RF coil winding directions

[Malcolm T]

Never questioned this before but is there an internationally recognized direction for winding RF coils . After winding several coils i found i had wound them in the opposite direction to what i had previously done years ago. Looking at commercial coils i have and comparing them it seems they are all in the same direction , useful i suppose if you observe the same direction and want to use them with home brew coils !.
Any thoughts on this one , i was always told wind your coils in the same direction for coupling purposes .

[joebog1]

I think they are all wound the same because they are wound on a coil winder. The chuck rotates towards the operator, not away from the operator. Like a lathe, you would need the slide and cross bed to be above the centre, not below it. Left hand threads are still cut on a lathe that turns towards you, not away.


Joe

[Skywave]

The coils that you have seen where the direction of the winding was in the same direction for all of them - e.g. all clockwise or all anti-clockwise - would have been because these coils were machine wound: that machine 'called the shots', so to speak.
If there is only one winding - tapped or not - the winding direction (c/w or anti-c/w) is irrelevant.

However, if there is more that one winding on the one former - every winding being electrically isolated from all the others - say two windings - then the winding directions are indeed important: inter-winding coupling will exist, known as mutual inductance. Such coils are often referred to as 'r.f. transformers'.

The same consideration also exists if there are two windings, each on its own former, but with the coils spaced apart so that the magnetic field from one coil induces a current in the other. Again, an example of mutual inductance.

An illustrative and comparative example arises if I have a mains transformer with two secondaries of, say, 10v. and 8v. I can join the output wires in two ways to give 10v. + 8v. or 10v. - 8v. All a question of phase; mutual inductance is much the same: aiding or unaiding the respective inductances.

Al. / Jan. 7th.

[Malcolm T]

Yes i take all your points given there . Yes the winding machine just like a lathe makes sense.
Getting the turns in the same direction is important where the turns interact i do agree .
I suppose it was all down to the manufacturer and customer requirements .

[Ed_Dinning]

Hi Joe, on the 2 hand cranked winders I have they both go in the opposite direction to a lathe, fed on to the top of the winding, chuck rotates away from the operator.
I know this is correct as that is the way that the counter increments; other direction causes it to decrement.

Ed

[joebog1]

I have never seen a hand cranked winder. I guess the chucks must be fitted to a morse taper. Ordinarily the chuck would unscrew although I have only played with two winders. Dads and my own Glow winding machine. Dads was home made ( it was built at his work, but all his work and design ) consisting of a 4 HP electric motor coupled to a Morris gearbox that still had the clutch attached.

Joe

[Malcolm T]

Looked at quite a few sites and seen plenty of winders , commercial and homebrew , quite ingenious designs , simple to complex .
So is this diagram correct then ? L/H and R/H sense . In both cases the coil is wound away from the viewers eye.
https://electronics.stackexchange.co...utput-polarity

[Ed_Dinning]

Hi Joe, winding with RH, headstock at that end obviously and chuck tightens with winding ans is mounted on a screwed stud.
Not worked with anything as powerful as yours, but most of the smaller UK motorised machines worked in the same direction.

Ed

[joebog1]

Dads machine was used to rewind distribution transformers. Mine can take about 1000 watt EI bobbin.

Mine is 1/4 horse, and is fitted with the same clutch as an industrial Singer sewing machine.

Joe