CE declared can be met in 5K carrier frequency.
