Improvements in the Insulation of Armatures of Dynamo Electric Machines.
Year: 1893

page_text: Date of Application, 11th Feb., 1893
Complete Specification Left, 13th Nov., 1893-Accepted, 6th Jan., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Insulation of Armatures of Dynamo Electric
Machines.
I CHARLES W. JEFFERSON, of Schenectady, in the County of Schenectady
and State of New York, U.S. America, Electrician, do hereby declare the
nature of this invention to be as follows:-
In the construction of dynamos and electric motors, it becomes necessary to
provide insulating heads and inner and outer cylindrical insulating cylinders. I
have experimented with a view to making these insulators of artificially built up
mica scales which invention can be described clearly, only by reference to the
accompanying drawings.
The
The head a has the following construction --Radial mica scales b, are fastened,
together with overlapping edges to form a ring; a concentric ring is likewise
formed of scales b' the two rings not overlapping each other in the construction
shown in Fig. 6. c represents mica scales overlapping each other and forming a
ring connecting the first two named rings which are lettered d and e.
scales c overlap the scales b, b'. Several rings a are made in like manner and
piled on top of each other, cemented with varnish, compressed, and before drying
are moulded by pressure into substantially the form shown in Figs. 1 and 5.
During the process of bending in the mould, the radial and overlapping mica
scales b, b and c slide to accommodate the bending so that, if the varnish is dried
while in the mould, the ring a will take a permanent set which will exhibit the
form shown in Figs. 5 and 1.
The slotted insulator in Fig. 3 is also constructed of lamine made of artificial
mica sheets, constructed in a manner similar to that in reference to the ring
shown in Fig. 6. It is of such a form as to slide into the dove-tailed grooves g in
the armature f. The ends of the slotted insulators h shown in Figure 3, project
beyond the grooves g.
Between the spokes i, are curved insulators ; which are cylindrical with a given
cylinder, except near the ends, which are abruptly bent inwardly against the
spoke. The sheet of which the insulator j is constructed is built up of mica
scales having cemented overlapping joints.
The head m shown in Figures 7, 9, 11, 12 consists of concentric overlapping
rings made of overlapping mica scales n, n¹, n", n¹¹, cemented together and piled
on top of one another as to the concentric rings considered together as a complete
disc. While the varnish is still wet, the flange m' is turned up and thus held
during the process of drying the varnish, after which the head remains as a flanged
insulator. The split cylinder o is also built up of laminated mica sheets each
consisting of scales of mica overlapping. The said cylinder is wrapped upon
a drum armature as in Figure 7. The head m is applied to the end of the
armature in such a manner that the flange m' overlaps the end of the cylinder o.
The mica insulating tube is applied to the shaft q which it fits snugly.
The head is an annular disc with its inner and outer edges flanged and
provided with trapezoidal perforations s, through which pass iron projections t of
the armature core, which is made of a ribbon u wound in convolutions and having
wider portions to form the said projections t. In Figure 17, the strip is
magnified in length and diminished in width for the purpose of illustrating
better that the strip u has an enlarged portion. Upon the trapezoidal projections t
are slipped and held trapezoidal tubes v, so that when wire is wound in the

page_text: usual way, it will be held effectually away from the metallic part of the armature.
On the interior of the armature are pieces of mica insulating sheets j exactly
like that shown in Figure 4.
The trapezoidal tubes v and the circular tube p may be held to the heads by
shellac or varnish. Also varnish may be applied between the heads a, m, and r
and the insulating covering of armature shown in Figure 13.
Dated this 11th day of February 1893.
HUGHES, SON & Co.,
38, Chancery Lane, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Insulation of Armatures of Dynamo Electric
Machines.
I, CHARLES W. JEFFERSON of Schenectady, in the County of Schenectady, and
State of New York, 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 :-
In the construction of dynamos and electric motors it becomes necessary to
provide insulating heads and inner and outer cylindrical insulating cylinders.
have experimented with a view to making these insulators of artificially built up
mica scales which invention can be described clearly, only by reference to the
drawings accompanying the Provisional Specification.
The head a, has the following construction :-Radial mica scales b, are fastened
together with overlapping edges to form a ring; a concentric ring is likewise
formed of scales 1, the two rings not overlapping each other in the construction
shown in Figure 6. c, represents mica scales overlapping each other and forming
a ring connecting the first two named rings which are lettered d, and e.
scales c, overlap the scales b, b'.
The
Several rings a, are made in like manner and piled on top of each other, cemented
with varnish, compressed, and before drying are molded by pressure into
substantially the form shown in Figures 1 and 5.
During the process of bending in the radial and overlapping mica scales b, b',
and c, slide to accomodate the bending so that, if the varnish is dried while in the
mold, the ring a, will take up a permanent set which will exhibit the form shown in
Figures 5 and 1.
The slotted insulator in Figure 3, is also constructed of lamina
made of artificial mica sheets, constructed in a manner similar to that in reference
to the ring shown in Figure 6. It is of such a form as to slide into the dove-tailed
grooves g, in the armature f. The ends of the slotted insulators h, shown in
Figure 3, project beyond the grooves g.
Between the spokes i, are curved insulators j, which are cylindrical with a given
cylinder, except near the ends, which are abruptly bent inwardly against the
spoke.
The sheet of which the insulator j, is constructed is built up of mica scales
having cemented overlapping joints.
The head m, shown in Figures 7, 9, 11, 12, consists of concentric overlapping
rings made of overlapping mica scales n, n', n", nl, cemented together and piled
on top of one another as to the concentric rings considered together as 8
complete disc.
While the varnish is still wet, the flange m', is turned up and thus held during
the process of drying the varnish, after which the head remains as a flanged
insulator.
The split cylinder o, is also built up of laminated mica sheets each consisting of
scales of mica overlapping.
The said cylinder is wrapped upon a drum as in Figure 7. The head m, is

page_text: applied to the end of the armature in such a manner that the flange m', overlaps
the end of the cylinder o. The mica insulating tube p, is applied to the shaft q,
which it fits snugly. The head r, is an annular disc with its inner and outer edges
flanged and provided with trapezoidal perforations s, through which pass iron
projections t, of the armature core, which is made of a ribbon u, wound in
convolutions and having wider portions u¹, to form the said projections t.
In Figure 17, the strip is magnified in length and diminished in width for the
purpose of illustrating better that the strip u, has an enlarged portion. Upon the
trapezoidal projections t, are slipped and held trapezoidal tubes v, so that when wire
is wound in the usual way, it will be held effectually away from the metallic part
of the armature.
On the interior of the armature are pieces of mica insulating sheets j, exactly like
that shown in Figure 4. The trapezoidal tubes v, and the circular tube p, may be
held to the heads by shellac or varnish. Also varnish may be applied between the
heads a, m, and T, and the insulating covering of armature shown in Figure 13.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the sanie is to be performed, I declare that what I
claim is:
1. An annular disc for insulating armature head consisting of lamina of annular
discs each of which consists of the combination of concentric rings formed of mica,
with their edges overlapping and cemented together and a ring of mica scales
overlapping and cemented to one another and to said first named rings.
2. A disc for insulating armature heads, consisting of concentric rings of mica
scales, radiating from the centre, overlapping and cemented together at their
edges.
:
3. A disc for insulating armature heads, consisting of concentric rings of mica
scales, radiating from the centre, overlapping and cemented together at their
edges, and a flange formed at the periphery of said disc.
4. An armature consisting of the combination of a ring core supported upon
radial spokes, a flanged annular mica disc, applied to each end of said ring, the
flanges passing to the interior and exterior of said ring, curved mica sheets applied
to the interior of said ring between the spokes, slotted mica insulators h, applied
in grooves which are provided on the exterior of said armature, and projecting from
said grooves at the ends.
5. An armature consisting of the combination of a ring core supported upon
radial spokes, a flanged annular mica disc, applied to each end of said ring, the
flanges passing to the interior and exterior of said ring, curved mica sheets applied
to the interior of said ring, between the spokes, slotted mica insulators applied in
grooves which are provided on the exterior of said armature and projecting from
said grooves at the ends, each of the said mica insulators being formed of mica
scales cemented together with overlapping edges cemented together.
6. An armature consisting of the combination of an iron ribbon u, having a
wider portion u', all wound in convolutions whereby projections t, are formed by the
portion u, a flanged annular mica disc r, having perforations s, through which
pass said projections t, the flanges of the disc lapping over the interior and exterior
of the ring, insulating mica tubes v, fitted upon and cemented to the projections t,
curved insulating mica sheets j, applied to the interior of the ring between the
spokes thereof, and a cylindrical mica covering applied to the exterior of the ring.
7. An armature consisting of the combination of a ring having end projections,
circularly arranged, flanged annular mica discs applied to the ring and having
perforations through which pass said projections, the flanges of the discs lapping
over or under the interior and exterior of the ring, insulating mica tubes fitted upon
the projections and curved insulating mica sheets applied repectively to the inner
and outer surfaces of the ring.
8. An armature consisting of the combination of a laminated iron ring, annular
mica discs applied to the ends of the ring, a mica covering fitting over or under

page_text: the outer surface of the ring, and flanges on said discs lapping over the exterior
and interior surfaces of the ring.
9. An armature consisting of the combination of an iron ring, annular mica discs
applied to the ends of the ring, a mica covering fitting over the outer surface of the
ring, and flanges on said discs lapping over the exterior and interior surfaces of
the ring, the flanged mica discs being made in sections and fastened together with
overlapped joints.
10. An armature consisting of the combination of an iron ring core, and a
covering for the same, consisting of sheets of mica cemented together with
overlapping edges.
11. The combination of an armature core and an insulator covering the same,
consisting of sheets of mica cemented together with overlapping edges.
12. An insulator for armature heads consisting of an annular disc, having flanges
on one or both peripheries and consisting of alternately arranged and parallel layers
respectively of cement and mica sheets with overlapping edges.
13. An insulator for armature heads consisting of an annular disc, having
flanges on one or both peripheries and consisting of alternately arranged and
parallel layers respectively of cement and mica sheets with overlapping edges, the
disc being provided with perforations.
Dated this 13th day of November 1893.
HUGHES, SON & Co.,
38, Chancery Lane, W.C., Agents for the Applicant.