25-56 Staging Mode at Alternation
Option:
Function:
This parameter is only active if the option selected in
is different from
Off
[0].
Two types of staging and destaging of pumps are
possible. Slow transfer makes staging and destaging
smooth. Quick Transfer makes staging and destaging
as fast as possible; the variable speed pump is just cut
out (coasted).
[0]
*
Slow At alternation, the variable speed pump is ramped up
to maximum speed and then ramped down to a stand
still.
[1]
Quick At alternation, the variable speed pump is ramped up
to maximum speed and then coasted to stand still.
The variable speed pump (top graph) and one fixed speed
pump (bottom graph) are running before the staging
command, see
. When the
Slow
[0] transfer
command is activated, an alternation is carried out by
ramping the variable speed pump to
or
4-14 Motor Speed High Limit [Hz]
, and then
decelerated to zero speed. After a “Delay Before Starting
Next Pump” (
) the next lead pump
(middle graph) is accelerated and another original lead
pump (top graph) is added after the “Delay Before Running
On Mains” (
) as a fixed speed pump.
The next lead pump (middle graph) is decelerated to Motor
Speed Low Limit and then allowed to vary speed to maintain
system pressure.
130BA369.10
Seconds
Variable speed
pump
Motor speed
high limit
Destaging
speed
Motor speed
low limit
Fixed speed
pump
Motor speed
low limit
Staging
speed
Motor speed
high limit
Seconds
Fixed speed
pump
Motor speed
high limit
Destaging
speed
Motor speed
low limit
Seconds
Delay before
running
on mains
Variable speed
pump
Delay
before starting
next pump
Staging
command
Illustration 3.7 Slow Transfer Staging
25-58 Run Next Pump Delay
Range:
Function:
0.1 s
*
[0.1 - 5.0
s]
This parameter is only active if the option
selected in
, is
different from
Off
[0].
This parameter sets the time between stopping
the old variable speed pump and starting
another pump as a new variable speed pump.
Refer to
25-56 Staging Mode at Alternation
, the
illustration for description of staging and
alternation.
25-59 Run on Mains Delay
Range:
Function:
0.5 s
*
[par. 25-58
- 5.0 s]
This parameter is only active if the option
selected in
, is
different from
Off
[0].
This parameter sets the time between
stopping the old variable speed pump and
starting this pump as a new fixed speed pump.
Refer to
25-56 Staging Mode at Alternation
, the
illustration for description of staging and
alternation.
Parameter Description
VLT
®
HVAC Drive Programming Guide
MG.11.CB.02 - VLT
®
is a registered Danfoss trademark
175
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