Mitsubishi Electric FR-A700 Series, Technical Manual

Page: 41 / 550

34
SPECIFICATIONS
1.4 Information on use of external terminals
1.4.1 Switching the inverter power ON/OFF (R/L1, S/L2, T/L3)
(common
)
(1) No-fuse breaker and magnetic contactor
on the inverter power supply side
1) Install a specified moulded case circuit breaker
(MCCB) on the power receiving side to protect the
wiring to the inverter. An MCCB of greater
capacity may be required as compared to
commercial power operation because of the low
power factor of the power supply resulting from
the distorted input current in the inverter input
power supply side. Refer to page 526)
2) It is recommended to install a magnetic contactor
on the inverter power supply side to ensure safety
at fault occurrence. (See the circuit in the lower
right.) The circuit should be made up to protect
the inverter from any accident etc. that may be
caused by automatic restart when the power is
restored without magnetic contactor after power
failure.
3) Start and stop the motor by switching ON/OFF the
STF or STR signal. If the MC is used to stop the
motor, the motor coasts to a stop because
regenerative braking inherent in the inverter is not
applied. If the MC is used to start the motor during
coasting when, for example, load inertia is
extremely large, the protective circuit (overvoltage
E.OV1 to E.OV3) may be activated to shut off the
inverter output.
When performing Jog operation, the MC must not
be used to start and stop the motor. Otherwise,
slow response will result because of a start delay
due to the initial reset time (approximately 1s)
after power ON.
4) In case of the forced cooling, the cooling fan starts
rotating as soon as the power is switched ON.
However, cooling fan operation selection [
Pr. 244
Cooling fan operation selection
] may also be used to
exercise cooling fan ON-OFF control.
* When the power supply is 400V class, install a step-
down transformer.
common
The MC in the inverter power supply side can be
used to start and stop the motor. However, the
MC must not be used frequently to start and stop
the motor as repeated inrush current generated at
power ON will shorten the life of the converter
section of the inverter.
common
Magnetic contactor used in the power supply side
No magnetic contactor in the power supply side
(automatic restart prevented when power is restored)
M
C
T
IM
MCCB
R/L1
S/L2
T/L3
F
T ON
Coasting interlock timer
STF (STR)
SD
Motor
U
V
W
Inverter
MC
MC
OFF
MC
B1(B)
C1(C)
T *
Power
supply
[Operation preparation]
R
A
C
R
IM
MCCB
R/L1
S/L2
T/L3
F
Stop Start
RA
STF (STR)
SD
Motor
U
V
W
Inverter
CR
T
*
Power
supply