Insulation of enameled copper wire

Tangent Delta from the SYNFLEX Magnet Wire Encyclopedia

"Dielectric loss factor. Only ideal insulations have no ohmic drops. Insulations like enamels have a minor, but yet verifiable dielectric loss (similar to capacitors), mainly the so-called dipole friction loss.

Impressing an alternating voltage on an enamel coat, the dipoles of the molecular structures start vibrating and experience resistance causing friction and heat. Such friction losses are dependent on the chemical composition and significantly on the annealing of the enamel.

There is special equipment for testing the dielectric losses depending on temperature. It takes a certain temperature to loosen the molecular structure permitting a strong increase in dipole movement. This increased movement results in a significant rise in the loss factor (tan delta point of inflection). The stronger the grade of annealing the higher the point of inflection. This makes the tan delta test a good indicator for the annealing grade of enamel insulations.

The features of magnet wires strongly depend on the grade of annealing, and therefore such tests allow conclusions on the performance of a magnet wire."

Tan Delta Magnet Wire Testers

DSE A/S (Formerly Dansk System Elektronik A/S) is a Danish company. www.dse.dk/

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Regards
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com

Hello to all
I am new in this business and for this reason I have a lot of questions.
1. How can I produce very soft magnet wire or very hard ?...witch temperature in the annealer? what is the influence of the enamel ling oven for softness of the wire?
Thank You

There are two very good magnet wire engineering specialists that usually monitor the Forums and answer questions. One of them, Tech1, has not been around for some period of time and the other, "Spectre07" is extremely busy at the moment. He won't be available for some period of time.

Sorry for the delay but please have patience. Thank you.

Regards,
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com

Hello Raul,

I assume when you say soft or hard you are not talking about the cure or durability of the enamel coating on the conductor. I also assume you are talking about copper magnet wire.

Softness is a realative term. There are two types of measurements that are sometimes thought of as "softness or hardness".

The first is elongation sometimes people will say the wire is soft because the elongation value is big -30-50%. This is actually a measure of tensile strentgh/yield.
The other terminology is springback another test specific to magnet wire. Spring back is a coil winding test in which you then measure how much the wire springs back (basically trys to uncoil). This is actually a measure of ductility.

So the real question is which are you interested in; high elongation or good ductility?

A real quirk in manufacturing is that wire enameled on a machine that includes inline wire drawing can have both a high tensile strength and good ductility.

Annealing like curing enamel is a time temperture relationship. The ideal temperature is related to the length of the annealer and the speed the wire is moving through it. Also the device you are calling the annealer is more correctly called a pre-annealer as the majority of the annealing process takes place in the enamelling oven and not the annealer.

spectre

raul,
when you are making "off spec" or specialty wire sometimes the only thing that you have to go by is what the end user tells you what measurement they wants the wire to meet.

We used to make a polyimide wire that the enduser called 46 awg. He had four different specs for resistance but at the same time had to stay withing the dimensional specs for 46 awg. We did it but it waa not easy.

If the customer provides the spec he cannot realistically require you to hold to a rectangular shaped wire spec if you are not making that wire.


I know that you said you could not coat shaped wire because of you equipment but I really think that a way to do it would be to put your post rolling machine between the annealer and the applicator. You would have to take some action to prevent the wire from rotating but I know some technicians that could do.

I don;t know what type post rolling machine you have but a very small turks head from BHS-Torin would work.


rb