2.3.2 Japanese harmonic suppression guideline
Harmonic currents flow from the inverter to a power receiving point via a power
transformer. The harmonic suppression guideline was established to protect other
consumers from these outgoing harmonic currents.
1) "Harmonic suppression guideline for household appliances and general-purpose
This guideline was issued by the Ministry of International Trade and Industries in
September, 1994 and applies to 200V class inverters of 3.7kW (5HP) or less*. By
installing the FR-BEL or FR-BAL power factor improving reactor, inverters comply
with the "harmonic suppression techniques for transistorized inverters (input current
20A or less)" established by the Japan Electrical Manufacturers' Association.
Therefore install the optional reactor for the 200V class, 3.7kW (5HP) or less
* For the single-phase 100V class, the guideline applies to 0.75kW and less models.
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
y 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.
y Use twisted shield cables for the detector connecting and control signal cables
and connect the sheathes of the shield cables to terminal SD.
y 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:
y Provide surge suppressors for devices that generate noise to suppress noise.
y Fit data line filters (refer to page 39) to signal cables.
y Ground the shields of the detector connection and control signal cables with cable
INSTALLATION AND WIRING