5-48
F codes
E codes
C codes
P codes
H codes
A codes
b codes
r codes
J codes
d codes
U codes
y codes
Chap. 5 FUNCTION CODES
Restart mode after momentary power failure (Frequency fall rate) (H14)
During restart after a momentary power failure, if the inverter output frequency and the idling motor speed cannot be
harmonized with each other, an overcurrent will flow, activating the overcurrent limiter. If it happens, the inverter
automatically reduces the output frequency to match the idling motor speed according to the reduction rate (Frequency
fall rate: Hz/s) specified by H14.
Data for H14 Inverter’s action for the output frequency fall
0.00 Follow the deceleration time specified
0.01 to 100.00 (Hz/s) Follow data specified by H14
999
Follow the setting of the PI controller in the current limiter.
(The PI constant is prefixed inside the inverter.)
If the frequency fall rate is too high, regeneration may take place at the moment the motor rotation matches
the inverter output frequency, causing an overvoltage trip. On the contrary, if the frequency fall rate is too
low, the time required for the output frequency to match the motor speed (duration of current limiting action)
may be prolonged, triggering the inverter overload prevention control.
Restart after momentary power failure (Continuous running level) (H15)
Continuity of running (P and I) (H92, H93)
• Trip after decelerate-to-stop
If a momentary power failure occurs when F14 is set to "2" (Trip after decelerate-to-stop), the inverter enters the control
sequence of the decelerate-to-stop when the DC link bus voltage drops below the continuous running level specified by
H15.
Under the decelerate-to-stop control, the inverter decelerates its output frequency keeping the DC link bus voltage
constant using the PI processor. P (proportional) and I (integral) components of the PI processor are specified by H92
and H93, respectively.
For normal inverter operation, it is not necessary to modify data of H15, H92 or H93.
• Continue to run
If a momentary power failure occurs when F14 is set to "3" (Continue to run), the inverter enters the control sequence
of the continuous running when the DC link bus voltage drops below the continuous running level specified by H15.
Under the continuous running control, the inverter continues to run keeping the DC link bus voltage constant using the
PI processor.
P (proportional) and I (integral) components of the PI processor are specified by H92 and H93, respectively.
For normal inverter operation, it is not necessary to modify data of H15, H92 or H93.
α
Power supply voltage
22 kW or below 30 kW or above
200 V class series 5 V 10 V
400 V class series 10 V 20 V
Even if you select "Trip after decelerate-to-stop" or "Continue to run," the inverter may not be able to do so
when the load's inertia is small or the load is heavy, due to undervoltage caused by a control delay. In such
"Continue to run" is selected, the inverter saves the output frequency being applied when the undervoltage
alarm occurred and restarts at the saved frequency after a recovery from the momentary power failure.
When the input power voltage for the inverter is high, setting the continuous running level high makes the
control more stable even if the load's inertia is relatively small. Raising the continuous running level too high,
however, might cause the continuous running control activated even during normal operation.
When the input power voltage for the inverter is extremely low, continuous running control might be activate
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