Mitsubishi Electric FR-F720-00046 Instruction Manual page 63

Precautions for use of the inverter
(13) If the machine must not be restarted when power is restored after a power failure, provide a magnetic contactor in the
inverter's input side and also make up a sequence which will not switch on the start signal.
If the start signal (start switch) remains on after a power failure, the inverter will automatically restart as soon as the
power is restored.
(14) Instructions for overload operation
When performing an operation of frequent start/stop of the inverter, increase/decrease in the temperature of the
transistor element of the inverter may repeat due to a continuous flow of large current, shortening the life from thermal
fatigue. Since thermal fatigue is related to the amount of current, the life can be increased by reducing bound current,
starting current, etc. Decreasing current may increase the life. However, decreasing current will result in insufficient
torque and the inverter may not start. Therefore, increase the inverter capacity to have enough allowance for current.
(15) Make sure that the specifications and rating match the system requirements.
(16) If electromagnetic noise generated from the inverter causes frequency setting signal to fluctuate and motor rotation
speed to be unstable when changing motor speed with analog signal, the following countermeasures are effective.
· Do not run the signal cables and power cables (inverter I/O cables) in parallel with each other and do not bundle them.
· Run signal cables as far away as possible from power cables (inverter I/O cables).
· Use shield cables as signal cables.
· Install a ferrite core on the signal cable (Example: ZCAT3035-1330 TDK).
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