zig-zag flux and stray losses? 1

[electricpete]

What is zig-zag flux? And how does it contribute to stray losses in an induction motor?

 

[Mohsen1]

zig-zag flux in Induction machine is a harmonic flux as obtained from a finite element analysis due to Inverter-fed operation , more details available in site

http://www.ekc.kth.se/eme/eme_eng.html

http://www.ekc.kth.se/eme/fem_desc1.html

 

[electricpete]

thanks. The original context where I heard this term had nothing to do with inverter-fed drives.

Someone stated that if care is not taken during coil removal for rewound of random-wound machines, the stator slot teeth can be deformed or damaged resulting in and increase in zig-zag flux patterns and associated increase in stray loss.

Based on your the info you provided, I believe that zig-zag flux must be the fringing flux (non-radial flux) which created when a rotor bar sits on top of a stator tooth... flux must go tangentially to get to the rotor iron.

I can see how this would perhaps represent a harmonic leakage reactance. I'm not sure how it would contribute a stray losses.

 

[electricpete]

It must be the high frequency content of the flux (due to slotting) that causes increase in core losses and perhaps stray losses.

 

[jbartos]

Suggestion: Visit

http://home.c2i.net/owand/fld12.htm

http://www.ladwp.com/energyadvisor/EA_47.html

(The zig-zag winding is a design that places half of the turns of each phase of the secondary around two of the legs of the transformer core (in the standard design, all turns for a given phase go around just one core leg). This technique causes cancellation of the magnetic flux established by triplen harmonic currents, so little or none is transferred to the primary windings.)

http://ee.its.tudelft.nl/epp/ReMain_Public_00.htm

(Deleroi W; High Harmonic Fundamental Current Modulation Caused By Zig-Zag Leakage Flux Pulsation. In: ICEM 98 Proceedings. (Istanbul, Turkije, 9/2/98), Middle East Technical University, Ankara, 1998, P. 193-199. ISBN: 975-429-125.)