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Re: Pancake coils

Michael,

What I will be attempting to build is a kicking coil apparatus as described
in Curtis's book: Experimental High Frequency Apparatus, 1916.

These type of coils were used in early medical equipmet to power x-ray
tubes etc.

I have pictures of some early medical apparatus that are similar in circuit
design at: http://www.albany-dot-net/~zardoz/quackers.html

Note the first machine made by Rose. It uses a pancake coil that is wound
beneath the primary (same thickness) and is attached to the primary. It uses
ac to power the kicking coil (like an induction coil, except it only has a
secondary, no primary) . Two of the other machines (one by McIntosh) also
use pancakes and kicking coils. (The Aloe uses a transformer and a Tesla
coil, the secondary is not connected to the primary.)

Of perticular interest is the first machine (the Rose). It runs off ac or
dc. It
has
two motors , one ac and one dc, although they appear identical. When using dc,
the switch in with the motors is switched from ac to dc, and the dc motor runs
and
operated the ac motor as a generator to supply ac to the machine.

The large pancake coil I am building will use ac only.

-Pete

Tesla List wrote:

> Original Poster: "Michael Novak" <Acmnovak-at-execpc-dot-com>
>
> Peter-
>
>     Are you attempting to build something similar to a disruptive discharge
> coil?  I'm thinking of making one myself, and, like you, have a hard time
> with the hard rubber insulating material.  I doubt it matters that much,
> because, back in Tesla's time, there wasn't exactly an Ace or home depot at
> every corner he could just stop in and buy some pvc...
>     And, as for the oiled paper, I would try to make something similar. If
> you look in most HV transformers and ac capacitors, you'll find a similar
> material... I'm not suggesting you use that material, but a homemade version
> of it.  Try using butcher paper soaked in mineral or hv oil.
> Good Luck
>                                                         -Michael
>
> ----- Original Message -----
> From: Tesla List <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Monday, February 07, 2000 3:54 AM
> Subject: Pancake coils
>
> > Original Poster: peterB <zardoz-at-albany-dot-net>
> >
> > Hello,
> > This is my first post to this list.
> >
> > I am planning to build a 'kicking coil' outfit based on plans in Stanley
> > Curtis's book
> > 'Experimental High Frequency Apparatus..'.
> >
> > I have read through many of the archived posts looking for answers to a
> > few questions
> > and have only found a partial answer for one question, (for a different
> > application,
> > however)
> >
> > My first question concerns the winding of the secondary, which is 150
> > layers of 30 awg dcc
> > wire, each layer separated by 'oiled paper' .003" thick.
> > I am looking for a suitable substitute for 'oiled paper'. I am not sure
> > of heat buildup
> > inside the primary, so this may be an issue.
> > I have considered parafining regular paper for this, but this job may be
> > a bit much,
> > especially if there is an 'off the shelf' item available.
> > I was also considering 'empire cloth' (not available anymore) but I
> > believe it is simply
> > varnished cloth. If this is what it is, this may be a feasible option.
> >
> > Question 2: I have about 10lbs of 26awg dcc wire (old) and for that
> > reason many of the coils
> > (including the above mentioned pancake that calls for 30awg) will be
> > using this.
> > I have seen some formulas for wire use, # of turns etc, but none that
> > would allow me
> > to plug in 26awg and spit out coil length, # of turns etc. Is there a
> > method of determining
> > secondary construction when I am limited to a certain awg?
> >
> > Also, relating to the above two questions, certain dimensions for the
> > pancake are based on the
> > 30awg wire. ex.-spacing of the turns, number of turns per inch etc.
> > I am wondering if I can use simple algebra to scale up all the
> > dimensions using 26 instead
> > of 30awg. for ex: using 30awg, the width of the layers shows as 1" turns
> > spaced 1/8"
> > apart(First 50 layers). so- 30/1=26/x, solve for x to get the new width.
> > Will this be ok to scale all
> > dimensions?
> >
> > Q4: The plan calls for a 'hard rubber' cylinder drilled lengthwise
> > through the center to accept
> > a brass rod, the top of which suports the discharge ball. Any sources
> > for 'hard rubber' rods
> > (about 1 1/4" diameter) or substitutes?
> >
> > Last question: The capacitor is 20 units of 10 plates each equiling
> > .1mfd. (I do not know what
> > the voltage should be, this coil uses ac that powers a kicking coil)
> > What would be a modern
> > equivelant?
> >
> > Thanks for all your help.
> >
> > -Peter B.
> >
> >
> >
> >