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Vacon
Page 51
Pump control with autochange
9. 25
Frequency drop delay after starting an auxiliary drive
9. 26
Frequency increase delay after stopping an auxiliary drive
If the speed of auxiliary drive increases slowly (e.g. soft starter control) then a
delay (par. 9.25) between auxiliary drive start and the frequency drop of the vari-
able speed drive will make the control smoother.
Also if the speed of the auxiliary drives decreases slowly (soft starter control)
then with parameter 9.26 a delay between auxiliary drive stop and the frequency
increase of the variable speed drive can be programmed. See figure 6-32.
If either value of parameters 9.25 and 9.26 is maximum (300,0 s) then there is
no frequency drop nor increase.
Figure 6-32
Frequency drop and increase delays
vuorot4.fh3
Output frequency
Time
Start freq. of aux drive + 1 Hz
Start delay of
aux. drive (par. 9.10)
Frequency drop
delay (par. 9.25)
Aux. drive
control
Aux. drive
speed
Stop delay of
aux. drive (par. 9.11)
Frequency increase
delay (par. 9.26)
Stop freq. of aux drive - 1 Hz
Aux. drive
speed