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Functions, monitoring and protective functions
9.3 Drive functions
9.3.3
Fast magnetization for induction motors
Description
Fast magnetization for induction motors is used to reduce delay time during magnetization.
Features
● Rapid flux build-up by injecting a field-generating current at the current limit, which
considerably reduces the magnetization time.
● If the "flying restart" function is activated, the excitation build-up time set in p0346 is still
used.
Commissioning
Parameter setting p1401.6 = 1 is necessary to activate fast 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 set in p0644 or the maximum of
Imax = 0.9 x r0067 (high 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 %, max.
200 %, factory setting: 100 %), excitation ceases 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
Influence of the flux threshold value
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 timer set in p0346
runs down.
● The flux is increased further until the flux setpoint in p1570 has been reached.
● The field-producing current setpoint is reduced using a flux controller with P gain (p1590)
and the assigned smoothing factor (p1616).
500
Converter cabinet units
Operating Instructions, 11/2017, A5E36652151A
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