Improvements in the Construction of Armatures for Alternators and such like Machines.
Year: 1896

page_text: COMPLETE SPECIFICATION.
Improvements in the Construction of Armatures for Alternators and
such like Machines.
We, HORACE FIELD PARSHALL, and THE BRITISH THOMSON-HOUSTON,
LIMITED, both of 38, Parliament Street, Westminster, in the County of London,
Electrical Engineers, 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 :-
Our invention relates to the construction of armatures for alternators and such
like machines and has for its object to so form the armature core as to enable the
coils to be previously formed, insulated and prepared, and then to be readily placed
in their permanent positions upon the core projections without bending or any
skilled labour, and thus to facilitate assemblage of parts and repairs in situ; also
to enable the ends of the wires of the coils to be easily and efficiently connected
together.
Heretofore the sides of the armature projections for receiving the coils have
been radial with the centre, and this necessitates a certain amount of bending and
forcing of the coils in order to get them on and off, which is not only difficult but
detrimental to the coils themselves.
According to our invention we form each of the stampings composing the
armature core with any required number of projections around its circumference,
those destined to receive the coils having their two sides parallel to each other and
to a radial line intersecting the mid width of each such projection. Between these
parallel-sided projections intervene an equal number of projections having their
adjacent sides parallel to the same radial line but otherwise of irregular form so
that a rectangular slot of suitable width is formed at either side of the coil-
carrying projections, and there are half as many coils in the armature as there
are projections on its circumference.
We will now fully describe our invention in reference to the accompanying
drawing in which
Fig. 1 is an elevation of a segment of one stamping showing three such parallel
sided projections and their slots formed according to our improvement; the
projection to the right is bare, on the central one a coil is shown placed in position
and secured, and on the left hand one a coil is shown in section.
Fig. 2 is a horizontal section on line 1-2 of Fig. 1 ;
Fig. 3 is a quadrant of one stamping;
Fig. 4 is an elevation and Fig. 5 a cross section showing our method of and
device for connecting the ends of the coils together.
A A A are the core projections destined to receive the coils C, and their
sides a a are parallel to each other and to the radial lines R R drawn through their
mid length. S S are the slots, also having parallel sides ab and rectangular
bases s, and both the projections A and the slots S between same are of any
required dimensions to suit and receive the coils; the intervening projections B B
are consequently of the irregular form shown and which will vary with the
dimensions of any armature. Opposite semi-dovetails D D are stamped out on
adjacent corners of the sides a and b of each projection A and B respectively and
adapted to receive wooden wedge pieces P P to secure the coils in position, and
Pare similar wooden laggings for the coils.
By this construction the coils C can be previously made upon a practically

page_text: rectangular former of the same width and depth as the projections A and slots S
and of the full length of any number of stainpings when assembled and bolted
together, and they can be easily slipped on to the projections A without bending
or force. In the previous making of the coils it is preferred to convex their ends
to sufficient extent to avoid sharp angles and corners and to insert wooden bearings
as shown at W, Fig. 2. The coils are all wound aliko following the armature
round in regular succession, and when placed in position they completely fill the
rectangular slots S as shown.
In connecting together the ends of the coil wires c c the simple device shown in
Figs. 1 and 4 is adopted, consisting of a pair of plates E E internally grooved as
at e to fit the wires c c, and these are clamped and held together by the
screws FF, the required tension of the wires being obtained by driving a
wooden cleat behind the plates if necessary, and any suitable insulation is
provided.
Armatures formed as above may be used for single or multiphase windings, but
in the latter case the projections A would be 14 times the number of field magnet
poles.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The mode of constructing aruntures in which the core stampings are all of
the form above set forth, the sides of each projection and of the slots on each side
thereof destined to receive a coil being parallel with one another and with a radial
line drawn through the mid length of the said projection, projections of irregular
form intervening so that when the stampings are assembled together previously
prepared coils may be placed in position and secured without bending, substantially
as described.
2. In armatures formed as above described the method of and device for
connecting together the ends of the coils as above set forth.
3. The improved construction of armatures for alternators and such like
machines as above described and illustrated in the drawings.
Dated this 27th day of February 1896.