Year: 1886

page_text: I, WILLIAM STANLEY, Junior, of Great Barrington, Massachusetts, United
States of America, Electrician, 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 :—
My invention relates to the construction of induction coils or inductoriums.
The object of my invention is to so construct an induction coil that from a given
weight of metal in the primary and secondary conductors, and in the core a higher
electromotive force will be developed, than in the ordinary forms, and the cou-
sequent efficiency of electric conversion per unit of weight of apparatus will be
increased; and a further object of my invention is to provide convenient means
for modifying the electromotive force developed in the secondary coils.
My invention consists in giving to the core of the coils an annular form, the ends
confronting each other but separated by a small space.
The extent of this separa-
tion is rendered variable by means of an adjusting screw of non-magnetic material,
acting upon the respective ends so as to cause them to approximate or recede from
each other as desired.
A special application of the invention is in the case of inductoriums employed
in certain systems of electrical distribution for incandescent electrical lighting in
which intermittent or alternating electric currents are transmitted through the
primary circuits of the coils the lamps being placed in the secondary circuits. The
conversion of electromotive force by means of such coils is not only rendered more
economical and practical by this invention, but by varying the distance between
the ends of the core and thus varying the electromotive force of the secondary, the
intensity of the lights may be easily and conveniently modified and the brilliancy
of illumination in different lamps may thus be rendered uniform.
The primary and secondary coils may be superposed one upon the other, or they
may be wound parallel with each other or their different layers may alternate
accordingly to circumstances.
In the accompanying drawings figure 1 is an elevation partly in section, of an
induction coil embodying the features of my invention. Figures 2 and 3 show a
modification of the same.
Referring to the drawing, A represents an annular core having its ends at a¹, a²,
confronting each other. The core is formed as usual of soft iron and may consist

page_text: either of a single piece of metal or of a bundle of separate wires or strips as found
desirable. A primary coil b¹ encircles this core the terminals of which are shown
at e¹ and e2. The secondary coil b2 is shown in the drawing as superposed upon
and exterior to the primary coil, but its situation in reference thereto may be
varied as already stated. Its terminals are shown at e³ and e.
The ends of the core may be left free, but preferably they are provided with
non-magnetic projections f₁f through suitable holes in which extends a two-way
adjusting screw f. By means of this screw the proximity of the two confronting
ends of the core may be readily varied.
In figure 2 a slightly modified form of coil is shown, its core being somewhat
rectangular in form, having curved angles g', g², g³ and g‘. The primary coil b¹ is
shown in this instance as being wound with alternate layers of the secondary
coil b. The confronting ends of the core are provided with non-magnetic pieces f³
and and the adjusting screw f extends through one piece c¹ and bears against
the other c², the core being constructed so that its ends tend to spring toward each
other while the screw serves to separate them as required.
Instead of adjusting the ends of the core toward and away from each other a
movable soft iron piece h may be employed as shown in figure 3. This may be
moved away from or into greater proximity to the poles by means of a screw h¹.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. An induction coil or inductorium consisting of parallel primary and secondary
conductors, an iron core within the same forming an approximately closed magnetic
circuit, and means for modifying or varying the magnetic resistance of the closed
magnetic circuit.
2. An induction coil or inductorium provided with a core having its ends con-
fronting, means for varying the distance of said ends from each other and primary
and secondary coils upon said core.
3. In combination with an induction coil, having the ends of its core confronting
each other,, a non-magnetic device for adjusting the distance of said ends from
each other.