Mitsubishi Electric FR-F802 Instruction Manual page 70

Checkpoint
A countermeasure is provided for an
overload operation.
The specifications and rating match
the system requirements.
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). 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. -
PRECAUTIONS FOR USE OF THE INVERTER
Checklist before starting operation
Refer
to page
-
Check
by user
3
69