Siemens SINAMICS S120, Function Manual

Page: 267 / 1094

Vector control
5.16 Fast magnetization for induction motors
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
267
5.16 Fast magnetization for induction motors
For crane applications, frequently a frequency converter is switched alternately to different
motors. After being switched to a different motor, a new data set must be loaded in the
frequency converter and the motor magnetized. This can result in excessive waiting times
which can be significantly reduced by means of quick magnetization.
Features
● Fast magnetization is used for induction motors in vector control.
● Fast flux build-up through injection of a field-generating current at the current limit,
resulting in a significant reduction in magnetizing time.
● The "flying restart" function continues working with parameter p0346 (magnetization
time).
● Magnetization is not dependent on a brake configuration (p1215) as it is with SERVO
drives.
Commissioning
Parameter p1401.6 = 1 (flux control configuration) must be set to activate quick
magnetization.
This setting initiates the following sequence during motor starting:
● The maximum excitation build-up current of the induction motor (in reference to the
permitted rated power module current (r0207[0])) is set with parameter p0644 ("Current
limit excitation build-up induction motor").
● The field-generating current setpoint jumps to the value parameterized in p0644 or the
maximum of I
max
= 0.9 · r0067 (upper limit field-generating current setpoint).
● The flux increases as fast as physically possible with the specified current.
● The flux setpoint r0083 is made to follow accordingly.
● As soon as the flux threshold value programmed in p1573 is reached (min. 10% and max.
200%, factory setting 100%), excitation is ended and the speed setpoint is enabled. The
flux threshold value must not be set too low for a large load because the torque-
producing current is limited during magnetization.
Note
The flux threshold value set in parameter p1573 is effective only if the actual flux during
magnetization reaches the value programmed in p1573 before the time set in p0346.
● The flux is increased further until the flux setpoint in p1570 has been reached.
● The field-producing current setpoint is reduced by means of a flux controller with P gain
(p1590) and the parameterized smoothing factor (p1616).