Improvements in Continuous Current Dynamo Electric Generators and Motors.
Year: 1896

page_text: Date of Application, 8th Aug., 1896
Complete Specification Left, 8th May, 1897-Accepted, 31st July, 1897
PROVISIONAL SPECIFICATION.
Improvements in Continuous Current Dynamo Electric Generators
and Motors.
SEBASTIAN ZIANI DE FERRANTI, 27 Charterhouse Square, in the County of London;
Engineer and Electrician, do hereby declare the nature of this invention to be as
follows:-
This invention has for its object improvements in continuous-current dynamo
electric generators or motors and is especially applicable to such machines as require for
the efficient working, a considerable mass in the revolving parts in order to attain
regularity of speed with varying powers.
In the forms of generator usually manufactured, the revolving part of the machine
is the armature, which forms only a comparatively small portion of the total weight
of the machine, while the bedplate on which the machine stands together with the
magnets which are used for inducing currents in the armature, form the major
portion of the weight of the machinery.
The machines made according to my invention are particularly suitable for use
where they are used as generators for producing currents, and where these generators
are coupled direct to the shaft. of steam engines or other motors.
I
According to my invention, I form the armature in the ordinary way, building it
up of a series of plates of iron or steel, mounted upon a carrying device, or spider,
and this spider I support on a bracket, which I preferably bolt direct on to the
bedplate of the engine or other motor, and I make this bracket hollow, so that I can
pass through it the shaft or continuation of the shaft of the engine or motor, and-to
this shaft attach by suitable means a boss for the purpose of carrying or supporting
the magnets of the machine, which I revolve about the outside of the armature.
form the magnets on the inner surface of a ring of steel or iron, these projections
forming the magnet bars, being either cast on to the inner surface of the ring, or
boltedon to it, and on to these projections I put coils of wire for magnetising them.
The said ring forms the yoke for connecting the ends of the magnets remote from the
armature in the ordinary way, and I extend this ring on either side so as to project
beyond the magnet coils, and I then carry down flanges parallel to the axis of the
magnet bars which are attached to the inner surface of the ring, and I bore out these
flanges and the magnet bars to one diameter.
I forin the poles on the inner surface of an iron or steel ring, or I form them
separately, and unite them either by strips of iron or steel, or by strips of suitable
non-magnetic metal, and on to either end of this ring, I attach cylindrical boxes of
brass or other non-magnetic metal, which being turned on the outside to the same
diameter as the outside of this pole ring, forms one continuous surface, and I push
this pole ring together with the cylindrical boxes on either end into the space which
I have formed by boring out the magnet bars and flanges at either end of the yoke,
so that when in position the poles formed in this ring are opposite to, and close to,
the ends of the magnet bars, and the cylindrical non-magnetic boxes on either end of
the ring fit closely into the flanges at either end of the yoke, so that by this

page_text: construction I entirely enclose the coils of wire, on the magnet, in the metal
case.
In some cases I subsequently prefer to cast up the space so formed, which surrounds
the magnet coils, with a mixture of sulphur and glass or some other suitable material,
so as to completely exclude moisture and to firmly fix the coils in position so that
there is no risk of there being damaged by mechanical movements.
In some cases I form subsidiary polepieces on the ring between the main polepieces
already described, on to which I place windings of copper carrying the current
generated in the armature, becoming thereby magnetised, and I use the magnetic flux
so produced for reversing the current in the coils in the armature as they undergo
commutation in the ordinary manner.
In some cases I prefer to form the magnet ring together with the pole ring in two
or more pieces divided parallel to the axis, in order that they may be readily removed
from the outside of the armature if I desire to inspect this, and in that case in
addition to bolting the magnet ring to the boss on the shaft, which I have already
described, I surround the ring entirely by one or more steel hoops or rings, which
being turned on the inner surface to a conical shape, fit closely on the conical surfaces
turned on the outer surface of the magnet ring, and being forced on to the magnet
ring by suitable bolts or screws, hold the several portions of the magnet ring firmly
together.
In continuous current machinery I collect the current from the armature by means
of brushes, which revolve with the magnet ring, pressing on to a commutator which
is attached to the armature, and I carry these brushes in rings of brass or other
suitable metals, which are supported on studs carried from the magnet ring by
pockets into which they are fastened by means of a mixture of sulphur and glass or
other suitable compound, and I likewise carry separate rings, where necessary, for
supplying current to the windings on the magnet bars, and from the rings which
carry the brushes I collect the current by means of suitable brushes carried on the
brackets which are attached to the foundations of the machine, or other suitable
stationary part.
Dated this 9th day of turust 1906
COMPLETE SPECIFICATION.
Improvements in Continuous Current Dynamo Electric Generators
and Motors.
I, SEBASTIAN ZIANI DE FERRANTI, Hollinwood in the County of Lancaster,
Engineer and Electrician, late of Charterhouse Square in the County of London, 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-
This invention has for its object improvements in continuous-current dynamo
electric generators and motors, and is specially applicable to such machines as require
for efficient working a considerable mass in the revolving parts in order to attain
regularity in speed with varying powers. In the forms of generators usually
manufactured, the revolving part of the machine is the armature which forms only a
comparatively small portion of the total weight of the machine, while the bedplate
on which the machine stands, together with the magnets which are used for inducing
currents in the armature, form the major portion of the weight of the machinery.
The machines according to my invention are particularly suitable for use where they
are used as generators for producing currents, and where these generators are coupled
direct to the shafts of steam engines or other motors.

page_text: In order that my invention may be better understood,
I will now proceed to describe it with reference to the accompanying drawings,
reference being had to the letters and figures marked thereon, like letters referring to
like parts in the several figures.
Fig. 1., is a sectional elevation through a machine made according to my invention.
Fig. 2., is a part sectional elevation of the machine.
Fig. 3., is a cross-section through a portion of the machine.
Fig. 4., is a section through part of the magnet ring.
According to my invention, I form the armature (a) in Figs. 1 2 & 3 by building
up a series of plates of iron or steel, in the ordinary way, mounted on a spider or
carrying device (b). This spider I bolt, on a bracket (c) which I preferably bolt
direct on to the bedplate (d) of the engine or other motor or a projection from it, and
I make this bracket (c) hollow so that I can pass through it the shaft or continuation
of the shaft of the engine or motor, and by ineans of a boss (f) I support from the
shaft the magnet ring (9) which I revolve round the outside of the armature (a).
On the inner surface of the magnet ring (g) I form magnet bars (h) either by casting
them on to the inner surface of the ring or bolting them on to it, and on these magnet
bars (A) I put coils of wire () for magnetising them. The said ring (g) forms the
yoke for connecting the ends of the magnet bars remote from the armature in the
ordinary way, and I extend this ring (g) on either side beyond the magnet coils, and I
carry them down and form flanges () & (k,) parallel to the axis of the magnet bars
which are attached to the inner surface of the ring, and I bore out these
flanges (k) & (k,) to the same diameter as the magnet bars (4). I form the pole-
pieces (1) on the inner surface of the ring (m) of iron or steel (as described in Letters
Patent granted to me on April 2nd, 1896, and numbered 7195) or I may unite them
either by strips of iron or steel or by strips of suitable nonmagnetic metal, and 'I may
wind coils of wire or other suitable conductor on these poles as described in the
above mentioned Letters Patent, and on to the ends of this ring (m) I attach cylindrical
boxes () of brass or other suitable non-magnetic metal in which I enclose the
end-windings of the coils above mentioned, which being turned on the outside to the
same diameter as the outside of the ring (m) forms one continuous surface with it, and I
push this ring (m) together with the cylindrical boxes (a) on either end of it into the
space which I have formed by boring out the magnet bars (h), and the flanges (k) & (k)
at either end of the yoke so that when they are in position shewn in the
drawings No. 1, 2 & 3, the polepieces (1) formned on the ring (m) are opposite to and close
to the ends of the magnet bars (4) as shewn in Fig. 3, and the cylindrical nonmagnetic
boxes (a) on either end of the ring (m) fit closely into the flanges (k) & (k,) at either
end of the yoke, so that by this construction I entirely enclose the coils of wire (6)
which are situated on the magnets (h) in a metallic case formed by the
flanges () & (k,), the yoke (g), the pole ring (m), and the end boxes (n).
In some cases, I subsequently prefer to cast up the space (o) so formed which
surrounds the magnet coils with a mixture of sulphur and ground glass or other
suitable material, so as to completely exclude moisture and to firmly fix the coils in
position so that there is no danger of their being dainaged by mechanical
movements.
In some cases, I form subsidiary polepieces (p) between the main polepieces
already described, on which I place windings of copper carrying the current
generated in the armature. The subsidiary polepieces (p) thereby become magnetised,
and I utilize the magnetic flux so produced for reversing the current in the coils of
the armature as they undergo commutation in the ordinary manner.
In some cases I prefer to form the magnet ring (g) carrying the magnet bars (h)
in two or more pieces divided parallel to the axis of the machine, in order that they
may be readily removed from the outside of the armature if I desire to inspect these,
and in that case, in addition to bolting the magnet ring (9) to the boss (), by means
of the bolts (7) in Fig. 2, I may surround the whole ring (g) by one or more steel
hoops or rings (r) which being turned on the inner surface to a conical shape fit on to
conical surfaces (e) turned on the outer surface of the magnet ring (g) and being

page_text: forced on to the magnet ring by suitable bolts or screws, hold the several portions
of the magnet ring (g) firmly together.
I collect current from the armature by means of brushes pressing on the commutator
(u) Figs. 1 & 2, and I carry these brushes in rings of brass or other suitable metal (v)
which are supported on studs (w) which I may carry from the pockets cast into the
boxes (n) on the magnet ring and being secured in position by means of a mixture of
sulphur and ground glass or other suitable compound, and I likewise carry a separate
ring or rings (x) for supplying current to the windings (i) on the magnet bars (h)
these rings being carried by studs (y) fixed in pockets attached to the flanges (₁)
and I make connection with these rings (v) & (x) by means of suitable brushes
carried on brackets which are attached to the foundations of the machine or other
suitable stationary part.
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. In a continuous current dynamo electric generator, the construction of a
machine having a stationary armature surrounded by a ring having magnet poles
formed on the inner surface of it with cylindrical projections and end flanges
substantially as described and illustrated in the accompanying drawings.
2. In a continuous current dynamo electric generator having a stationary armature
and revolving magnet ring with end projections and flanges in combination a ring of
poles fitted with cylindrical end boxes of nonmagnetic material which fit into the end
flanges of the magnet rings, substantially as described and illustrated in the
accompanying drawings:
3. In a continuous current dynamo electric generator having a stationary armature
and a revolving ring of magnets formed on the inner surface of the magnet ring fitted
with end projections and flanges and a pole ring provided with cylindrical end boxes
of nonmagnetic material, the use of nonmagnetic insulating cement for filling up the
spaces surrounding the magnet windings substantially as described.
4. In a continuous current dynamo electric generator having a stationary armature
and a revolving magnet ring, the use of rings supported by studs carried in pockets
in nonmagnetic cylindrical cases attached to the pole ring, for carrying brushes bearing
on the commutator and furnishing means of connection thereto substantially as
described and illustrated.
5. In a continuous current dynamo electric generator the carrying of a stationary
armature by means of a hollow bracket from the bedplate of an engine or other motor
or from projections from this bedplate substantially as described and illustrated.
6. In a continuous current dynamo electric generator, the method of holding the
several parts of the magnet ring together by means of coned rings substantially as
described and illustrated in Fig. 4.
7. In a continuous current dynaino electric generator the construction and arrange-
ment of the various parts as described and illustrated in the accompanying figures.
Dated this 7th day of May 1897
S. Z. DE FERRANTI.