Siemens SIMOVERT MASTERDRIVES Manual page 233

05.2006
Manual optimization
Siemens AG 6SE7087-6QX70 (Version AG)
SIMOVERT MASTERDRIVES
When the parameters relevant to field weakening have been set via
automatic parameterization, they do not need to be adjusted again for
most applications. The default settings ensure that the motor enters the
field weakening range at speeds above rated value. The terminal
voltage is kept constant under no load in the field weakening range.
The maximum torque decreases in proportion to 1/n, the maximum
output remains constant.
The settings can be optimized manually for special applications. If, for
example, the required maximum torque is lower than the torque
obtained with the default setting, the speed at which field weakening
commences can be raised to reduce the thermal loading of the motor
by the field weakening current.
How to optimize the settings:
1. Determine the speed at which field weakening commences on the
basis of the desired torque value and the limit characteristics field
from the Engineering Information:
100
90
80
70
60
50
40
30
20
10
0
0 500 1000
e.g. 1FT6086-8AF71, 27.5 Nm, 2900 rev/min
Enter the calculated field weakening activation speed in P299.
Compendium Motion Control
1FT6086 - 8AF71
S3 - 25%
S3 - 40%
S3 - 60%
S1 (100K)
S1 (60K)
1500 2000 2500
Speed [min-1]
Functions
Field
weakening
activation point
3000 3500 4000
7-67
4500