Table of Contents
Advertisement
Power-OFF and magnetic contactor (MC)
3.3
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 4 for selection.)
1) To release the inverter from the power supply when the fault occurs or when the drive is not functioning (e.g. emergency
stop operation). For example, MC avoids overheat or burnout of the brake resistor when heat capacity of the resistor is
insufficient or brake regenerative transistor is damaged with short while connecting an optional brake resistor.
2) To prevent any accident due to an automatic restart at restoration of power after an inverter stop made by a power failure
3) To separate the inverter from the power supply to ensure safe maintenance and inspection work.
Use the inverter input current as a reference for selection of an MC to perform an emergency stop during operation, and
select the MC conforming to JEM1038-AC-3 class rated operational current.
REMARKS
Since repeated inrush currents at power ON will shorten the life of the converter circuit (switching life is about 1,000,000 times.),
frequent starts and stops of the MC must be avoided. Turn ON/OFF the inverter start controlling terminals (STF, STR) to run/stop
the inverter.
Three-phase AC
power supply
Operation preparation
OFF
ON
MC
Start/Stop
MC
Start
Stop
RA
(2) Handling of 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 for switching to the commercial power supply, for example, switch it ON/OFF after the inverter and
motor have stopped.
48
Inverter
MCCB
MC
R/L1
S/L2
T/L3
T
*1
MC
RA
STF/STR
SD
RA
Inverter start/stop circuit example
As shown on the left, always use the start signal
U
Motor
V
(ON or OFF of STF/STR signal) to make a start
W
or stop.
When the power supply is 400V class, install a step-down
C
transformer.
B
A
Advertisement
Table of Contents
