Danfoss VLT CDS302 Operating Instructions Manual page 113

Parameter Descriptions
25-43 Destaging Threshold
Range: Function:
is used to calculate the speed of the variable
speed compressor when the destaging of the
fixed speed compressor occurs. The calculation of
the Destaging Threshold is the ratio of 4-11 Motor
Speed Low Limit [RPM] or 4-12 Motor Speed Low
Limit [Hz] to 4-13 Motor Speed High Limit [RPM] or
4-14 Motor Speed High Limit [Hz] expressed in
percent.
Destaging Threshold must range from
η
LOW
η STAGE % =
η
HIGH
to 100%, where n
and n is Motor Speed High Limit.
HIGH
Motor speed
high limit
Destaging
speed
Motor speed
low limit
0 1
Illustration 6.35
25-44 Staging Speed [RPM]
Option: Function:
0 N/A Readout of the below calculated value for Staging
Speed. When adding a fixed speed compressor, in
order to prevent an overshoot of pressure, the
variable speed compressor ramps down to a lower
speed. When the variable speed compressor reaches
the "Staging Speed" the fixed speed compressor is
staged on. Staging Speed calculation is based on
25-42 Staging Threshold and 4-13 Motor Speed High
Limit [RPM].
Staging Speed is calculated with the following
formula:
η
STAGE %
η STAGE = η HIGH
100
where n is Motor Speed High Limit and n
HIGH
is the value of Staging Threshold.
25-45 Staging Speed [Hz]
Option: Function:
0 N/A Readout of the below calculated value for Staging
Speed When adding a fixed speed compressor, in
order to prevent an overshoot of pressure, the
variable speed compressor ramps down to a lower
speed. When the variable speed compressor reaches
the "Staging Speed" the fixed speed compressor is
staged on. Staging Speed calculation is based on
25-42 Staging Threshold and 4-14 Motor Speed High
Limit [Hz].
Staging Speed is calculated with the following
formula:
MG34M302 - VLT
Operating Instructions VLT
× 100 %
is Motor Speed Low Limit
LOW
Variable speed
pump
Fixed speed
pump
3 5 Seconds
STAGE100%
®
is a registered Danfoss trademark/Commercial Compressor
®
CDS302 and CDS303
25-45 Staging Speed [Hz]
Option: Function:
η
STAGE %
η STAGE = η HIGH
100
High Limit and n
STAGE100%
Threshold.
25-46 Destaging Speed [RPM]
Option: Function:
0 N/A Readout of the below calculated value for Destaging
Speed. When removing a fixed speed compressor, in
order 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
25-43 Destaging Threshold and 4-13 Motor Speed High
Limit [RPM].
Destaging Speed is calculated with the following
formula:
η
DESTAGE %
η DESTAGE = η HIGH
100
Speed High Limit and n
Destaging Threshold.
25-47 Destaging Speed [Hz]
Option: Function:
Readout of the below calculated value for Destaging
Speed. When removing a fixed speed compressor, in
order 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 25-43 Destaging
Threshold and 4-14 Motor Speed High Limit [Hz]
Destaging Speed is calculated with the following
formula:
η
DESTAGE %
η DESTAGE = η HIGH
100
where n is Motor Speed High Limit and n
HIGH
is the value of Destaging Threshold.
Illustration 6.36
where n is Motor Speed
HIGH
is the value of Staging
where n is Motor
HIGH
is the value of
DESTAGE100%
DESTAGE100%
113
6 6