Stubblefield coils (bifilar) and speculations

[jeanna]

Hi everybody,

I am posting this here because it seems to belong with the iron winding element of stubblefield, somehow.

I have just gutted 3 cfl's in the last week.
I find it very surprising that the 2 filaments coming out of each tube are made of iron.
I also wonder how significant it is that there are 7 turns of this iron wire around a NON ferrous metal post??

Well there you have it.


jeanna

[IotaYodi]

2 pin cfls have a starter with a magnetic preheat ballast. That may be the reason for the iron wire.  4 pins are usually electronic ballasts and don't  have an internal starter.

[jeanna]

Wow
Gravity block just gave me some important info on the jt topic.
I do not get why he thought it was important, there, but you guys are gonna love this.
I copied this from wiki
======

From Wikipedia, the free encyclopedia
Jump to: navigation, search

The Wiegand effect is a nonlinear magnetic effect, produced in specially annealled and hardened wire called Wiegand wire.

Initially, Wiegand wire is low-carbon Vicalloy (an alloy of cobalt, iron, and vanadium) wire, fully annealled. In this state the alloy is "soft" in the magnetic sense- that is, it is attracted to magnets (it is ferromagnetic and so magnetic field lines will divert preferentially into the metal) but the metal retains only a very small residual field when the external field is removed.

Then, the wire is subjected to a series of twisting and untwisting operations, to cold-work the outside shell of the wire, while retaining a soft core within the wire, and then the wire is aged. The result is that the magnetic coercivity of the outside shell is much larger than the inner core. This high coercivity outer shell will retain an external magnetic field even when the field's original source is removed.

The wire now exhibits a very large magnetic hysteresis loop - if a magnet is brought near the wire, the high coercivity outer shell excludes the magnetic field from the inner soft core until the magnetic threshold is reached, at which point the entire wire (both the outer shell and inner core) rapidly switch magnetisation polarity. This switchover occurs in a few microseconds, and is termed the Wiegand effect.

The value of the Wiegand effect is that the switchover speed is sufficiently fast that a significant voltage can be output from a solenoid using a Wiegand-wire core. Because the voltage induced by a changing magnetic field is proportional to the rate of change of the field, a Wiegand-wire core can increase the output voltage of a magnetic field sensor by several orders of magnitude as compared to a similar coil with a non-Wiegand core. This higher voltage can easily be detected electronically, and when combined with the high repeatability threshold of the magnetic field switching, making the Wiegand effect useful for positional sensors.

Once the Wiegand wire has flipped magnetization, it will retain that magnetization until flipped in the other direction. Sensors and mechanisms that use the Wiegand effect must take this retention into account.

The Wiegand effect is a macroscopic extension of the Barkhausen effect as the special treatment of the Wiegand wire causes the wire to act macroscopically as a single large magnetic domain. The small high-coercivity domains in the Wiegand wire outer shell switch in an avalanche, generating the Wiegand effect's rapid magnetic field change.

==========
thank you,

jeanna

[kukulcangod]

Hi to everyone
                     I wonder if anyone one knows a source to machine acrylic pieces to make a coil like Lasersaber's , I plan to make them big and in series parallel, but I tried sources online like emachine , that are never available and required expensive huge orders, now , I live in the usa, but as right now I have to live in a remote part of the world where I have not chance to do this no reliable source , certainly my solitary free time is fullfiled with this ideas I have the other materials but can't cut with precision like I need for my own setting
I will appreciate any help in this regards
Cheers

[Pirate88179]

Hi to everyone
                     I wonder if anyone one knows a source to machine acrylic pieces to make a coil like Lasersaber's , I plan to make them big and in series parallel, but I tried sources online like emachine , that are never available and required expensive huge orders, now , I live in the usa, but as right now I have to live in a remote part of the world where I have not chance to do this no reliable source , certainly my solitary free time is fullfiled with this ideas I have the other materials but can't cut with precision like I need for my own setting
I will appreciate any help in this regards
Cheers

Just a thought for you.  If you are speaking of the end cap pieces, they do not have to be round.  You could make them square, which is much easier to do, and as long as you made them large enough, it should work just fine.

Bill