Inverter-Generated Noise And Reduction Techniques - Mitsubishi Electric FR-E520 Instruction Manual

2.3.3

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
• 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 45) to signal cables.
• Earth (ground) the shields of the detector connection and control signal cables with
cable clamp metal.
INSTALLATION AND WIRING
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