Fuji Electric FRENIC-HVAC User Manual page 375

Restart after momentary power failure (Continuous running level) (H15)

Continuity of running (P and I) (H92, H93)
• Continue to run (F14 = 3)
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.
30 HP or below
230 V class series 5 V
460 V class series 10 V
575 V class series 14V
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 a case, when "Trip after
decelerate-to-stop" is selected, the inverter allows the motor to coast to a stop; when
"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 activated even during normal operation, at the beginning of
acceleration or at an abrupt change in load. To avoid this, lower the continuous
running level. Lowering it too low, however, might cause undervoltage that results
from voltage drop due to a control delay.
Before you change the continuous running level, make sure that the continuous
running control will be performed properly, by considering the fluctuations of the
load and the input voltage.
6.3 Details of Function Codes
α
40 HP or above
230 V class series 10 V
460 V class series 20 V
575 V class series 28V
6-65