Fuji Electric FRENIC-MEGA, Instruction Manual

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5-56
Ch
ap
. 5
FUNCTION C
O
DES
F codes
Factory default:
By factory default, H13 is set to the value suitable for the standard motor (see Table A in Section 5.1
"Function Code Tables"). Basically, it is not necessary to change H13 data. However, if the long restart time causes the flow
rate of the pump to overly decrease or causes any other problem, you might as well reduce the setting to about a half of the
default value. In such a case, make sure that no alarm occurs.
Function code H13 (Restart mode after momentary power failure -- Restart time) also applies to the switching
operation between line and inverter (refer to the descriptions of E01 through E07).
„ 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
t
he 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.
Power supply voltage
α
40 HP or below 50 HP or above
230 V series 5 V 10 V
460 V series 10 V 20 V