Hand wind toriodal transformer help please

Wow, that's a lot of turns, what is the use for your transformer? And what material is the core? Mike

ews=3D=3D----

You may find it helpful to follow the suggestion to wind double strands, even if you don't need a center tap. Paul Mathews

Usually the primary is first since the resistance loss of the copper is less that way. Interleaving - bifilar -trifilar etc. are good for tight coupling and making sure you don't miscount turns - when turns count is more important than other considerations.

The answer to your question is probably separate windings - you have a lot of turns. Separate windings reduces the capacitive coupling and may lower losses.

As the number of turns goes up - the exact count is usually less important.

No. You don't say if the phasing of the windings is important to your application . . . If you wind in two directions one of the "start" windings will be out of phase with the other "start," so a "finish" will be the same as a start on one winding - simply switch them around

The black dot on the schematic indicates similarly phased windings - if it matters.

Seems to me it would have to. If there's a reason to lower capacitive coupling, or a high voltage differential between windings, wrap with some tape (thin Mylar transformer tape is good - not necessarily adhesive, or Teflon plumbers tape works for amateurs) will keep one winding from burrowing into the other.

Consider the voltage - a two hundred volt differential between two wires with enamel insulation is the most you can get away with.

Yes. as a general rule, but you have to decide if the construction lends itself to that.

I can't count to 600 when winding . . . so I use length only.

If a winding has to have a CENTER tap and has to be exactly in the center - I fold the wire double and wind both together, then cut and connect one "start" to the other "finish" to phase it for a center tap - this also helps keep the voltage and resistance loss balanced.

Make a shuttle to hold the wire. Cut a stick or plastic piece or wood dowel - that will easily fit through the center of the core (long narrow strong and something that won't scrape the insulation off the wire) - with a notch to hold wire on either end. Then wind the stick with your wire. The length of the stick is sized to hold all the wire - shorter is easier to handle but each turn around the shuttle represents a few turns around the core - so the core builds up faster than the shuttle depletes - you keep that in mind.

The shuttle aids in passing the wire through the center without getting it kinked.

A small rubber band can hold the wire on the shuttle if you have to stop for something (or a few pieces of cut tape can be handy).

In a thread several months ago there was a discussion about toroids, and apparently there can be a problem if you continue to wind in one direction for multiple layers. What I understand is that each layer constitutes one turn around the axis of the core. So you should wind one layer, and then continue to wind the other way for the second layer, and continue this process.

For that many turns, it might be easier to bundle ten strands together, so you will only have to make 20 and sixty turns. But then you need to join each start to end.

That is a lot of turns for a ferrite toroid, and indicates either a very high voltage or a rather low frequency. Depending on material, you should be able to get at least one volt per turn on a core that size at about 100 kHz. It would be interesting to know your specifications.

Paul

Thanks for everybody's replies, they were a great help. Especially putting the secondary onto a shuttle, it was impossible for me without it!

Thanks again in advance for any help :)