Improvements in the Manufacture of Dynamo Electric Machines.
Year: 1891

page_text: Date of Application, 20th Jan., 1891
Complete Specification Left, 20th Nov., 1891-Accepted, 19th Jan., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Dynamo Electric Machines.
I, SEBASTIAN ZIANI DE FERRANTI, of 120 Fellows Road, Hampstead, in the
County of Middlesex, Electrician, do hereby declare the nature of this invention
to be as follows:-
In the manufacture of dynamo electric machines in which the wrought iron cores
of the fixed magnets are held in place by casting upon them at one of their ends a
cast iron frame so that their ends unite with the cast metal-I, in order to ensure
that the wrought iron cores shall be secured to the frame in correct positions, first
range them in place on the flat top of an iron bed which is placed at the bottom of
the mould within which the frame is to be cast and I fix them firmly in position to
this bed preferably by clamp bars placed across the top of the iron cores and by
bolts passed down through the clamp bars and through the bed. The sand mould
is then made up above the bed leaving so much of each wrought iron core as is to
be embedded in the cast iron frame projecting up above the sand. Afterwards
the bolts and clamp bars which retained the iron cores in position are removed so
that after the casting has been made they may be free to slide upon the bed as the
casting contracts. The completion of the formation of the mould is then proceeded
with.
In some cases it is desirable that the ends of the wrought iron cores which are to
project outwards from the cast frame should be kept cool during the time of casting
to prevent the ends which are embedded in the casting from being too highly
heated by the molten metal surrounding them and ensure that when the metal cast
around them cools they shall be securely gripped and held by it. To do this 1
form around the ends of the cores which are embedded in the sand of the mould
a channel through which a current of air or like fluid can be forced during the time
that the frame is being cast upon them. To form this air channel I place upon
the bed which supports the wrought iron cores before ramming in sand above it, a
hollow arched casing through the top of which holes are formed for the wrought
iron cores to project through and ram in the sand at the sides and over the top of
this casing.
In place also of forming each magnet pole piece of one forging of wrought iron
I make it up of a number of plates placed together face to face. These plates may
be cut economically from one large sheet without waste by first cutting the sheet
into lengths each adapted for being again divided into two-one say a narrow one
of the size required for the portion of a pole piece which is nearest to the centre of
the circle in which the pole pieces are to be ranged the other adapted for the
outermost portion of the pole piece. Similarly other lengths may be divided into
two portions adapted for forming two other parts of a pole piece. In order that
each plate may be the more securely held in the frame which is cast on to the ends
of the pole pieces I make the end of each plate which is to be embedded in the
metal with dovetail or other extensions from it or with notches cut out from its
edges or with holes formed through them for the metal to run into.
To hold together the several plates which are to form a pole piece side by side
during the time that their edges are being tooled and the built up pole pieces.
brought accurately to form and also during the time that the pole pieces are having
the mould for the cast iron frame formed around them I cover the sides of each
plate with paste, paint, varnish or adhesive material before putting the plates
together and then hold them all together securely in a screw clamp frame and

page_text: bake them in a heated oven.
one block.
In this way they are all solidly united together into
CARPMAEL & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Dynamo Electric Machines.
I, SEBASTIAN ZIANI DE FERRANTI, of 120 Fellows Road, Hampstead in the
County of Middlesex, 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 manufacture of dynamo electric machines in which the wrought iron
cores of the fixed magnets are held in place by casting upon them at one of their
ends a cast iron frame so that their ends unite with the cast metal I in order to
ensure that the wrought iron cores shall be secured to the frame in correct positions,
first range them in place on the flat top of an iron bed which is placed at the
bottom of the mould within which the frame is to be cast and I fix them firmly in
position to this bed preferably by clamp bars placed across the top of the iron
cores and by bolts passed down through the clamp bars and through the bed. The
sand mould is then made up above the bed leaving so much of each wrought iron
core as is to be embedded in the cast iron frame, projecting up above the sand.
Afterwards the bolts and clamp bars which retained the iron cores in position are
removed so that after the casting has been made they may be free to slide upon the
bed as the casting contracts. The completion of the formation of the mould is then
proceeded with.
Figure 1 is a longitudinal section of a portion of a mould formed in this manner.
Figure 2 is a cross section of the same.
A is an iron bed plate. B B are some of the iron cores. C is a clamp bar
placed across the top of these cores. DD are long bolts screwing into the bed
plate and holding down the clamp bar. E is a box within which the sand mould is
formed. Before putting on the top cover of the mould box the bolts D and bar C
are removed as before stated and the holes left by the removal of the bolts are
then filled in with sand and the casting of the bed within the mould is proceeded
with.
In some cases it is desirable that the ends of the wrought iron cores which are to
project outwards from the cast frame should be kept cool during the time of casting
to prevent the ends which are embedded in the casting from being too highly
heated by the molten metal surrounding them and ensure that when the metal cast
around them cools they shall be securely gripped and held by it. To do this I
form around the ends of the cores which are embedded in the sand of the mould a
channel through which a current of air or like fluid can be forced during the
time that the frame is being cast upon them. To form this air channel I place
upon the bed which supports the wrought iron cores before ramming in sand above
it a hollow arched casing through the top of which holes are formed for the
wrought iron cores to project through and ram in the sand at the sides and over the
top of this casing.
Figure 3 is a longitudinal section of a portion of a mould formed in this manner.
Figure 4 is a cross section of the same.
A is the iron bed plate to which the cores B are securely held by the clamp
bar C and bolts D whilst the mould is being formed within the box E. F is an
arched casing placed within the box upon the bed A. It may either be in one
piece with the box or separate from it.
G is an inlet at one end of the box through which air or other fluid may be
supplied to the casing F. At the other end of the box a similar outlet is provided,

page_text: The holes in the top of the casing down through which the cores B pass would
be made of sufficient size to allow of slight movement of the cores as the metal
casting is contracting in cooling.
In place also of forming each magnet pole piece of one forging of wrought iron
I make it up of a number of plates placed together face to face. These plates may
be cut economically from one large sheet without waste by first cutting the sheet
into lengths each adapted for being again divided into two-one say a narrow one
of the size required for the portion of a pole piece which is nearest to the centre of
the circle in which the pole pieces are to be ranged the other adapted for the
outermost portion of the pole piece. Similarly other lengths may be divided into
two portions adapted for forming two other parts of a pole piece. In order that
each plate may be the more securely held in the frame which is cast on to the ends
of the pole pieces I make the end of each plate which is to be embedded in the
metal with dovetail or other extensions from it or with notches cut out from its
edges or with holes formed through them for the metal to run into.
Figure 5 is a face view of a portion of a cast iron frame with magnet pole pieces
formed in this manner projecting out from it.
Figure 6 is a cross section of the same.
Figure 7 is a face view and Figure 8 an edge view of one form to which the
plates of which the pole pieces are formed may be cut.
Figures 9 and 10 shew similar views of another form of plate.
The plates in addition to or instead of being made dovetail at their ends as shown
in Figures 7 to 10 may also be bent sidewise half in one direction and half in the
opposite direction so as to form a dovetail end to the pole piece as shewn at
Figure 6.
To hold together the several plates which are to form a pole piece side by side
during the time that their edges are being tooled and the built up pole pieces
brought accurately to form and also during the time that the pole pieces are having
the mould for the cast iron frame formed around them I cover the sides of each
plate with paste, paint, varnish or adhesive material before putting the plates
together and then hold them all together securely in a screw clamp frame and bake
them in a heated oven. In this way they are all solidly united together into one
block.
Figures 11 and 12 shew clamps holding together a number of plates in this way
whilst they are being baked-the cross lines through the plates held in these clamps
show how each plate may be in two or more divisions.
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. The manufacture of a cast iron frame with wrought iron magnet cores standing
out from it by first securing the cores accurately in position on an iron bed
preferably by a clamp bar and bolts then making up the sand mould upon the bed
and afterwards releasing the cores from the bed before filling the mould with metal
substantially as described.
.
2. In the manufacture of a cast iron frame with wrought iron cores standing out
from it the cooling of the cores after the frame has been cast on to one of their ends
by a current of air forced past the ends which stand out from the frame substantially
as described whilst the frame is contracting in cooling.
3. The manufacture of a cast iron frame with wrought iron magnet cores standing
out from it by placing above the bed on which the mould is to be formed an arched
casing then passing the ends of magnet cores down through holes in the top of this
casing and securing them to the bed. Afterwards when the mould has been formed
around the exterior of the casing releasing the cores and when the mould is
complete and the mould has been filled with metal forcing air or other fluid through
the chamber keep the ends of the cores cool substantially as described.
4. Making each of the magnet cores of a number of plates placed together face to

page_text: fuce and casting on to such built up cores a cast iron framing substantially as
described.
5. Forming the plates of which each pole piece is made up with projections or
recesses on the parts on to which the metal frame is. to be cast so that the plates
may be held the more securely in the casting substantially as described.
6. Securing together the several plates which are to form a pole piece sub-
stantially as herein described and then tooling the built up pole piece accurately to
form before forming around it the mould within which the frame in which it is to
be held is cast.
Dated this 20th day of November 1891.
CARPMAEL & Co.,
Agents.