Santerno DCREG2 Series User Manual page 104

15P0059B3
USER MANUAL
In order to enable this operating mode, the drive starts decreasing the field current when the speed
required increases, so that the back-electromotive force does not exceed the nominal value.
Suppose the motor ratings are the following as far as the field weakening is concerned:
Nominal armature voltage
Nominal field voltage
Nominal field current
Field weakening starting speed 1000 RPM
Min. field current
Max. speed
First, we have to consider that the 220 VDC voltage required for the field exceeds max. 205 VDC that can
be obtained with a field regulator power supply (terminals E1-2) ranging from 200 to 240 VAC, so a
voltage equal or larger than 400 VAC is required for said terminals.
As we stated in the chapter concerning the basic start-up procedure, the RxI resistive drop autotuning
is to be performed by setting par. P001 to 3:RxI. Starting from this value and the value of the rated
armature, the drive will estimate the nominal back-electromotive force (max.) to be adjusted.
The parameters below are to be set, supposing a DCREG.350 is used, with a 15A nominal field current:
P010 (nFdbkMax) = 4000 RPM
9
C010 (IfldNom) =
10
C011 (BaseSpeed) =
RPM)
C012 (VarmNom) = 400V
1 8 .
C016 (IfldNom) =
9
The parameters above are required for the field weakening correct operation and the trend with respect of
the field current reference speed displayed in par.M017 (RefFld) is shown in the figure below.
RefFld
(M017)
C010
( C010  C011)
C010  C016
104/200
400V
220V
9A (with motor at zero speed or with not yet weakened field)
1.8A (with motor at its max. speed)
4000 RPM

100 = 60% (9A with respect to the drive 15A rated current)
1000

100 =25% (1000 RPM of weakening starting with respect to max. 4000
4000
 
. 0 75 100 = 15% (75% of min. 1.8A with respect to 9A rated current)
M007
max
( C011  P010)
= f.c.e.m.
DCREG2
DCREG4
n
P010