25
Power-off and magnetic contactor
(MC)
2
INS
T
ALLA
TIO
N
A
ND
WIRING
2.5 Power-off and magnetic contactor (MC)
(1) Inverter input side magnetic contactor (MC)
On the inverter input side, it is recommended to provide an MC for the following purposes.
(
Refer to
page 3
for selection.))
1) To release the inverter from the power supply when the inverter's protective function is activated or when the drive
is not functioning (e.g. emergency stop operation).
2) To prevent any accident due to an automatic restart at restoration of power after an inverter stop made by a
power failure
3) The control power supply for inverter is always running and consumes a little power. When stopping the inverter
for an extended period of time, powering off the inverter will save power slightly.
4) To separate the inverter from the power supply to ensure safe maintenance and inspection work
The inverter's input side MC is used for the above purpose, select class JEM1038-AC3MC for the inverter input
side current when making an emergency stop during normal operation.
(2) Handling of the inverter output side magnetic contactor
Switch the magnetic contactor between the inverter and motor only when both the inverter and motor are at a stop.
When the magnetic contactor is turned on while the inverter is operating, overcurrent protection of the inverter and
such will activate. When an MC is provided to switch to a commercial power supply, for example, it is recommended
to use commercial power supply-inverter switchover operation
Pr. 135 to Pr. 139 (
Instruction Manual (applied))
.
REMARKS
The MC may be switched on/off to start/stop the inverter. However, since repeated inrush currents at power on will shorten the
life of the converter circuit (switching life is about 1000,000 times), frequent starts and stops must be avoided. Turn on/off the
inverter start controlling terminals (STF, STR) to run/stop the inverter.
• Inverter start/stop circuit example
As shown on the left, always use the start
signal (ON or OFF across terminals STF or
STR-SD) to make a start or stop.
*1
When the power supply is 400V class, install a
step-down transformer.
*2
Connect the power supply terminals R1/L11, S1/
L21 of the control circuit to the primary side of
the MC to hold an alarm signal when the
inverter's protective circuit is activated. At this
time, remove jumpers across terminals R/L1-
R1/L11 and S/L2-S1/L21. (Refer to page 19 for
removal of the jumper.)
Power
supply
MCCB
RA
U
V
A1
B1
C1
W
To the
motor
Inverter
MC
STF(STR)
T
*1
R/L1
S/L2
T/L3
R1/L11
S1/L21
*2
OFF
ON
MC
Stop
Operation
RA
MC
Operation preparation
Start/Stop
RA
MC
SD
Summary of Contents for FR-F700 Series
Page 134: ...MEMO ...
