INSTALLATION AND WIRING
33
2.3.2 Inverter-generated noise and reduction techniques
Some noises enter the inverter causing it to incorrectly operate, and others are
radiated by the inverter causing misoperation of peripheral devices. Though the
inverter is designed to be insusceptible to noise, it handles low-level signals, so it
requires the following basic measures to be taken. Also, since the inverter chops the
output at high carrier frequencies, it could generate noise. If these noises cause
peripheral devices to misoperate, measures should be taken to suppress noise. The
measures differ slightly depending on noise propagation paths.
1) Basic measures
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Do not run the power cables (I/O cables) and signal cables of the inverter in
parallel with each other and do not bundle them.
!
Use twisted shield cables for the detector connecting and control signal cables
and connect the sheathes of the shield cables to terminal SD.
!
Earth (Ground) the inverter, motor, etc. at one point.
2) Measures against noise which enters and causes misoperation of the inverter
When devices which generate noise (devices which use magnetic contactors,
magnetic brakes, many relays, for example) are installed near the inverter, the
inverter may misoperate due to noise. The following measures must be taken:
!
Provide surge suppressors for devices that generate noise to suppress noise.
!
Fit data line filters (Refer to page 36) to signal cables.
!
Ground the shields of the detector connection and control signal cables with cable
clamp metal.
