IMPROVEMENTS IN AND APPERTAINING TO COILS FOR ELECTRO-MAGNETS AND OTHER PURPOSES.
Year: 1880

page_text: LETTERS PATENT to George Scarlett, of Liverpool, in the County of Lancaster,
for an Invention of "IMPROVEMENTS IN AND APPERTAINING TO COILS FOR
ELECTRO-MAGNETS AND OTHER PURPOSES.".
PROVISIONAL SPECIFICATION left by the said George Scarlett at the Office
of the Commissioners of Patents on the 17th April 1880.
GEORGE SCARLETT, of Liverpool, in the County of Lancaster.
* IMPROVEMENTS IN
AND APPERTAINING TO COILS FOR ELECTRO-MAGNETS, AND OTHER PURPOSES."
In making electro-magnets the present plan is to wind the wire on the coro in
one continuous series of helices from right to left and back again, and so on until
thero is sufficient wire to effect the magnetisation of the core, or in the case of
horse-shoe magnets right-handed belices on one arm and left-handed helices on the
other, coupled or united together so as to make one continuous length, through
which the clectricity passes in a single or intermittent current.
Now my Invention, applicable alike to coils used in electro-motive, magneto-
electric machines, and other electrical apparatus, consists in a new manufacture of
coil as follows:-I wind two or more coils or helices of wire, each of the same
resistance as the line in telegraphy or of the producer of electricity in electro
magnets, round the same core, or two or more independent wires insulated from
cach other in the same coils or compound helices. Usually indeed I form the
insulating bobbin on which they are bound in as many separate divisions as there
are wires, a division for each wire, so as to effectually insulate them the one from
the other. Thus, presuming that there are two bobbins, and each bobbin is divided.
into two parts, there are four helices or coils with eight ends, four from the bottom
or beginning of the coils, and four from the top or finish of the same. Now sup-
posing that they are all right handed or all left-handed coils, I unite the four bottoin
coils to one terminal of the battery or generator of electricity, and the other four to
the other terminal of the said battery or generator (I prefer to have all the coils
wound the same way, say all right-handed, as it saves confusion, though this course
is not absolutely necessary); I then place the cores in the centres of the bobbins,
and thus get a magnet far superior in power to one with a single continuous length
of wire, as in the ordinary construction.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Scarlett in the Great Seal Patent Office on the 16th October
'1880.
GEORGE SCARLETT, of Liverpool, in the County of Lancaster "IMPROVEMENTS IN
AND APPERTAINING TO COILS FOR ELECTRO-MAGNETS AND OTHER PURPOSES."
In making electro-magnets the ordinary plan is to wind the wire on the core in
one continuous series of helices from right to left and back again, and so on until
there is sufficient wire to effect the magnetization of the core, or in the case of
horse-shoo magnets right-handed helices on one arm and left-handed helices on the
other, coupled or united together so as to make one continuous length, through which
the electricity passes in a continuous or intermittent current.
Now my Invention, applicable alike to coils used in electro-motive, magneto-
electric machines, and other electrical apparatus, consists in a new manufacture of coil
as follows: I wind two or more coils or helices of wire round the same core, or two
.or more independent wires insulated from each other in the same coils, or compound
helices, each division of the coil being of the same resistance as the line in telegraphy,
or of the producer of electricity in electro-magnets, whereas in former coils as
ordinarily made the entire amount of wire was made to be equal to the resistance
of the line. Usually indeed I form the insulating bobbin on which they are bound
in as many separato divisions as there are wires, a division for each wire, so as to
effectually insulate them the one from the other. Thus, presuming that there are
two bobbins, and each bobbin is divided into two parts, there are four helices or
coils with eight ends, four from the bottom or beginning of the coils, and four from
the top or finish of the same. Now supposing that they are all right-handed or all
left-handed coils, I unite the four bottom ends to one terminal of the battery or
generator of electricity, and the other four to the other terminal of the said battery
or generator (I prefer to have all the coils wound the same way, say all right-
handed, as it saves confusion, though this course is not absolutely necessary). I
then place the cores in the centres of the bobbins, and thus get a magnet far
superior in power to one with a continuous length of wire, as in the ordinary con-
struction. It is not necessary however to place each wiro on a separate part of the
bobbin, as I frequently wind two or more insulated wires together upon the samo
division of the bobbin.
In the Drawings taken from actual coils Fig. 1 shows a horse-shoe magnet wound
with eight independent wires; Fig. 2, a bobbin for use in telegraphy wound with
two independent wires; the wires are purposely shown not neatly or securely
fastened at each end of the coil, so as to show the direction of winding. The
dimensions of theso individual coils as samples are as follows:-In Fig. 1, coro
three eighths of an inch in diameter; wire, No. 30, depth of wire in coil, five eighths
of an inch; width of each separate coil, five eighths of an inch; diameter of coil one
inch and seven eighths; number of feet in each wire, one hundred. Fig. 2, core
three eighths of an inch in diameter; wire No. 30, depth of wire in coil half an
inch, width of each separate coil, three eighths of an inch; diameter of coil, one and
a half inches; number of feet in cach wire, seventy five. The main points to be
noticed in these coils are that the depth of coil should not be less than tho diameter
of the core, either in a single or in a double wound coil.
With electro-magnets the resistance of each wire taken separately should be equal
to the resistance of the cell or source of electricity used, while in telegraphy it
should equal the resistance of the line. In this respect my coil differs from all
attempts at winding the coils in multiple are made hitherto. The idea of winding
in multiple arc is not new; it has often been tried, but has always proved a failure,
and for this reason, that the depth of wire used was always far too little. If two

page_text: independent wires be used instead of using only the same quantity of wire, as with
one double the quantity is required. Hitherto only the same quantity has been
used. The result in increased power from my mode of making coils is very great,
a single cell producing, as near as I can estimate, about double the power with my
coil of, say four wires, that is gained where a single wire is used, or where four
wires unitedly the length of the said single wire are employed. The cause or reason
of this I believe to be that while the resistance of the entire coil is reduced a
secondary current is formed in each wire induced from its companion wires, and I
have found as a result that a spark from a battery with one of these coils in circuit
is far greater than a spark from the same battery without the additional resistance
of my coil; whereas with an ordinary coil in the same position it is much less, thus
showing conclusively that a mutually induced current is set up in every member of
the multiple arc, and that this induced current is in the same direction and aids the
primary current.
Having now described my Invention, and the best mode known to me of carrying
it into effect, I wish it to be understood that what I believe to be new, and desire
to protect under the hereinbefore in part recited Letters Patent is,-
First. The manufacture of coils for use in electric, electro-magnetic, or magneto-
electric apparatus, in which several independent wires insulated from each other,
except at their ends, are wound upon the same reel, bobbin, armature, or core, ench
strand being of approximately the saine length of wire that would be required if
only one strand were used, namely, a length that will give resistance equal to the
resistance of the line, wire, or the cell or other source of electricity used, and
preferably of not less depth of wire than the diameter of the core.
Second. The coils formed of several wires insulated from each other, except at
their terminals, manufactured and arranged substantially as herein described.
In witness whereof, I, the said George Scarlett, have hereunto set my hand
and seal, this Fourteenth day of October, in the year of our Lord 1880.
Witness,
WM. P. THOMPSON,
Of Wm. P. Thompson & Co.,
Patent Agents,
Liverpool & London.
GEORGE SCARLETT. (L.S.)