Mitsubishi Electric A800 Plus Instruction Manual page 88

Checkpoint
A countermeasure is provided for an
overload operation.
The specifications and rating match
the system requirements.
Countermeasures are taken against
electrical corrosion on the motor
bearing.
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Recommended common mode choke: FT-3KM F series FINEMET
is a registered trademark of Hitachi Metals, Ltd.
Countermeasure
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).
Make sure that the specifications and rating match the system requirements. -
When a motor is driven by the inverter, axial voltage is generated on the
motor shaft, which may cause electrical corrosion of the bearing in rare
cases depending on the wiring, load, operating conditions of the motor or
specific inverter settings (high carrier frequency and EMC filter ON). Contact
your sales representative to take appropriate countermeasures for the motor.
The following shows examples of countermeasures for the inverter.
• Decrease the carrier frequency.
• Turn OFF the EMC filter.
• Provide a common mode choke on the output side of the inverter.
effective regardless of the EMC filter ON/OFF connector setting.)
PRECAUTIONS FOR USE OF THE INVERTER
Checklist before starting operation
®
common mode choke cores manufactured by Hitachi Metals, Ltd. FINEMET
Refer Check
to page by user
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