Convention for winding direction of SMPS transformers?....what is "clockwise"?

[treez]

Supposing i have a horizontal E42/21/15 bobbin as on page 5 of the following....

https://ferroxcube.home.pl/prod/assets/e422115.pdf

Assume its 10 pins number like an IC
Often you get winding specs annotated by saying "all windings wound clockwise round the former".
What does this mean?
Supposing you have a primary connected from start pin 3 to pin 4
And a secondary connected from start pin 9 to pin 10.
Do you take "clockwise" as being as if you are looking at the row of primary or secondary pins depending on which coil you are winding?.....or do you take it that "clockwise" always means looking at the "Pins 1 to 5" side?
Do winding companys have any convention here?

Wouldnt it just be better to give a coil cross section diagram and show which end is the "dot" end?

 

[betwixt]

There is a difference between the 'dot' end and the direction of the winding. It means all the windings follow the same axis of rotation around the core rather than some being the other way around in a weave pattern. To reverse the polarity of signal on a winding you can use the 'dot' to connect the opposite end of a winding, the clockwise reference is the actual direction the wire traverses around the bobbin.

Brian.

 

[treez]

the clockwise reference is the actual direction the wire traverses around the bobbin.

Thanks, i tend to agree, but it seems misleading, as the clockwise direction depends on which way round you hold the bobbin.

It means all the windings follow the same axis of rotation around the core rather than some being the other way around in a weave pattern.

...Thanks, this is the description that i believe is required...rather than saying "all windings clockwise".

What do winders prefer?
I always specify on the "pin and coil" diagram where the dots are, and specify on the windings cross section diagram which end the dots are....this way there's no need to make any reference to winding rotational direction...the winder can just work it through themselves. But i am wondering how they prefer to have the information presented?

 

[betwixt]

Functionally it makes absolutely no difference and from a construction point of view I doubt it matters whether the winding machine rotates one way or the other. I think the wording in intended to mean all winding are in the same direction rather than specifically clockwise or anti-clockwise.

Brian.

 

[Easy peasy]

generally when winding - the longtiudinal axis is left to right, so clock wise would be looking from the free end, usually the RHS, assuming the bobbin is put on the right way 'round, in any event, all the start dots have to have their wires go the same way 'round the bobbin ...