Vector control
5.2 Vector control without encoder (SLVC)
Drive functions
212 Function Manual, 11/2017, 6SL3097-4AB00-0BP5
In the closed-loop controlled mode, for passive loads, induction motors can be operated
under steady-state conditions down to 0 Hz (standstill) without changing over into the open-
loop controlled mode.
Make the following settings for this:
1. Set p0500 = 2 (technological application = passive loads for encoderless control to f = 0).
2. Set p0578 = 1 (calculate technology-dependent parameters).
The following parameters are then set automatically:
– p1574 = 2 V for induction motors
– p1574 = 4 V for separately excited synchronous motors
– p1750.2 = 1, closed-loop operation down to 0 Hz for passive loads
– p1802 = 4 SVM/FLB without overcontrol
– p1803 = 106% (factory setting)
As a consequence, the "Passive load" function is automatically activated.
Note
If p0500 is parameterized when commissioning the motor, the calculation is carried out
automatically via p034
0 and p3900. p0578is is then set automatically.
Closed-loop control without changeover between closed-loop and open-loop speed control is
restricted to applications with passive load:
A passive load only has a reactive effect on the drive torque of the driving motor at the
starting point, e.g. high inertia masses, pumps, fans, centrifuges, extruders, travel drives, or
horizontal conveyors.
Standstill without a holding current is possible for as long as required. Then, at standstill,
only the magnetizing current is impressed in the motor.
Note
Generator operation
Steady
-state generator operation at frequencies close to 0 Hz is not permissible in this
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