Mitsubishi FR-F500 Instruction Manual page 45

Data examples
By decreasing the carrier frequency, noise will be
about as low as that of our conventional FR-Z200
series.
Noise Terminal Voltage of Inverter and Example
of Its Reduction by Noise Filters
Conditions
! Motor:3.7kW (5HP)
! Average terminal voltage 0dB=1 V
120
FR-Z220-3.7K
100
80
60
20
0
0.1 0.3 0.5 1
Noise frequency (MHz)
*Noise terminal voltage: Represents the magnitude of noise propagated from the inverter to the power supply.
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
Conditions
! Motor: 3.7kW (5HP)
! Average terminal voltage 0dB=1 V
120
FR-F520-3.7K
100
fc=0.7kHz
80
fc=14.5kHz
60
fc=2.0kHz Soft-PWM(Factory setting)
20
0
0.1 0.3 0.5 1
Noise frequency (MHz)
120dB=1V
FR-F520-3.7K(fc=0.7kHz)
3 5 10 30
INSTALLATION AND WIRING
120dB=1V
FR-A120E-3.7K fc=14.5kHz
3 5 10 30
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 (11.81inches) 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 Induced to Signal Cables by Inverter Output
Cables
100
Parallel cable
80
Twisted pair cable
60
40
Coaxial cable
20
0
10 20 30 40
34
Conditions
! Inverter: FR-F520-3.7K
! Motor: SF-JR 4P 3.7kW (5HP)
! Output frequency: 30Hz
! Noise form: Normal mode
5cm
d(cm)
Inverter Motor
FR-BLF
Terminal
FR-BSF01
(4T)
Measuring instrument
Line-to-line distance, d (cm)
50
2