Mitsubishi Electronics FR-S500 Regarding noise and the installation of a noise filter

Main circuit terminals

1.2.8Regarding noise and the installation of a noise filter

Some noise enters the inverter causing it to malfunction and others are generated by the inverter causing the malfunction of peripheral devices. Though the inverter is designed to be insusceptible to noise, it handles low-level signals, so it requires the following general countermeasures to be taken.

(1) General countermeasures

•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.

•Ground the inverter, motor, etc. at one point.

•Capacitances exist between the inverter's I/O wiring, other cables, ground and motor, through which leakage currents flow to cause the earth leakage circuit breaker, ground leakage relay and external thermal relay to operate unnecessarily. To prevent this, take appropriate measures, e.g. set the carrier frequency in Pr. 72 to a low value, use a ground leakage circuit breaker designed for suppression of harmonics and surges, and use the electronic thermal relay function built in the inverter.

•The input and output of the inverter main circuit include high-degree harmonics, which may disturb communication devices (AM radios) and sensors used near the inverter. In this case, install a FR-BIF(-H) optional radio noise filter (for use on the input side only) or FR-BSF01 line noise filter to minimize interference.

<Noise reduction examples>

Install filter FR-BSF01	Control		Reduce carrier
	box		frequency.		Install filter FR-BSF01
on inverter's input side.					on inverter's output side.
Inverter	FR-		Inverter	FR-
	BSF01			BSF01	IM	Motor
power supply
Install filter FR-BIF					Use 4-core cable for motor
on inverter's input side.	FR-BIF
					power cable and use one
Separate inverter and power line
					cable as ground cable.
by more than 30cm (3.94inches)
and at least 10cm (11.81inches)				Use twisted pair shielded cable.
from sensor circuit.
					Sensor
		Power
Control
power supply		supply
		for sensor

Do not ground control	Do not ground shield but connect
box directly.	it to signal common cable.

Do not ground control cable.

18