25-56 Staging Mode at Alternation
Option: Function:
This parameter is only active if the
option selected in
parameter 25-50 Lead Pump
Alternation is dierent from [0] O.
2 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
standstill.
[1] Quick At alternation, the variable-speed
pump is ramped up to maximum
speed and then coasted to
standstill.
Illustration 3.87 is an example of the slow transfer-staging.
The variable-speed pump (top graph) and 1 xed speed
pump (bottom graph) run before the staging command.
When the [0] Slow transfer command is activated, an
alternation is carried out by ramping the variable- speed
pump to parameter 4-13 Motor Speed High Limit [RPM] or
parameter 4-14 Motor Speed High Limit [Hz], and then
decelerated to zero speed. After a delay before starting
next pump (parameter 25-58 Run Next Pump Delay), the
next lead pump (middle graph) is accelerated and another
original lead pump (top graph) is added after the delay
before running on mains (parameter 25-59 Run on Mains
Delay) as a xed 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 3.87 Staging Mode at Alternation
25-58 Run Next Pump Delay
Range: Function:
0.1 s* [0.1 - 5 s] This parameter is only active if the
option selected in
parameter 25-50 Lead Pump
Alternation is dierent from [0] O.
This parameter sets the time
between stopping the old variable-
speed pump and starting another
pump as a new variable-speed
pump. Refer to
parameter 25-56 Staging Mode at
Alternation for description of
staging and alternation.
25-59 Run on Mains Delay
Range: Function:
0.5 s* [ par. 25-58 -
5 s]
This parameter is only active if the
option selected in
parameter 25-50 Lead Pump
Alternation is dierent from [0] O.
This parameter sets the time
between stopping the old variable
speed pump and starting this
pump as a new xed speed pump.
Refer to Illustration 3.87 for
description of staging and
alternation.
Parameter Descriptions Programming Guide
M0010001 Danfoss A/S © 10/2019 All rights reserved. 245
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