Siemens SINAMICS S120 Function Manual page 132

Servo control
5.11 Increased stall power at the voltage limit
Specifics for induction motors
For induction motors, the higher stall power (p1402.6 = 1) is automatically preassigned when
recommissioning. At the same time, the motor stall power limiting remains deactivated
(p1402.3 = 0), so that the new control is only active in the generator mode.
Note
When motoring (accelerating, machining), the new closed-loop control can result in increased
motor losses for some motors; this means that even in spite of a higher active power drawn, the
torque at the motor shaft is not increased.
A combination of the higher stall power (p1402.6 = 1) with the activated stall power limiting
motoring (p1402.3 = 1) is only recommended if shorter acceleration times can be achieved than
with p1402.3 = 0.
As a result of the new voltage management, when an overload condition is demanded in the
stall power range, if required, additional field weakening can be implemented in order to set the
operating point with the maximum power.
In encoderless operation, in the high field weakening range, this additional field weakening can
destabilize the motor model. Increasing the speed actual value smoothing time without encoder
(p1451, e.g. to 15 ms) or reducing the speed controller P gain in encoderless operation (p1470)
can counteract this effect.
Special situation, synchronous motors
For synchronous motors, the higher stall power (p1402.6 = 1) is not automatically preassigned.
An increased motor power with p1402.6 = 1 can only be expected in the stall power range if the
motor can handle the short-circuit current (p0640 > r0331). The power increase is especially
high if the motor has a reluctance torque (p0327 > 90°, p0328 > 0). The increased power
applies both for motors as well as when generating. p1402.3 is not relevant for synchronous
motors.
Overview of important parameters (see SINAMICS S120/S150 List Manual)
● p0326[0...n]
● r0331[0...n]
● p0388[0...n]
● p0640[0...n]
● p1402[0...n]
● p1520[0...n]
● p1521[0...n]
● p1531[0...n]
● r1549[0...1]
130
Motor stall torque correction factor
Actual motor magnetizing current / short-circuit current
Motor stall torque correction factor for p1402.6 = 1
Current limit
Current control and motor model configuration
CO: Torque limit upper/motoring
CO: Torque limit lower/regenerative
Power limit regenerative
CO: Actual stall power value
Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Drive functions