Coils and Laminations

[Big Vern]

Good Evening,

I am looking to get some coils wound onto some laminations, to make a two phase linear motor...my question...are the coils wound onto the stacked and bonded laminations, or does the coil get wound separately, and the lamination stack built around the pre formed coils? In this instance, the 'gap' the coils would have to squeeze through it quite small - however - I presume the coils could be flattened to get them to fit?

Second question - does the varnish get painted onto each lamination, or is it applied just to the outside of the stack? The coils I have in mind are for a low voltage application (circa 8/12vac)

Many thanks in advance for my education,

Paul.

[lurcher]

Depends on the Core. For Ei or C, the bobbin is filled then the core added. For Toroid a special winding machine is used.

You can apply varnish by hand as the turns are added, but normally vacuum impregnation is used.

I have tried many times to describe how a toroid is wound and every time it fails, so here is a video.

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[Big Vern]

Thanks, Nick...very helpful, Sir :)

Best Wishes,

Paul.

[Barry]

Thanks for the video Nick. For a long time I have wondered how toroidal transformers were made. Your video helped a lot, although I would like to watch it in slow motion, as it is still not clear how the wire is transferred from the supply toroid to the one being wound.

It never ceases to impress me, the inginuity shown by the designers of such machines. The sewing machine is one such example.

[Welder]

Good grief. That brings back memories of hand winding transformer coils when I was a lad. :)

[Marco]

All I got when I clicked on Play was 'This video is Private', and so it wouldn't show me anything... How did you guys view it? :scratch:

Marco.

[lurcher]

Here is another one, thicker wire so slower and show just how the unspooling happens.


http://www.youtube.com/watch?v=oBdJvT7tpSM

[Marco]

Now that video works, Nick! What happened to the other one....?

Marco.

[lurcher]

The owner must have taken it down

[Marco]

Yup, they must've done. Seems strange, though, how Paul, Barry and John (and presumably you) managed to view it before that happened... Perhaps he or she took umbrage to the video being posted on here?

Weird! Not to worry :)

Marco.

[lurcher]

The key to the unspool (Barry) is that the loaded spool of wire is not coupled to the bobbin thats doing the unspooling, some one rotates keeping the tension constant and winding on the core, while the other just has the wire pulled off. You can see in the last video how the rate changes.