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25-40 Ramp Down Delay
Range:
Function:
10.0 s*
[0.0 - 120.0 s]
When adding a fixed speed pump controlled by a soft starter, it is possible to delay the ramp down
of the lead pump until a preset time after the start of the fixed speed pump to eliminate pressure
surges or water hammer in the system.
Only to be used if
Soft Starter
[1] is selected in par.25-02
25-41 Ramp Up Delay
Range:
Function:
2.0 s*
[0.0 - 12.0 s]
When removing a fixed speed pump controlled by a soft starter, it is possible to delay the ramp up
of the lead pump until a preset time after the stopping of the fixed speed pump to eliminate pressure
surges or water hammer in the system.
Only to be used if
Soft Starter
[1] is selected in par.25-02
25-42 Staging Threshold
Range:
Function:
0 %*
[0 - 100 %]
When adding a fixed speed pump, in order to prevent an overshoot of pressure, the variable speed
pump ramps down to a lower speed. When the variable speed pump reaches the “Staging Speed”
the fixed speed pump is staged on. The Staging Threshold is used to calculate the speed of the
variable speed pump when the “cut-in point” of the fixed speed pump occurs. The calculation of the
Staging Threshold is the ratio of par.4-11
, expressed in percent.
Staging Threshold must range from
STAGE
%
=
LOW
HIGH
× 100 %
to 100%, where n
LOW
is Motor Speed Low Limit and n
HIGH
is Motor Speed High Limit.
NB!
If the set-point is reached after staging before the variable speed pump reaches its minimum speed - the system will enter the state closed loop as
soon as the feedback pressure is crossing the set-point.
2 Parameter Description
VLT
®
AQUA Drive Programming Guide
218
MG.20.O4.02 - VLT
®
is a registered Danfoss trademark
2