Danfoss VLT AQUA FC 200 Series Programming Manual page 222

2 Parameter Description
25-55 Alternate if Load < 50%
Option:
2
[0] Disabled
[1] * Enabled
NB!
Only valid if par.25-50
25-56 Staging Mode at Alternation
Option:
[0] * Slow
[1] Quick
Illustration 2.7: Slow Configuration
222
Function:
If Alternation If Capacity <50% is enabled, the pump alternation can only occurs if the capacity is
equal to or below 50%. The capacity calculation is the ratio of running pumps (including the variable
speed pump) to the total number of available pumps (including variable speed pump, but not those
interlocked).
N RUNNING
Capacity
=
N TOTAL
For the Basic Cascade Controller all pumps are equal size.
The lead pump alternation will take place at any pump capacity.
The lead pump function will be alternated only if the numbers of pumps running are providing less
than 50% of total pump capacity.
Lead Pump Alternation
is different from
Function:
This parameter is only active if the option selected in
Off
from [0]
Two types of staging and destaging of pumps are possible. Slow transfer makes staging and de-
staging smooth. Quick Transfer makes staging and destaging as fast as possible; the variable speed
pump is just cut out (coasted).
Slow [0]: At alternation, the variable speed pump is ramped up to maximum speed and then ramped
down to a stand still.
Quick
[1]: At alternation, the variable speed pump is ramped up to maximum speed and then coas-
ted to stand still.
The below examples show Alternation in both Quick and Slow configurations.
MG.20.O4.02 - VLT
®
VLT AQUA Drive Programming Guide
× 100 %
Off
[0].
Lead Pump Alternation
®
is a registered Danfoss trademark
, par. 25-50, is different