Mitsubishi Electric FATEC FR-A800 Manual page 131

7
REVIEW OF INSTALLATION ENVIRONMENT
(2) Connection of the main circuit
Since the main circuit is a power circuit, incorrect connection may not only damage the inverter
but also pose a risk to operators. The following figure shows points likely to fail.
Do not apply the voltage
that exceeds the permissible
voltage specification of the
inverter.
(3)
(1)
Do not connect terminal (2) of the
frequency setting potentiometer to
terminal 10 or 5 of the inverter.
(3)
(2)
(1)
Example of error
7.3 Problems and measures when using inverter
126
Power supply
MCCB
MC
R S T
Inverter
10
(2)
2
5
U V W
MC
F
IM
Motor
10 10
(3)
(2)
2 2
5 5
(1)
Fig. 7.35 Main circuit connection
Do not repeat starting and stopping frequently with this
magnetic contactor (MC).
Basic sequence example when MC is not set
MCCB
200 V
power
supply
F
Start
CR1
Stop
The inverter breaks when power supply is
connected to terminals U, V, and W
by mistake.
Electric and mechanical interlock must be
provided so that MC
turn on simultaneously. Otherwise,
undesirable current power (power supply
is applied to terminals U, V, and W)
occurs (including arc jumper).
Check that the phase rotation of
MC
C
commercial power supply is in the
order of R → S → T.
If the wiring distance is long, especially the voltage drop in
the low frequency cable will cause the motor torque to
decrease. Wire them using thick cables. When connecting
directly to the inverter terminal is not possible since the cable i
s too thick, use a junction terminal block.
Precautions not to damage the inverter
The following usages may damage the inverter.
1) When the MC at the power supply side is turned ON/OFF
frequently.
2) When the power supply cable is connected to the motor
connecting terminal of the inverter, and power is turned on.
[Misconnection]
3) When an inverter for 200 V is connected to the power supply
for 400 V.
4) When the inverter is connected near a large-capacity
transformer in a short distance.
(Reactor installation is the measure.)
R
S
T
CR 2
C
R STF (STR)
1
C
SD
R
2
and MC do not
C F