Improvements in Electric Dynamos, Electric Motors, Transformers of Electric Currents, and Induction Coils.
Year: 1890

page_text: Date of Application, 7th Oct., 1890 -
Complete Specification Left, 4th July. 1891-Accepted. 22nd Aug.
1891
PROVISIONAL SPECIFICATION.
Improvements in Electric Dynamos, Electric Motors, Transformers of
Electric Currents, and Induction Coils.
JAMES JOHNSTONE Proprietor of No. 8 Merchiston Park, Edinburgh, Theologian,
Electrician, and Engineer do hereby declare the nature of this invention to be as
follows:-
The improving of the electric current producing portion of the above named
machines by inserting within its course in each machine metalic vessels containing
air or any of the gases at the pressure of the atmosphere, but sealed up so that the
external air has no communication with the secluded air or gases within the said
metalic vessels. Also, if required by an operator, the secluded air or gases may
be rarefied within these metalic vessels, either by the application of heat, or by
means of an air-pump; suitable apertures being made a part of these vessels for
this purpose.
Dated this Sixth day of Dotchou 1000
JAMES JOHNSTONE.
COMPLETE SPECIFICATION.
Improvements in Electric Dynamos, Electric Motors, Transformers of
Electric Currents, and Induction Coils.
I JAMES JOHNSTONE Proprietor of No. 8 Merchiston Park, Edinburgh,
Theologian, Electrician, and Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
Owing to experiments I made in 1839 I discovered and published that year that,
there is only one kind of electricity, not two as is commonly supposed, and that it
is a peculiar kind of matter, and is the ether of the astronomers. These experiments
and the results of them have been recently republished in the first, and second parts
of a Treatise on Electricity which may be had from me through any bookseller.
The holding of these particular views concerning the nature of electricity led to
my inventions through my reading in The Electrical Engineer of 19th Sept. 1890
an article by the editor, in which he described a phenomenon he had just witnessed
at a trial of a part of new electric mains then being laid down between Deptford
and London by Mr. Ferranti. Which phenomenon is now known as "the Ferranti
effect."
This phenomenon is a rise of the voltage of the current of electricity sent
through these inains, instead of a fall of the voltage of the current as had been
experienced with all previously constructed electrical mains. Some electricians
have asserted that, "the Ferranti effect is an old well known phenomenon which
has appeared under new circumstances, but I have no faith in these statements
because they have not been supported by experiments made under the exact same
circumstances of external insulation as when the Ferranti effect "appeared in the
original form of his electric mains.
The opinion hold concerning the Ferranti effect," and which led to the
inventions herein described will be understood after reading the following description
of the original form of the Ferranti mains.
These mains are made of two copper tubes, one placed inside of the other with
insulating material between them, and also outside them. These tubes are made in
lengths of 20 feet.
The inner of copper is inch thick, and inch of internal
D

page_text: diameter. Outside of this tube is a half inch thickness of paper saturated with
ozokerite, and then the outer copper tube is slipped over the paper. The outer
tube is then covered with paper saturated with ozokerite, and over all is placed a
steel tube for protection. These 20 feet lengths of compound tubing are joined
together by one end of each of them being coned, and the other end hollowed to
receive the cone, and a copper plug of about 18 inches in length is inserted within
the inch'orifice of the inner tube, one half of the length of this plug being in cachi
of the adjoining 20 feet tubes. These plugs hold the lengths of tubes firmly
together. The plugging of these tubes converts each tube into a separate air-
vessel of inch diameter, and about 18 feet in length. It is alternating currents of
electricity which Mr. Ferranti sends through these mains. Now as electricity is a
peculiar kind of matter, it follows that at each time these currents of electricity are
forced through and reversed within the copper of the inner tube a concussion takes
place between the atoms of the reversed currents, and as the inner copper tube is
clothed with half an inch thick of waxed paper the concussed atoms of electricity
cannot get out with freedom through the half inch of waxed paper, part of these
atoms are forced into the air space within the tube; for experiments both ancient
and modern prove that air can be surcharged with electricity. The concussed
atoms of electricity having been forced into the air spaces of the tubes they easily
find their way from the air-vessel in one tube to the air-vessel in the next tube,
because the copper plug between two air-vessels is not influenced by the alternating
currents oscillating backward and forward in the metal of the tube which incloses
the plug. The accumulation of these concussed atoms of electricity within the air
spaces and the passage of them from air vessel to air-vessel is one of the causes of
"the Ferranti effect." And it is also a reason why these mains do not become
over heated by the electricity.
Being a firm believer in the foregoing described advantages of this system I saw
that it could be applied to dynamos, electric motors, transformers of electric
currents, and induction coils by inserting air-vessels in the course of the electric
currents in these machines. For this purpose the air-vessels may be of two kinds.
First, tubular in shape. Second, in the form of metal boxes. For the tubular
kind all that is necessary is to procure metal tubing of small bore, and treat it as
metal wire is now treated in making the several electrical machines above named.
The value of these tubular vessels will be greatly enhanced for the purpose in
hand by the air in them being rarified either by the application of heat to the
tubing before it is clothed with the usual insulating covering, or by the air being
exhausted out of these tubular vessels by means of an air-pump, either before or
after the tubing has been rolled on to the machine it is to cover. Second, by boxes,
these may be of a variety of shapes according to the peculiar construction of the
machine to which they are applied. For the sake of explanation I shall direct
attention to the alternating dynamo invented by Mr. Mordey, and show how these
boxes might be applied to it. The field magnets of his dynamo revolve and the
armature is fixed, and consists of a number of segments all set within a metal ring.
Fig. 1 corresponds in shape to one of these segments. The inner part A of the
segment is made of slate, being a good insulating material which can be firmly fixed
to the outer metal ring, and also fixed to the part B, without electricity passing
from B to the metal ring. The part B is composed of a core of insulating material
on which is rolled coils of narrow copper ribbon. Now instead of these cores of
insulating material there might be substituted metal boxes cast of the required
shape, and the boxes would be placed in metalic contact with the copper ribbon at
such parts as it was found gave the best results.
Again an armature for Mr. Mordey's dynamo might be made with boxes without
a clothing of copper ribbon to cover them, as follows. If metal boxes be made
with flanches so that they would grasp the slate segments, and at each end of each
box, a metal tube be connected, and of sufficient length to pass through, the metal
ring, and insulated from it by means of the porcelain insulators such as Mr. Mordey
uses to insulate the wires of his segments. On each of these tubes being united

page_text: with the tubes of the segments adjoining, so that an air passage be made, by these
tubes, between the boxes of the segments, and after the whole armature be thus
constructed, and an air-pump applied at a stopcock provided on the dynamo for the
purpose, so that the air might be extracted from all the boxes of the segments,
these boxes of the segments would give a current of electricity on the dynamo
being set in motion. The boxes for these purposes may be made of cast metal, or
they may be built up of pieces of sheet metal united by soft or hard solder.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is :
1. The making or using of metalic air-vessels for holding secluded air or gases
in the field magnets or armatures of dynamos, or the placing of these air-vessels in
the line of the electric current of electric motors, transformers of electric currents,
and induction coils.
2. The using of the said secluding air-vessels either as containing air or gases at
the pressure of the atmosphere, or rarified by the application of heat, or by means
of an air-pump.
”מ
Thof 1.1. 1801
JAMES JOHNSTONE,
Applicant.