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Synchronism | 07 Nov 2013 | |


Table of Contents

  1. Concentricity
  2. Cogging
  3. THD

All parameters described below have an influence to the synchron run of a motor in a servo system. Additionally the influence of the Feedback system must be observed.


EN 42955 N (normal) or R (reduced) describes the planeness and concentricity of axis to flange. This is independent from the manufacturing tolerances of axis, flange and bearings (see Shaft extension and flange run-out).

AKM: specified with EN 42955 N, R is in process as guaranteed option. 98% of the production ar already R.


Cogging describes the varying torque behaviour caused by changing magnetical flow from rotor to stator. Servo amplifiers S300 and S700 have an intelligent function for Cogging Suppression.

AKM: nominal <2% (<+/- 1%), typical with AKM4...7 is <1,5% (+/- 0,75%). Motors of other manufacturers have typical values of  <+/-2% or absolute <4%


THD (Total Harmonic Distortion) describes the deviation from theoretic sine wave and the harmonics, caused by unequal resistors and inductivities of the windings and by mechanical tolerances in production of stator and rotor.

AKM: nominal <2%, typical with AKM4...7 is <1,5%. Motors of other manufacturers have nominal values of >3%.

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