Technical information

NOTE
This parameter is only active when 1-10 Motor Construction
has the value PM, non-salient SPM [1] (Permanent Magnet
Motor).
Stator resistance and d-axis Inductance values are
normally, for asynchronous motors, described in technical
specifications as between line and common (starpoint). For
Permanent magnet motors they are typically described in
technical specifications as between Line-Line. PM motors
are typically built for star connection.
1-30 Stator Resistance
(Rs)
(Line to common)
This parameter gives stator winding
resistance(Rs) Similar to Asynchronous
Motor Stator resistance. The Stator
resistance is defined for line to common
measurement. That means for line-line
data (Where stator resistance is measured
between any two lines you need to divide
it with 2).
1-37 d-axis
Inductance (Ld)
(Line to common)
This parameter gives direct axis
inductance of the PM motor. The d-axis
inductance is defined for phase to
common measurement. That means for
line-line data (Where stator resistance is
measured between any two lines you
need to divide it with 2
1-40 Back EMF at
1000 RPM
RMS (Line to Line
Value )
This parameter gives back emf across
stator terminal of PM Motor at 1000rpm
mechanical speed specifically. It is defined
between line to line and expressed in
RMS Value
NOTE
Motor manufacturers provide values for Stator resistance
(1-30 Stator Resistance (Rs)) and d-axis Inductance (1-37 d-
axis Inductance (Ld)) in technical specifications as between
line and common (starpoint) or between Line-Line. There is
no general standard. The different setups of Stator
Winding Resistance and Induction are shown in
Illustration 3.3. Danfoss inverters always require the line to
common value. The back emf of PM motor is defined as
`Induced emf developed across any of two phases of stator
winding of free running Motor'. Danfoss inverters always
require the Line to Line RMS value measured at 1000 rpm,
mechanical speed of rotation. This is shown in
Illustration 3.4)
Line to common (starpoint)
Line to line values
Rs and Ld
Rs and Ld
130BC008.11
Illustration 3.3 Motor parameters are provided in different
formats. Danfoss frequency converters always require the line to
common value.
Permanent magnet motors
130BC009.10
Line to Line Back
Emf in RMS Value
at 1000 rpm
Speed (mech)
Illustration 3.4 Machine parameter definitions of Back Emf of
permanent magnet motors
1-39 Motor Poles
Range: Function:
Size
related*
[2 -
100 ]
Enter the number of motor poles.
Poles ~n
n
@ 50Hz ~n
n
@60Hz
2 2700 - 2880 3250 - 3460
4 1350 - 1450 1625 - 1730
6 700 - 960 840 - 1153
The table shows the number of poles for
normal speed ranges of various motor types.
Define motors designed for other frequencies
separately. The motor pole value is always an
even number, because it refers to the total
number of poles, not pairs of poles. The
frequency converter creates the initial setting
of 1-39 Motor Poles based on 1-23 Motor
Frequency Motor Frequency and 1-25 Motor
Nominal Speed Motor Nominal Speed.
This parameter cannot be adjusted while the
motor is running.
1-40 Back EMF at 1000 RPM
Range: Function:
Size related* [ 10. - 9000
V]
Set the nominal back EMF for the
motor when running at 1000 RPM.
This parameter is only active when
1-10 Motor Construction is set to PM
motor [1] (Permanent Magnet Motor).
Parameter Description
VLT
®
HVAC Drive Programming Guide
MG11CD02 - VLT
®
is a registered Danfoss trademark 41
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