Danfoss VLT HVAC Series Programming Manual page 234

3 Parameter Description
3
[0] * Disabled
[1] Enabled
22-83 Speed at No-Flow [RPM]
Range:
300. RPM* [0 - par. 22-85 RPM]
22-84 Speed at No-Flow [Hz]
Range:
50.0 Hz* [0.0 - par. 22-86 Hz]
3-210
Example 2:
Speed at System Design Working Point is not known: Where the Speed at System Design Working
Point is unknown, another reference point on the control curve needs to be determined by means
of the data sheet. By looking at the curve for the rated speed and plotting the design pressure
(H , Point C), the flow at that pressure Q
DESIGN
design flow (Q , Point D), the pressure H
DESIGN
points on the pump curve, along with H
to calculate the reference point B and thus to plot the control curve that will also include the system
design working point A.
Disabled [0]
: Work Point Calculation not active. To be used if speed at design point is known (see
table above).
Enabled [1] : Work Point Calculation is active. Enabling this parameter allows the calculation of the
unknown System Design Working Point at 50/60 Hz speed, from the input data set in par.
Speed at No-Flow [RPM]
22-83 par.22-84
Speed Pressure at Rated Speed
, par.22-88
Rated Speed
.
Function:
Resolution 1 RPM.
The speed of the motor at which the flow is zero and the minimum pressure H
be entered here in RPM. Alternatively, the speed in Hz can be entered in par.22-84
Flow [Hz]
. If it has been decided to use RPM in par.0-02
at Design Point [RPM]
should also be used. Closing the valves and reducing the speed until minimum
pressure H is achieved will determine this value.
MIN
Function:
Resolution 0.033 Hz.
The speed of the motor at which flow has effectively stopped and minimum pressure H
should be entered here in Hz. Alternatively, the speed in RPM can be entered in par.22-83
at No-Flow [RPM]
. If it has been decided to use Hz in par.0-02
Speed at Design Point [Hz]
22-86 should also be used. Closing the valves and reducing the speed
until minimum pressure H is achieved will determine this value.
MIN
MG.11.C6.22 - VLT ® is a registered Danfoss trademark
VLT ® HVAC Drive Programming Guide
can be determined. Similarly, by plotting the
RATED
at that flow can be determined. Knowing these two
D
described above, allows the adjustable frequency drive
MIN
Speed at No-Flow [Hz]
, par.22-87
Flow at Design Point
, par.22-89 and par.22-90
Motor Speed Unit
, then par.22-85
Motor Speed Unit
Pressure at No-Flow
Flow at
is achieved should
MIN
Speed at No-
Speed
is achieved
MIN
Speed
, then par.