Select an MCCB according to the power supply capacity.
Install one MCCB per inverter.
For the use in the United States or Canada, provide the appropriate UL and cUL listed fuse or UL489
molded case circuit breaker (MCCB) that is suitable for branch circuit protection. (Refer to the
Magnetic contactor is selected based on the AC-1 class. The electrical durability of magnetic
contactor is 500,000 times. When the magnetic contactor is used for emergency stops during
motor driving, the electrical durability is 25 times.
If using an MC for emergency stop during motor driving, select an MC regarding the inverter input
side current as JEM1038-AC-3 class rated current. When using an MC on the inverter output side
for commercial-power supply operation switching using a general-purpose motor, select an MC
regarding the rated motor current as JEM1038-AC-3 class rated current.
The above shows a selection example for the ND rating. For selecting the SLD rating, LD rating, or
HD rating, refer to the Technical News (MF-X-121) contained in the enclosed CD-ROM.
When the inverter capacity is larger than the motor capacity, select an MCCB and a magnetic
contactor according to the inverter model, and select cables and reactors according to the motor
When the breaker on the inverter's input side trips, check for the wiring fault (short circuit), dam-
age to internal parts of the inverter etc. The cause of the trip must be identified and removed
before turning ON the power of the breaker.
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Installation of the breakers
Installation and wiring