Danfoss VLT Refrigeration Drive FC 103 Programming Manual page 178

Parameter Description
25-45 Staging Speed [Hz]
Option: Function:
Staging speed is calculated with the following
formula:
η
3 3
STAGE
limit and n
threshold.
25-46 Destaging Speed [RPM]
Readout of the below calculated value for destaging speed.
When removing a fixed speed compressor to prevent an
undershoot of pressure, the variable speed compressor ramps up
to a higher speed. When the variable speed compressor reaches
the destaging speed, the fixed speed compressor is destaged.
Destaging speed is calculated based on
parameter 25-43 Destaging Threshold and parameter 4-13 Motor
Speed High Limit [RPM].
Destaging speed is calculated with the following formula:
η
η = η
DESTAGE HIGH
n is the value of the destaging threshold.
DESTAGE100%
Range:
0 RPM
*
25-47 Destaging Speed [Hz]
Readout of the below calculated value for destaging speed.
When removing a fixed speed compressor to prevent an
undershoot of pressure, the variable speed compressor ramps up
to a higher speed. When the variable speed compressor reaches
the destaging speed, the fixed speed compressor is destaged.
Destaging speed is calculated based on
parameter 25-43 Destaging Threshold and parameter 4-14 Motor
Speed High Limit [Hz].
Destaging speed is calculated with the following formula:
η
η = η
DESTAGE HIGH
where n is motor speed high limit and n
HIGH
value of the destaging threshold.
Illustration 3.67 Destaging Speed
Range:
0 Hz
*
176
η
where n is motor speed high
STAGE %
= η
HIGH
HIGH
100
is the value of the staging
STAGE100%
DESTAGE % where n is motor speed high limit and
HIGH
100
Function:
[000 - 30000 RPM]
DESTAGE %
100
DESTAGE100%
Function:
[0 - 6500 Hz]
Danfoss A/S © 05/2016 All rights reserved.
®
VLT Refrigeration Drive FC 103
3.20.6 25-5* Alternation Settings
Parameters for defining the conditions for alternation of
the variable speed pump (lead), if selected as control
strategy.
25-50 Lead Pump Alternation
Option:
[0] Off
*
[1] At staging
[2] At
command
[3] At staging
or
command
is the
Function:
NOTICE
If parameter 25-05 Fixed Lead Compressor
is set to [1] Yes, it is only possible to
select [0] Off.
Lead pump alternation equalizes the use of
pumps by periodically changing the pump that
is speed-controlled. This ensures that pumps
are equally used over time. Alternation
equalizes the usage of pumps by always
selecting the pump with the lowest number of
hours run to stage on next.
No alternation of lead pump function takes
place. It is not possible to set this parameter to
options other than [0] Off if
parameter 25-02 Motor Start is set other than [0]
Direct on Line.
Alternation of the lead pump function takes
place when staging another pump.
Alternation of the lead pump function takes
place at an external command signal or a pre-
programmed event. See
parameter 25-51 Alternation Event for available
options.
Alternation of the variable speed (lead) pump
takes place at staging or according to [2] At
command.
MG16H202