Mitsubishi Electric FR-A862 Instruction Manual page 63

Checklist before starting operation
Checkpoint
EMC precautions are taken for the
frequency setting signals.
A countermeasure is provided for an
overload operation.
The specifications and rating match
the system requirements.
62
PRECAUTIONS FOR USE OF THE INVERTER
Countermeasure
If electromagnetic noise generated from the inverter and the converter unit
causes frequency setting signal to fluctuate and the motor rotation speed to be
unstable when changing the motor speed with analog signals, the following
precautions are effective:
• Do not run the signal cables and power cables (inverter and converter unit 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 and
converter I/O cables).
• Use shielded cables.
• Install a ferrite core on the signal cable.
When performing frequent starts/stops by the inverter, rise/fall in the
temperature of the transistor element of the inverter will repeat due to a
repeated 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 current at locked condition, starting current, etc. Reducing current
may extend the service life but may also cause torque shortage, which leads to
a start failure. Adding a margin to the current can eliminate such a condition.
For an induction motor, use the inverter and the converter unit of a higher
capacity (up to two ranks). For a PM motor, use the inverter and the converter
unit, and PM motor of higher capacities.
Make sure that the specifications and rating match the system requirements.
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