Fuji Electric FRENIC-HVAC User Manual page 727

[ 2 ] Types of noise
Noise generated in an inverter is propagated through the main circuit wiring to the
power supply and the motor so as to affect a wide range of applications from the power
supply transformer to the motor. The various propagation routes are shown in Figure
A.2. According to those routes, noises are roughly classified into three types--conduction
noise, induction noise, and radiation noise.
Figure A.2 Noise Propagation Routes
(1) Conduction noise
Noise generated in an inverter may propagate through the conductor and power supply
so as to affect peripheral devices of the inverter (Figure A.3). This noise is called
"conduction noise." Some conduction noises will propagate through the main circuit .
If the ground wires are connected to a common ground, conduction noise will propagate
through route . As shown in route , some conduction noises will propagate through
signal lines or shielded wires.
Figure A.3 Conduction Noise
(2) Induction noise
When wires or signal lines of peripheral devices are brought close to the wires on the
input and output sides of the inverter through which noise current is flowing, noise will
be induced into those wires and signal lines of the devices by electromagnetic induction
(Figure A.4) or electrostatic induction (Figure A.5). This is called "induction noise" .
Figure A.4 Electromagnetic Induced Noise
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