40
INSTALLATION AND WIRING
•
Data line filter
Noise entry can be prevented by providing a data line filter for the detector cable etc.
•
Data examples
*Noise terminal voltage: Represents the magnitude of noise propagated from the inverter to the power supply.
zExample of counter measures against noise
By decreasing the carrier frequency, the noise terminal voltage*
can be reduced. Use Pr. 72 to set the carrier frequency to a low
value (1kHz).
Though motor noise increases at a low carrier frequency,
selection of Soft-PWM in Pr. 240 will make it unoffending.
Differences between Noise Terminal Voltages
at Different Carrier Frequencies
By decreasing the carrier frequency, noise will be about as low as
that of our conventional FR-Z200 series.
By using shielded cables as signal cables, induction noise can be
reduced greatly (to 1/10 - 1/100). Induction noise can also be
reduced by moving the signal cables away from the inverter output
cables. (Separation of 30cm reduces noise to 1/2-1/3.)
By fitting the FR-BSF01 or BLF on the inverter output side, induction
noise to the signal cables can be reduced.
Noise Terminal Voltage of Inverter and Example
of Its Reduction by Noise Filters
Noise Induced to Signal Cables by Inverter Output Cables
0.1 0.3 0.5 1 3 5 10 30
20
60
80
100
120
0
FR-A520-3.7K
fc=0.7kHz
fc=14.5kHz
fc=2.0kHz Soft-PWM(Factory setting)
FR-A220E-3.7k fc=(14.5kHz)
Noise terminal voltage (dB)
Noise frequency (MHz)
Conditions
Motor: 3.7kW
Average terminal voltage 0dB=1
µ
V
120dB=1V
0.1 0.3 0.5 1 3 5 10 30
20
60
80
100
120
0
FR-A520-3.7K (fc=0.7kHz)
FR-Z220-3.7K
Noise frequency (MHz)
Noise terminal voltage (dB)
Conditions
Motor:3.7kW
Average terminal voltage 0dB=1
µ
V
120dB=1V
20
40
60
80
100
10
0
20 30 40 50
5cm
d(cm)
FR-BLF
FR-BSF01
(4T)
Line-to-line distance, d (cm)
Induction voltage (dB)
Parallel cable
Twisted pair cable
Coaxial cable
Inverter
Motor
Terminal
Measuring instrument
Conditions
Inverter: FR-A520-3.7K
Motor: SF-JR 4P 3.7kW
Output frequency: 30Hz
Noise form: Normal mode
FR-
BLF
FR-
BIF
FR-
BLF
Install filter (FR-BLF,FR-
BSF01) to inverter input side.
Control box
Reduce carrier
frequency.
Install filter (FR-BLF,FR-BSF01)
to inverter output side.
Use 4-core cable for motor
power cable and use one
cable as earth (ground) cable.
Use twisted pair
shielded cable.
Sensor
Do not earth (ground) shield but connect
it to signal common cable.
Do not earth (ground) control box directly.
Do not earth (ground) control cable.
Control power
supply
Install filter FR-BIF to
inverter input side.
nverter power
upply
Power
supply for
sensor
Inverter
Motor
Separate inverter and power line
30cm or more (at least 10cm)
from sensor circuit.
