IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
Year: 1883

page_text: LETTERS PATENT to Sebastian Ziani de Ferranti of N° 5 Stanwick Road West
Kensington in the County of Middlesex Electrician for an Invention of
PROVISIONAL SPECIFICATION left by the said Sebastian Ziani de Ferranti
at the Office of the Commissioners of Patents on the 29th October 1883.
SEBASTIAN ZIANI DE FERRANTI of N° 5 Stanwick Road West Kensington in
the County of Middlesex Electrician "IMPROVEMENTS IN DYNAMO-ELECTRIC
MACHINES
This invention has for its object improvements in dynamo electric machines.
I wind the wire upon the field magnets in planes parallel to the axis of the
armature or wheel thus the wire may pass first along the field magnet over the
upper side of the armature then down past the end of the armature returning
again underneath the armature and so on, the winding being always parallel to the
axis and in large convolutions completely encircling the armature. At the two
ends the winding will deviate from the direct course in order to admit of the
passage of the axis and if necessary also to allow the wheel or armature to be
readily inserted and withdrawn. In place of arranging the winding entirely in a
vertical plane some of the winding may be horizontal and other portions of it may
lie in planes variously inclined to the vertical but always parallel to the axis of the
armature which is assumed to be horizontal.
For alternate current machines I construct the field magnets in the following
manner. The magnets here take the form of two rings face to face with a narrow
space between them in which the wheel armature rotates. Each magnet is built
up of sections of iron fitting together to form a corrugated structure. The corru-
gations are radial and each ridge presented to the face of the armature represents a
magnetic pole and these poles are alternately North and South-Each section has
its own exciting coil wound around it and these coils are connected either in series
or in parallel circuit with the coils of the other adjacent magnets.

page_text: In some cases I form the field magnet as a cast iron ring having taper pole
pieces projecting from its face-Each pole, piece is thick at the root where it joins
the ring and smaller at the point which is adjacent to the armature. Each pole
piece has its own coil which is tapered internally to fit it; externally the coil is of
the same dimensions from end to end-By this arrangement a greater mass of
metal is provided in the core to transmit to the poles the effect of the more distant
coils.
Also by the several means of winding the field magnets which I have described
the coils on the magnets are brought into position to exercise a more direct influence
on the armature coils.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Sebastian Ziani de Ferranti in the Patent Office on the 29th April
1884.
SEBASTIAN ZIANI DE FERRANTI of N° 5 Stanwick Road West Kensington in
the County of Middlesex Electrician "IMPROVEMENTS IN DYNAMO ELECTRIC
MACHINES
This invention has for its object improvements in dynamo electric machines.
I wind the wire upon the field magnets in planes parallel to the axis of the
armature or wheel; thus the wire may pass first along the field magnet over the
upper side of the armature then down past the end of the armature returning again
underneath the armature and so on the winding being always parallel to the axis
and in large convolutions completely encircling the armature. At the two ends the
winding will deviate from the direct course in order to admit of the passage of the
axis and if necessary also to allow the wheel or armature to be readily inserted and
withdrawn. In place of arranging the winding in a vertical plane it may be
horizontal or lie in planes variously inclined to the vertical but always parallel to
the axis of the armature.
For alternate current machines I construct the field magnets in the following
manner: The magnets here take the form of two rings face to face with a narrow
space between them in which the wheel armature rotates. Each magnet is built
up of sections of iron fitting together to form a corrugated structure. The corru-
gations are radial and each ridge presented to the face of the armature represents a
magnetic pole and these poles are alternately North and South. Each section has
its own exciting coil wound around it and these coils are connected either in series
or in parallel circuit with the coils of the other adjacent magnets.
By the several means of winding the field magnets which I have described the
coils on the magnets are brought into position to exercise a more direct influence on
the armature coils.
In order that my said invention may be most fully understood and readily carried
into effect I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS
Figure 1 is an elevation partly in section of a dynamo electric machine constructed
in accordance with my invention.
Figure 2 is a plan of the same with the upper part and also the armature removed
and with the field magnet coils in section.
Figure 3 is an end elevation one half in section of the same machine.
AA is the frame of the machine and together with the coils or windings of wire
BB it also forms the field magnet. The position of the armature is indicated by
dotted lines at C. O. and D is the axis of the armature.
The armature is of the ordinary description and it is wound in an usual manner
manner with insulated wire passing around it over and under in planes parallel to
the axis.
The winding of the field magnets is also parallel to the axis except in so far it
deviates from the direction in order to admit of the more easy insertion of the
armature C.
As represented in the drawing the winding is made to open out at the two ends
leaving circular apertures.
Each convolution of the winding passes over the armature from side to side of
the machine in the direction parallel to the axis then deviates and by a semi-circular

page_text: course passes to the under side of the axis; then it returns from beneath the axis
and parallel thereto from one end of the machine to the other and finally again
deviates and by a semi-circular course rises again to the top and so the winding is
carried out.
The coils are divided into two sections as seen in Figure 2-in one section these t
semi-circular deviations are at the front and on the other at the back of the
machine.
In Figure 3 the semi-circular portion of the winding is represented only on one
side of the figure but it should appear similarly upon the other side.
Figure 4 is a transverse section similar to Figure 3 but showing another form of 1
iron frame serving also as field magnet.
It is not necessary that the plane of the winding should be vertical so long as it
is in the main in a plane parallel to the axis.
Arrangements may be made which will avoid the necessity for so large a deviation
as the drawing shows from the plane of the axis at the two ends.
By winding the field magnets in the manner described above the inner portion
of the winding is able to exercise a direct and effective inductive action upon the
conductor with which the armature is wound. The outer part of the winding
which is remote from the armature operates more directly to magnetise the iron
frame and so indirectly for the most part it influences the armature.
Figure 5 is a vertical section of an alternate current machine constructed in
accordance with my Invention.
A, A, are the main cast iron frames, upon which are the bearings for the axis of
the armature, and which also carry and magnetically connect the pole pieces B, B,
these are held on by bolts A³, A!, These pole pieces are peculiar in form, and the
winding around them is also peculiar; they form a pair of zig-zag or corrugated
ring field magnets.
Figure 6 is a front view of one of the frames A with its pole pieces B, B, upon it
but without the winding of insulated wire.
Figure 7 is an elevation partly in section showing these pole pieces with their
windings as they appear when looking at it edgeways, or relatively to Figure 6
from a point in the plane of the paper exterior to the circle.
Figure 8 is also an edge view, but of the inner side; it represents Figure 6 as
seen from a point in the plane of the paper and within the circle.
The Figures 7 and 8 are not foreshortened, the appearance therefore is that which
Figure 6 would represent if divided on one side and laid out straight.
Each pole piece B is held down to the inclined face of A by bolts A¹ A¹ and
these hold it in a position inclining away from the face to which it is attached.
Its upper end meets the upper end of the next pole piece, which is similarly held
and similarly inclined, but at an opposite angle, so the pole pieces fixed upon the
surface of A, form a series of radial undulations or corrugations.
Before the pole pieces are thus fixed they receive their windings of insulated
wire each pole piece is separately wound and forms a separate bobbin. The bobbins
when packed together form a compact mass, as represented by the Figures 7 and 8.
The bobbins are so coupled that when the machine is at work an electric current or
currents circulates in their coils in such manner as to render the exposed extremities
of the pieces B alternately in pairs, north poles and south poles, as indicated by the
letters N and S in the Figures 6 and 7.
Field magnets thus constructed and wound are intended especially to be employed
in connection with armatures wound in zigzag in the manner described in the
specifications of former patents granted to me but they may be otherwise wound.
Figure 9 is a horizontal section of a machine having similar field magnets to that
described by Figures 5, 6, 7 and 8 but arranged to work with a Gramme armature
for the production of a continuous current by the aid of a commutator. Each field
magnet in this case possesses four pairs of poles, two north poles, diametrically
opposite, and two south poles equidistant between the-north poles.

page_text: Figure 10 is a front elevation of one of the sets of pole pieces belonging to one of
these field magnets.
Figure 11 is an edge view of the same, drawn in the manner already described
in respect to Figure 7.
Figure 12 is a similar view of the pole pieces as they appear looked at from within
the circle; this figure corresponds to the Figure 8 of the arrangement previously
described.
G in Figure 9 is the Gramme armature of the ordinary sort, G¹ is its axis and
G2 the commutator.
By winding field magnets as described in respect to Figures 5 to 12 the windings
of the adjacent core cooperate in unison and the one reinforces the action of the
other; the arrangement is therefore very favorable to obtaining an efficient
magnetization of the cores.
Having thus described the nature of my said Invention and the manner of
performing the same, I would have it understood that I claim-
First. The method of winding field magnets described in respect to Figures 1, 2,
3 and 4, that is to say, winding the same with coils parallel to the axis of the
armature and passing alternately over and under it, or on one side and the other,
substantially as herein described.
Second. The method of arranging and winding the pole pieces of field magnets;
the said pole pieces each wound with its own bobbin being set in inclined positions
so as to form an undulating ring structure as described in respect to Figures from 5
to 12 of the annexed drawing.
Third. The construction of dynamo machines substantially as herein described
and represented in the annexed drawing.
In witness whereof I the said Sebastian Ziani de Ferranti have hereunto set
my hand and seal this Twenty ninth day of April in the year of our Lord One
thousand eight hundred and eighty four.
SZ DE FERRANTI
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FERRANTI (10)