Danfoss VLT FC 102 Programming Manual page 59

Parameter Descriptions
1-37 d-axis Inductance (Ld)
Range: Function:
NOTICE
Size [0.000 -
related 1000.000 mH]
*
This parameter is only active
when parameter 1-10 Motor
Construction is set to [1] PM,
non-salient SPM.
Enter the value of the d-axis
inductance. Obtain the value from
the PM motor datasheet.
For asynchronous motor, stator resistance, and d-axis
inductance values are normally described in technical
specifications as between line and common (startpoint).
For PM motors, they are typically described in technical
specifications as between line-line. PM motors are typically
built for star connection.
Parameter 1-30 Stator This parameter gives stator winding
Resistance (Rs) resistance (R
(line to common). motor stator resistance. The stator
resistance is defined for line-to-
common measurement. For line-line
data, where stator resistance is
measured between any 2 lines, divide
by 2.
Parameter 1-37 d-axis This parameter gives direct axis
Inductance (Ld) inductance of the PM motor. The d-
(line to common). axis inductance is defined for phase-
to-common measurement. For line-
line data, where stator resistance is
measured between any 2 lines, divide
by 2.
Parameter 1-40 Back EMF This parameter gives back EMF across
at 1000 RPM stator terminal of PM motor at 1000
RMS (line to line value). RPM mechanical speed specifically. It
is defined between line-to-line and
expressed in RMS value.
Table 3.6 Parameters Related to PM Motors
M0010001
Programming Guide
) similar to asynchronous
s
Danfoss A/S © 10/2019 All rights reserved.
NOTICE
Motor manufacturers provide values for stator resistance
(parameter 1-30 Stator Resistance (Rs)) and d-axis
inductance (parameter 1-37 d-axis Inductance (Ld)) in
technical specifications as between line and common
(startpoint) or line between line. There is no general
standard. The different set-ups of stator winding
resistance and induction are shown in Illustration 3.6.
Danfoss frequency converters always require the line-to-
common value. The back EMF of a PM motor is defined
as induced EMF developed across any of 2 phases of
stator winding of a free-running motor. Danfoss
frequency converters always require the line-to-line RMS
value measured at 1000 RPM, mechanical speed of
rotation. This is shown in Illustration 3.7.
Line to common (starpoint)
Rs and Ld
Illustration 3.6 Stator Winding Set-ups
Permanent magnet motors
Line-to-line back
EMF in RMS value
at 1000 RPM
speed (mech)
Illustration 3.7 Machine Parameter Definitions of Back EMF of
PM Motors
1-38 q-axis Inductance (Lq)
Range: Function:
NOTICE
Size [0.000 - 1000
related mH]
*
This parameter cannot be
adjusted while the motor is
running.
Set the value of the q-axis
inductance. See the motor
datasheet.
Line-to-line values
Rs and Ld
57
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