Danfoss VLT Programming Guide

(H
DESIGN
, Point C) the flow at that pressure Q
RATED
can be determined. Similarly, by plotting the
design flow (Q
DESIGN
, Point D). the pressure H
D
at that flow can be determined. Knowing these two
points on the pump curve, along with H
MIN
as described above, allows the frequency converter to
calculate the reference point B and thus to plot the control curve which will also include the System
design Working Point A.
[0] * Disabled Disabled [0] : Work Point Calculation not active. To be used if speed at design point is known (see
table above).
[1] Enabled
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. 22-83
Speed at No-Flow [RPM] par. 22-84 Speed at No-Flow [Hz] , par. 22-87 Pressure at No-
Flow Speed
, par. 22-88 Pressure at Rated Speed , par. 22-89 Flow at Design Point and
par. 22-90
Flow at Rated Speed .
22-83 Speed at No-Flow [RPM]
Range: Function:
Application
dependent*
[Application dependant] Resolution 1 RPM.
The speed of the motor at which flow Is zero and minimum pressure H
MIN
is achieved should be
entered here in RPM. Alternatively, the speed in Hz can be entered in par. 22-84
Speed at No-Flow
[Hz]
. If it has been decided to use RPM in par. 0-02 Motor Speed Unit then par. 22-85 Speed at
Design Point [RPM]
should also be used. Closing the valves and reducing the speed until minimum
pressure H
MIN
is achieved will determine this value.
22-84 Speed at No-Flow [Hz]
Range: Function:
Application
dependent*
[Application dependant] Resolution 0.033 Hz.
The speed of the motor at which flow has effectively stopped and minimum pressure H
MIN
is achieved
should be entered here in Hz. Alternatively, the speed in RPM can be entered in par. 22-83
Speed
at No-Flow [RPM]
. If it has been decided to use Hz in par. 0-02 Motor Speed Unit then
par. 22-86
Speed at Design Point [Hz] should also be used. Closing the valves and reducing the
speed until minimum pressure H
MIN
is achieved will determine this value.
22-85 Speed at Design Point [RPM]
Range: Function:
Application
dependent*
[Application dependant] Resolution 1 RPM.
Only visible when par. 22-82
Work Point Calculation is set to Disable . The speed of the motor at
which the System Design Working Point is achieved should be entered here in RPM. Alternatively,
the speed in Hz can be entered in par. 22-86
Speed at Design Point [Hz] . If it has been decided to
use RPM in par. 0-02
Motor Speed Unit then par. 22-83 Speed at No-Flow [RPM] should also be
used.
VLT
®
HVAC Drive Programming Guide 3 Parameter Description
MG.11.C9.02 - VLT
®
is a registered Danfoss trademark 215
3

Danfoss VLT Specifications

General

Frequency	50/60 Hz
Enclosure	IP20, IP21, IP55, IP66
Series	VLT
Control Technique	Flux Vector Control
Output Voltage	0-Vinput
Control Method	Fieldbus
Communication Interface	PROFIBUS, CANopen
Protection Features	Overload, Overvoltage, Undervoltage, Short Circuit, Ground Fault
Cooling Method	Liquid Cooled
Storage Temperature	-25°C to +70°C
Relative Humidity	5-95% non-condensing
Altitude	Up to 1000m (3280ft) without derating, up to 4000m (13120ft) with derating
Operating Temperature	-10°C to +50°C (14°F to 122°F)