MITSUBISHI ELECTRIC FR-S520 - Manual (Page 27)

18
1.
5.6 Regarding the installation of the power factor improving reactor
When the inverter is installed near a large-capacity power transformer (500kVA or
more at the wiring length of 10m (32.81feet) or less) or the power capacitor is to be
switched, an excessive peak current will flow in the power supply input circuit,
damaging the converter circuit. In such a case, always install the power factor
improving reactor (FR-BEL or FR-BAL).
NFB
Inverter FR-BAL
Power
supply
R
S
T Z
Y
X
R<L
1
>
S<N>
T
U
V
W
P<+>P1
FR-BEL(*)
0 10
Wiring length (m)
500
1500
1000
Power s
uppl
y equ
ipme
nt
cap
a
ci
ty (kVA
)
Power factor
improving reactor
installation range
REMARKS
* When connecting the FR-BEL, remove the jumper across terminals P<+>-P1.
The wiring length between FR-BEL and inverter should be 5m (16.40feet)
maximum and as short as possible.
Use the cables which are equal in size to those of the main circuit. (Refer to page
11)
1 .5.7 Regarding 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 counter measures to be taken.
General counter measures
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, earth and
motor, through which leakage currents flow to cause the earth leakage circuit
breaker, earth 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 an earth leakage circuit breaker designed for suppression of
harmonics and surges, and use the electronic overcurrent protection built in the
inverter.