Note About The Electronic Motor Model; V/F Control For Diagnostics - Siemens SINAMICS S120 Function Manual

3.8

Note about the electronic motor model

A model change takes place within the speed range p1752*(100%-p1756) and p1752. With
induction motors with encoder, the torque image is more accurate in higher speed ranges;
the effect of the rotor resistance and the saturation of the main field inductance are
corrected. With synchronous motors with encoder, the commutation angle is monitored. If
the kT estimator has been activated, the torque image for synchronous motors is more
accurate too.
3.9

V/f control for diagnostics

Description
With V/f control, the motor is operated with an open control loop and does require speed
control or actual current sensing, for example. Operation is possible with a small amount of
motor data.
V/f control can be used to check the following:
● Motor Module
● Power cable between Motor Module <–> motor
● Motor
● DRIVE-CLiQ cable between Motor Module <–> motor
● Encoder and actual encoder value
The following motors can be operated with V/f control:
● Induction motors
● Synchronous motors
Drive functions
Function Manual, (FH1), 10/2008, 6SL3097-2AB00-0BP5
CAUTION
V/f control must only be used as a diagnostic function (e.g. to check that the motor
encoder is functioning correctly).
Note
In V/f mode, the calculated actual speed value is always displayed in r0063. The speed of
the encoder (if installed) is displayed in r0061. If an encoder is not installed, r0061
displays "0".
Note
The operation of synchronous motors with V/f control is allowed only at up to 25 % of the
rated motor speed.
3.8 Note about the electronic motor model
Servo control
87