Chapter 3 Electrical Wiring｜VP3000
142
3-9-4-3 Induction Noise Prevention
In addition to install the EMC filter to suppress induction noise from the output side, you can also
consolidate the wiring in a grounded metal pipe for the same purpose. If the signal cable is over 30
cm away from the drive, the influence of induction noise will be reduced. Be sure to ground the
metal pipe.
3-9-5 Zero Phase Reactor (choke)
Install a zero-phase reactor on the input or output side can also reduce the interference. Due to the
large current passing through the power input/ output line, be more attention to the saturation of the
magnetic core. Due to the large load current on the zero-phase reactor on the power input/ output
line, the ideal material is the composite magnetic powder core. This material is highly anti-saturated,
its resistivity is several times larger than pure metal magnetic material; therefore, it can be applied in a
higher frequency band. You can also increase the number of turns to obtain high impedance
capability.
Zero phase reactor installation position diagram:
1. Install at the cable between the power supply and the EMC filter.
2. Install at the cable between the EMC filter and the drive.
3. Install at the cable between the drive and the motor.
Figure 3-110
Harmonic Interference
The load of the AC motor drive is a non-linear load and generates different components of harmonic
current according to the design of the input rectifier. The harmonic current generally needs to be
limited within a certain range. This is to ensure that the harmonic voltage and current distortion of the
power grid do not exceed the specified range, so as to avoid affecting other equipment. Generally
speaking, the drive with built-in DC reactor can effectively suppress the harmonic current (Total
Harmonic Current Distortion, THID) within a certain range, which can also reduce the distortion of
harmonic voltage (Total Harmonic Voltage Distortion, THVD).
3-9-6 Reactors
In the input circuit of the drive, harmonic with lower frequency (5, 7, 9 and 11 times) has higher
proportion. In addition to possibly interfering with the normal operation of other equipment, they also
consume a large amount of reactive power and greatly reduce the power factor of the line.
Connecting reactors in series in the input circuit is an effective way to suppress lower-order harmonic
current.
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