Siemens 420 manual 21.1.4 V/f resonance damping, Effect of V/f resonance damping

Issue 07/04 3 Functions

3.21.1.4V/f resonance damping

Parameter range:	P1338
Warnings	-
Faults	-
Function chart number:	-

For variable-speed drives, resonance effects can occur in the upper frequency range (> 20 Hz). These resonance effects result in an increased noise level and also can damage / destroy the mechanical system. These resonance effects can occur for:

Geared motors Reluctance motors

Large motors

(low stator resistance → poor electrical damping)

Contrary to the "skip frequency" function (refer to Section 3.12.1 and parameters P1091 to P1094), where the resonance frequency is passed through as quickly as possible, for the V/f resonance damping (parameter P1338), the resonance effects are dampened from a control-related perspective. The advantage of this function is that by using this active damping, operation is possible in the resonance range.

The V/f resonance damping is activated and adjusted using parameter P1338. This parameter represents a gain factor that is a measure for the damping of the resonance frequency. The following oscillogram (refer to Fig. 3-63) indicates the effect of the resonance damping function using as an example a reluctance motor with gearbox. The phase output currents are displayed for an output frequency of 45 Hz.

Without V/f resonance damping (P1338 = 0) V/f resonance damping active (P1338 = 1)

Fig. 3-63 Effect of V/f resonance damping

MICROMASTER 420	Operating Instructions
6SE6400-5AA00-0BP0	149