Справочник Пользователя для Mitsubishi Electronics FR-A500

38

Some noises enter the inverter to malfunction it and others are radiated by the inverter to malfunction

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 inverters chops outputs at high carrier

frequency, that could generate noise. If these noises cause peripheral devices to malfunction, measures

should be taken to suppress the noise. These techniques differ slightly depending on noise propagation

paths.

1) Basic techniques

•

 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 pair shielded cables for the detector connection and control signal cables, and connect the

sheathes of the shielded cables to terminal SD.

•

 Earth (Ground) the inverter, motor, etc. at one point.

2) Measures against noises which enter and cause misoperation of the inverter

When devices that generate many noises (which use magnetic contactors, magnetic brakes, many relays,

for example) are installed near the inverter and the inverter may be effected by noises, the following

measures must be taken:

•

 Provide surge suppressors for devices that generate many noises to suppress noises.

•

 Fit data line filters (refer to page 40) to signal cables.

•

 Earth (Ground) the shields of the detector connection and control signal cables with cable clamp metal.

3) Techniques to reduce noises that are radiated by the inverter to malfunction peripheral devices.

Inverter-generated noises are largely classified into those radiated by the cables connected to the inverter

and inverter main circuit (I/O), those electromagnetically and electrostatically inducted to the signal cables

of the peripheral devices close to the main circuit power supply, and those transmitted through the power

supply cables.

Air-propagated
noise

Magnetic induction
noise

Static induction
noise

Cable-propagated
noise

Noise directly radi-
ated by inverter

Noise radiated by
power cables

Noise radiated by
motor cables

Noise propagated
through power 
cables

Earth(ground) cable
dueto leakage
current

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Path 4),5)

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Path 6)

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Path 1)

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Path 2)

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Path 3)

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Path 7)

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Path 8)

Inverter-generated
noise

IM

In-

verter

Sensor power supply

Receiver

Instrument

Telephone

Motor

Sensor

5)

7)

2)

1)

7)

3)

2)

8)

3)

4)

6)