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Name of
peripheral
equipment
Molded case
circuit breaker
Earth leakage
When connecting the inverter to the power supply, add a recommended
circuit breaker *
molded case circuit breaker and earth leakage circuit breaker* in the path
* With the
of power supply. Do not use the devices with the rated current out of the
exception of
recommenced range.
those
*With the exception of those exclusively designed for protection from
exclusively
ground faults
designed for
protection from
Fire could occur.
ground faults
An MC can be used at both the power input and output sides of the inverter.
Magnetic
At each side, the MC works as described below. When inserted in the output
contactor (MC)
circuit of the inverter, an MC can also switch the motor drive power source
between the inverter output and commercial power lines.
I At the power source side
Insert an MC in the power source side of the inverter in order to:
1) Forcibly cut off the inverter from the power source (generally,
2) Stop the inverter operation in an emergency when the inverter cannot
3) Cut off the inverter from the power source when the MCCB inserted in the
Note: When your system requires the motor(s) driven by the inverter to be
started/stopped with the MC, the frequency of the starting/stopping operation
should be once or less per hour. The more frequent the operation, the shorter
operation life of the MC and capacitor/s used in the DC link circuit due to
thermal fatigue caused by the frequent charging of the current flow. If this is
not necessary, start/stop the motor with the terminal commands (FWD),
(REV) and/or (HLD), or with the keypad.
I At the output side
Prevent externally turned-around current from being applied to the inverter
power output terminals (U, V, and W) unexpectedly. An MC should be used,
for example, if a circuit that switches the motor driving source between the
inverter output and commercial/factory power lines is connected to the
inverter.
Note:
secondary (output) circuits may break the IGBTs, MCs should be used in the
power control system circuits to switch the motor drive power source to the
commercial/factory power lines after the motor has come to a complete stop.
Also ensure that voltage is never mistakenly applied to the inverter output
terminals due to unexpected timer operation, or similar.
I Driving the motor using commercial power lines
MCs can also be used to switch the power source of the motor driven by the
inverter to a commercial power source.
Function and application
commercial/factory power lines) with the protection function built into the
inverter, or with the terminal signal line.
interpret the stop command due to internal/external circuit failures.
power source side cannot cut it off for maintenance or inspection
purpose. For the purpose only, it is recommended that you use an MC
capable of turning the MC on/off manually.
As application of high voltage external current to the inverter's
9-2
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