Mitsubishi Electric FR-A700 Instruction Manual page 521

Parameter
NOTES
Speed detection time (frequency search) changes according to the motor speed.
(maximum 500ms)
Frequency search errors can occur if the output capacity of the frequency inverter is one or
more classes higher than that of the motor or if the motor is a special model (e.g. with a fre-
quency rating above 60Hz). If this happens it is possible for over current error messages
(OCT) to be generated during motor acceleration. In such configurations flying restarts are
not possible and the frequency search function should not be used.
At motor frequencies of 10Hz or less the inverter accelerates from 0Hz to the set frequency.
If more than one motor is connected to the inverter in parallel the frequency search on auto-
matic restart does not work correctly and over current error messages (OCT) are likely. In
such configurations deactivate frequency search (set Pr. 162 to "1" or "11"). Then configure
by trial and error, starting with smaller values for Pr. 164 and larger values for Pr. 163 to find
out whether the motor can be started without an over current error (OCT).
Since the DC injection brake is operated instantaneously when the speed is detected at a
restart, the speed may reduce if the inertia moment (J) of the load is small.
When reverse rotation is detected when Pr. 78 = 1 (reverse rotation disabled), the rotation
direction is changed to forward rotation after decelerates in reverse rotation when the start
command is forward rotation. The inverter will not start when the start command is reverse
rotation.
FR-A700 EC
Operation selection at power failure
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