App. A Advantageous Use of Inverters (Notes on Electrical Noise)
A-8
[3] Noise prevention examples
Table A-2 lists examples of the measures to prevent noise generated by a running inverter.
Table A-2 Examples of Noise Prevention Measures
No.
Tar ge t
device
Problem Noise prevention
Notes
1 AM
radio
When operating an inverter, noise
enters into an AM radio broadcast
(500 to 1500 kHz).
Figure A-11
<Possible cause>The AM radio
may receive noise radiated from
wires at the power supply and
output sides of the inverter.
1) Install an LC filter at the power
supply side of the inverter. (In
some cases, a capacitive filter
may be used as a simple
method.)
2) Install a metal conduit wiring
between the motor and
inverter.
Figure A-12
Note: Minimize the distance
between the LC filter and
inverter as short as
possible (within 1 m).
1) The radiation noise
of the wiring can be
reduced.
2) The conduction
noise to the power
supply side can be
reduced. Or use
shielded cables.
Note: Sufficient
improvement
may not be
expected in
narrow regions
such as between
mountains.
2 AM
radio
When operating an inverter, noise
enters into an AM radio broadcast
(500 to 1500 kHz).
Figure A-13
<Possible cause>The AM radio
may receive noise radiated from
the power line at the power supply
side of the inverter.
1) Install inductive filters at the
input and output sides of the
inverter.
Figure A-14
The number of turns of the
zero-phase reactor should be
as large as possible. In
addition, wiring between the
inverter and the zero-phase
reactor should be as short as
possible. (Within 1 m)
2) When further improvement is
necessary, install LC filters.
Figure A-15
1) The radiation noise
of the wiring can be
reduced.
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