App. A Advantageous Use of Inverters (Notes on Electrical Noise)
A-5
App.
[2] Implementation of noise prevention measures
There are two types of noise prevention measures--one for noise propagation routes and the other for noise
receiving sides.
The basic measures for lessening the effect of noise at the receiving side include:
1. Separating the main circuit wiring from the control circuit wiring, avoiding noise effect.
The basic measures for lessening the effect of noise at the generating side include:
2. Inserting a noise filter that reduces the noise level.
3. Applying a metal conduit pipe or metal control panel that will confine noise, and
4. Applying an insulated transformer for the power supply that cuts off the noise propagation route.
Table A-1 lists the noise prevention measures, their goals, and propagation routes.
Table A-1 Noise Prevention Measures
Goal of noise
prevention measures
Conduction
route
Noise prevention measures
Make it more difficult to
receive noise
Cutoff noise conduction
Confine noise
Reduce noise level
Conduction noise
Induction noise
Radiation noise
Separate main circuit from control circuit Y Y
Minimize wiring distance Y Y Y Y
Avoid parallel and bundled wiring Y Y
Use appropriate grounding Y Y Y Y
Use shielded wire and twisted shielded wire Y Y Y
Use shielded cable in main circuit Y Y
Cabling and
installation
Use metal conduit pipe Y Y Y
Appropriate arrangement of devices in panel Y Y Y
Control panel
Use metal control panel Y Y Y
Line filter Y Y Y Y
Anti-noise
devices
Insulation transformer Y Y Y
Use a passive capacitor for control circuit Y Y Y
Use ferrite core for control circuit Y Y Y
Measures at
noise receiving
sides
Line filter Y Y
Separate power supply systems Y Y Y
Others
Lower the carrier frequency Y Y Y Y
Y indicates effective measure. Blank indicates ineffective measure.
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