Mitsubishi Electric FR-F740 EC Instruction Manual page 95

Operation
● 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.
● When the motor speed is unstable, due to change in the frequency setting signal caused by
electromagnetic noises from the inverter, take the following measures when applying the
motor speed by the analog signal:
– 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).
● Instructions for overload operation
When performing 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 insuffi-
cient torque and the inverter may not start. Therefore, increase the inverter capacity to have
enough allowance for current.
● Make sure that the specifications and rating match the system requirements.
FR-F700 EC
Precautions for use of the inverter
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