- About me
- A university trained Professional Mechanical Engineer, registered in the Province of Ontario, Canada.
A wire and cable manufacturing engineering specialist with over 35 years hands on experience.
- Peter J Stewart-Hay replied to the topic 'Compatability-Enameled Cu wire with transfr oil' in the forum.Hello Udaya,
Well let's think about your question for a minute.
1 - There are likely millions of oil filled transformers around the world and mostly all contain enameled coated wires to step-down voltages.
2 - There are many different manufacturers of transformer oils around the World and although these oils are all very pure, it is important to determine which one(s) you are dealing with.
3 - There are many different manufacturers and types of magnet wire coatings throughout the World so it is important to determine the manufacturer(s) and coatings you are referencing.
4 - It is likely that your magnet wire coating manufacturer(s) already have the information you are seeking so it is important that you provide them with specifics so they can answer your query properly.
You should be able to easily determine the proper and specific answer for your customer.
- In double twisting, you can have a bunch of strands randomly moving about in the finished conductor. Is this what you are doing? It is called double twist bunching.
Likewise in double twisting, you can have a series of strand layers, each closed to control the position of the strands in each layer. Perhaps this is what you are doing. It is called double twist stranding.
In either case, there is excess length in the strands to account for the twist (s) in the conductor. By determining the angle of the conductor twist, use the Pythagorean theorem to account for the excess length in the bunched strands as above and sum to obtain the conductor weight. ( en.wikipedia.org/wiki/Pythagorean_theorem )
In case of double twist stranding, use the angle of strand twist for each layer of strands and sum the weight of each layer to obtain the conductor weight.
- Hello Enrico,
I have checked all my reference books, all over the Internet and used the WAI Education Abstract Search but I can find no information on drawing zinc wire from rod or larger diameter wire. It may therefore take a longer period of time to get an answer because we are dependent upon a qualified reader to provide the appropriate information. I think a fully submerged machine would be the right approach but as far as the elongation goes, it is definitely a question. Sorry I cannot help further.
- Hello again,
In India, a dual sheath is used. The first layer is the standard polyethylene material and the outer layer is semi-conducting, non cross-linked polyethylene. The reason for this is to electrically check at the factory if there are any holes or discontinuities in the first layer.
Perhaps, in your country, they are checking the continuity of the sheath at the factory by using a graphite coating.
PVC is a mixture of a number of chemicals and clay. Sheaths of PVC are generally for inside use but I am aware in Japan of XLPE, EHV cables up to 225 kV.back in the 1970s that had PVC sheaths.
In contrast, polyethylene is a polymer to which a number of chemicals have been added. (UV resistant, color pigment, anti-oxidant and so on. High density polyethylene is also tougher than low or medium density polyethylene. Polyethylene in general well matches the thermal properties of the HV and EHV, XLPE cable cores and is excellent in providing damage and corrosion protection in the heavy cables over the long haul. That is why it is specified .
- Hello Mr. Lua,
We had a discussion about this before.
At that time you indicated that you had purchased a 25 mm elongation tester but that the maximum length between the jaws was only 24.9 mm.
I, as moderator, replied as follows:
"If there is a tolerance on the length of the conductor in the tester itself, it will be in your Standard. I suggest you look up the Standard and read it carefully. If the Standard does not allow a tolerance, then the tester must be modified."
This is still a valid answer as the Standard will clearly define the exact sample distance between the jaws of the elongation tester along with other requirements. We presume you require this for certified test reports to be sent to your customers.