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
ηSTAGE% =
ηLOW
ηHIGH
× 100 %
to 100%, where n
LOW
is Motor Speed Low Limit
and n
HIGH
is Motor Speed High Limit.
130BA367.10
3
5
0 1
Seconds
Variable speed
pump
Fixed speed
pump
Motor speed
high limit
Destaging
speed
Motor speed
low limit
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:
ηSTAGE = ηHIGH
ηSTAGE%
100
where n
HIGH
is Motor Speed High Limit and n
STAGE100%
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:
25-45 Staging Speed [Hz]
Option:
Function:
ηSTAGE = ηHIGH
ηSTAGE%
100
where n
HIGH
is Motor Speed
High Limit and n
STAGE100%
is the value of Staging
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:
ηDESTAGE = ηHIGH
ηDESTAGE%
100
where n
HIGH
is Motor
Speed High Limit and n
DESTAGE100%
is the value of
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:
ηDESTAGE = ηHIGH
ηDESTAGE%
100
where n
HIGH
is Motor Speed High Limit and n
DESTAGE100%
is the value of Destaging Threshold.
Illustration 6.36
Parameter Descriptions
Operating Instructions VLT
®
CDS302 and CDS303
MG34M302 - VLT
®
is a registered Danfoss trademark/Commercial Compressor
113
6
6
