The longitudinal end-effect associated with the short primary linear induction motor (LIM) distinguishes it from the rotary induction motor (RIM) insofar as analytical modelling is concerned. The short-primary phenomenon can be considered as a space transient effect, in which longitudinal mmf and flux distributions are described with exponential envelopes having speed dependent 'space constants'. A second approach treats the finite length winding as the superposition of many 'long' windings or space-harmonic components. The two viewpoints are complementary, and comparison to the time-domain/frequency-domain duality of network theory is appropriate. The classical equivalent circuit provides a convenient model for the RIM, but does not account for longitudinal end-effects in LIM's. Two variations of the equivalent circuit can be developed from the end-transient and space-harmonic bases, respectively. It will be shown that both equivalent circuits are useful in determining the dynamic performance of LIM's, either from standstill measurements or from parameter computations. Two representations of the LIM longitudinal end-effect have been discussed. Both were presented in equivalent circuit terms to show that standard RIM circuit parameter formulae, or measured (standstill) LIM parameters may be employed in dynamic performance prediction. The space harmonic model is computationally more complex than the end transient model, but can offer a means of including the effects of discrete conductor placement, half-filled end slots, and unconventional winding geometries.
Space-harmonic and end-transient representations of the linear induction motor
Raumzeiger und Transienten-Endzustandsdarstellung bei Kurzstator-Linear-Asynchronmotoren
Proc. Int. Conf. on Electrical Machines, Part 2 ; Sep ; 473-476
1984
4 Seiten, 8 Bilder, 1 Tabelle, 5 Quellen
Conference paper
English
Analysis of linear induction motors using a simplified space harmonic technique
Tema Archive | 1986
|A reconfigurable induction motor drive with selective harmonic cancellation
British Library Conference Proceedings | 2006
|Linear induction motor driving overhead crane
Engineering Index Backfile | 1966