Fuji Electric frenic mini series, User Manual

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A-4
Figure A.5 Electrostatic Noise
(3) Radiation noise
Noise generated in an inverter may be radiated through the air from wires (that act as antennas) at
the input and output sides of the inverter. This noise is called "radiation noise"
as shown below.
Not only wires but motor frames or control system panels containing inverters may also act as
antennas.
Figure A.6 Radiation Noise
A.3
Noise prevention
The more noise prevention is strengthened, the more effective. However, with the use of appropriate
measures, noise problems may be resolved easily. It is necessary to implement economical noise
prevention according to the noise level and the equipment conditions.
[ 1 ] Noise prevention prior to installation
Before inserting an inverter in your control panel or installing an inverter panel, you need to consider
noise prevention. Once noise problems occur, it will cost additional materials and time for solving
them.
Noise prevention prior to installation includes:
1) Separating the wiring of main circuits and control circuits
2) Putting main circuit wiring into a metal pipe (conduit pipe)
3) Using shielded wires or twist shielded wires for control circuits.
4) Implementing appropriate grounding work and grounding wiring.
These noise prevention measures can avoid most noise problems.