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Three-phase windings with "q" < 1

Three-phase windings with "q" < 1

Three-phase windings with "q" < 1

(OP)

Three-phase motors with q > = 1 ("q" is the number of slots per pole and phase) are most common in practice, but there are motors with q < 1, also. Is very difficult to find some literature on these windings (the application, the rules for formation, calculation of the base winding coefficient, a diagrams of the internal connection, etc).
Does anyone have more information on these windings and, perhaps, an example to illustrate?
Zlatkodo

RE: Three-phase windings with "q" < 1


zlatkodo:

q figures of < 1 are possible for three-phase stator windings. The German term for this type of stator winding is "Zahnwicklung". Application is for servo motors with permanent magnet rotors. Go to

www.sew-eurodrive.de/download/pdf/11322802.pdf

for more information. Pages 17 and 18 give you an example for a q = 0.5 application (6 poles, 9 slots). I'm sure there is an English leaflet available as the company in question has some subsidiaries in the U.S..

A collegue of mine built a hydro generator model with 50 permanent poles and 60 slots, i.e. q = 0.4 slots per pole and phase (see attachment). With a crank, some switches, some 40 Watt light bulbs and a motor it is possible to demonstrate three-phase and single-phase service (the latter can be felt as pulsations on the crank).

Wolf
www.hydropower-consult.com  

RE: Three-phase windings with "q" < 1

(OP)
Hi, Wolf,
I know for these motors with Neodymium-Iron-Boron  permanent magnets Nd-Fe-B, called PMSMs (permanent magnet synchronous motors ) but I am more interested in the classical asynchronous three-phase motors with q < 1, which also exist.
 One interesting example is attached.
Zlatkodo

RE: Three-phase windings with "q" < 1


Zlatko:

Sorry, no clue. The book in question has not been published by the famous Springer Verlag. Springer always prints the page numbers at the top, not at the bottom of page. Also, I've noticed that Fig. 328 is on page 371. This seems to be sort of a "picture book" with little text. The letters printed look quite old-fashioned, possibly pre-war. I'll try to find out more, but give me some time.

Wolf  

RE: Three-phase windings with "q" < 1

(OP)

Does anyone have experience with these windings, with q < 1?
Wolf,
You're right. Mentioned "Katechismus" is very, very old book, from  1944 year.
Zlatkodo

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