Mitsubishi Electric Freqrol-A100 Instruction Manual page 182

Example of. measures against noises
Install f~lter (FR-BLF, FR-
lnverter power
_h_
supply
Use 4-core cable for motor
lnverter input s~de
power cable and use one
cable as ground cable
Separate Inverter and power
lme 30cm or more
(at
least
10cm) from sensor clrcult
n
Control power
+
0
------------------
-
SUPPl Y
sensor
Do not ground shleld but connect
Do not ground control box d~rectly
~t to s~gnal common cable
Do not ground control cable
6.1.2 Leakage Current
Because of static capacitances existing in the inverter I10 wiring and motor, leakage current flows
through them. Since its value depends on the static capacitances, carrier frequency, etc., leakage
current increases when the low-noise type inverter,is used.
In this case, take the following measures.
1) To-Ground leakage current
-
Leakage current may flow into not only the
inverter's own line but also the other line
through the earth cable, etc. This leakage
current may operate earth leakage circuit
breakers and ground leakage relays un-
necessarily.
- . ,
.
of the inverter. Note that'rnotor noise
'
*:
F o r inforrnat~on o n selectmg the earth leakage circuit breaker,
increases.
see page
167.
By using earth leakage circuit breakers compatible with harmonics and surges (e.g.
Mitsubishi's New Super NV series) in the inverter's own line and other line, operation
-
can be
performed with low noise (with the carrier frequency kept high).
NV I
supply
r round leakagef
- - -
-
-
clrcult
breaker
Ground
leakage
clrcult
breaker
L - -
- - - - - - - - -
Measures
To-around leakage current data example
Leakage Current Sneak Path
Decrease the carrier freauencv (Pr.
72)
0 50 100 Output s ~ d e wlrlng
length ( m )
400
2
300
- .-
c
E
;
.OO
1
To-Ground Leakage Current versus
Carrier Frequency and Wiring Length
hgher motor c a p a c ~ t y leads t o larger leakage current.
arger leakage current occurs I n
400V class t h a n i n 200V
lass.
I
C o n d ~ t ~ o n s
,
Carr~er frequency
.
Motor
.SF-J 3 7kW 4P
14
5kHz
(FR-A14OE)
.
Output frequency
...
3OH
Motor
capacity
' ( k ~ )
"
To-Ground Leakage Current versus Motor Capacity
P L /
-2kHz (FR-A14OE)
/'
1OkHz (FR-A140E)