Improvements in Dynamo Electrical Machines.
Year: 1888

page_text: Date of Application, 23rd Oct., 1888
Complete Specification Left, 23rd Aug., 1889-Accepted, 19th Oct., 1889
PROVISIONAL SPECIFICATION.
Improvements in Dynamo Electrical Machines.
I, SEBASTIAN ZIANI DE FERRANTI of 120 Fellowes Road Hampstead in the
County of Middlesex Electrician do hereby declare the nature of this invention to bo
as follows:-
The object of my invention is to construct dynamo electrical machines in such
manner that the revolving armature and fixed field magnets can be quickly got at for
cleaning or repairs.
In alternate current machines in which the armature revolves between two circles of
fixed magnets placed one on either side of it-I make the bearings for the armature
axle quite independent of the frames which carry the two circles of fixed field magnets
and I make each of these frames capable of being shifted away from the armature in
a direction parallel with the armature axle. The bed on which the frames are sup-
ported being formed with extensions for the frames to be supported on when they are
so drawn back away from the armature.
In machines of large dimensions I form the frames to rest at their two opposite
sides on the surface of beds which are approximately on a level with the armature
axle and are parallel with it, the lower half of each frame being then received in a pit
between the two beds. To shift the frames towards or away from one another
screw gear or endless chains or hydraulic cylinders or other mechanism may be
used.
In continuous current machines wherein an armature revolves between a pair of
magnet poles I similarly form the bed of the machine in such a manner that each of
the pole pieces can be slidden back along the bed away from the armature. When the
pole pieces are uppermost away from the bed the bed itself forms an iron connection
between the rear extremities of the two pole pieces. When the magnets are inverted
and the pole pieces are towards the bed I make the two pole pieces to rest in shoes of
bronze or like non-magnetic metal which are capable of being slidden to and fro upon
the bed and the rear extremities of the two pole pieces I make to butt together when
in working position and so complete the magnetic circuit above the coils.
Dated this 23rd day of October 1888.
S. Z. DE FERRANTI.
COMPLETE SPECIFICATION.
Improvements in Dynamo Electrical Machines.
I, SEBASTIAN ZIANI DE FERRANTI, of 120 Fellowes 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 :-
The object of my invention is to construct dynamo electrical machines in such
manner that the revolving armature and fixed field magnets can be quickly got at for
cleaning or repairs.
In alternate current machines in which the armature revolves between two circles
of fixed magnets placed one on either side of it-I make the bearings for the armature
axle quite independent of the frames which carry the two circles of fixed field magnets
and I make each of these frames capable of being shifted away from the armature in
a direction parallel with the armature axle. The bed on which the frames are sup-
ported being formed with extensions for the frames to be supported on when they are
so drawn back away from the armature.

page_text: In machines of large dimensions I form the frames to rest at their two opposite
sides on the surface of beds which are approximately on a level with the armature
axle and are parallel with it the lower half of each frame being then received in a pit
between the two beds. To shift the frames towards or away from one another
screw gear or endless chains or hydraulic cylinders or other mechanism may be
used.
In continuous current machines wherein an armature revolves between a pair of
magnet poles I similarly form the bed of the machine in such a manner that each of
the pole pieces can be slidden back along the bed away from the armature. When
the pole pieces are uppermost away from the bed the bed itself forms an iron con-
nection between the rear extremities of the two pole pieces. When the magnets are
inverted and the pole pieces are towards the bed I make the two pole pieces to rest in
shoes of bronze or like non-magnetic metal which are capable of being slidden to
and fro upon the bed and the rear extremities of the two pole pieces I make to
butt together when in working position and so complete the magnetic circuit above
the coils.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawings hereunto annexed.
Figure 1 is a plan showing the general arrangement of a set of alternate current
dynamos to which my present invention is applied. The scale of this figure is
about one eighth of an inch to a foot so that these dynamos are of very large
dimensions.
Figure 2 is a half elevation partly in section of one of these dynamos.
Figure 3 is a transverse vertical section of the same.
Figure 4 is a half front elevation partly in section of the two ring frames which
carry the field magnets.
Figure 5 is a side elevation of the two ring frames.
Figure 6 is an end elevation of a continuous current dynamo to which my inven-
tion is applied.
Figure 7 is a side elevation of the same.
Figure 8 is an end elevation of a continuous current dynamo of another form to
which also my invention is applied:
Figure 9 is a plan of the last mentioned dynamo with the field magnet removed.
In Figures 1 to 5 a is the axis of the armature, it is carried in bearings a al and
it has cranks a² at its cuds. Each crank is driven by a steam engine the cylinders a³
of which are vertically over the crank. bare the ring frames in which the field
magnets are carried-they are cast in sections and bolted together internally as the
drawing shows. cc are the bed frames of the engines and d d are the beds on which
the ring frames & stand.
The beds d d are firmly bolted to the bed frames cc which they serve to connect
and together they form the main bed frame of the structure.
are the soft
iron cores of the field magnets; the ring frames bb are cast upon them. The
frames bb when in their working positions abut face to face and a narrow space is
left between the ends of the cores 61 in the two rings. This space is just sufficient
for the passage of the conductor a carried by the armature and in this conductor
alternating currents are generated as it is carried round between the magnetised
cores b. The ring frames have lugs on their undersides in which are nuts
engaged with screw threads on axes e e. Each axis e is held in a bearing on the bed d
and it has upon it a right and a left screw thread, and these are engaged with the
nuts on the two frames forming a pair. Hence when the axis is turned the screws
serve to separate or to draw together the two frames: the frames sliding upon smooth
faces upon their beds d d. Each axis e also carries a worm wheel e¹ and with this a
worm on a shaft engages. The shaft is driven through gear wheels by a
small steam engine. There are two worms upon the shaft ; these worms turn

page_text: the two right and left screws e which act simultaneously to move the pair of ring
frames b.
Adjusting screws should be provided to set the nuts in the lugs 62 exactly so that
the right and left screws may place the ring-frames correctly and then the attraction
of the magnet cores holds them very firmly. There are no bolts either to connect the
ring frames or to secure them to the bed frame. Hence when an examination is to
be made there are no parts to be removed. So by carrying the field magnets in
frames separate from the frames which carry the engines and the armature axis and
by arranging these magnet frames to stand upon beds firmly fixed to or forming part
of the main frames and to be moveable by sliding upon these beds 1 am able to obtain
ready access to the electrically operative parts.
In Figures 6 and 7 g is the bed of the machine and electrically it also forms part of
the field magnet of which hh are the pole pieces and ¹¹ the windings. is the
armature and its axis. k is the commutator. The axis is carried by the
standards g g rising from the bed. The pole pieces are provided with feet h
which stand upon surfaces on the bed g and clamping nuts are provided to hold
them. If the inachine be a small one no gear is necessary to move the pole pieces
but when it is of considerable dimensions it is convenient to provide screw gear as
shown and which is similar to that already described except that the axes e on
which are the right and left screws are turned directly by a lever applied at the
end.
In Figures 8 and 9 g is the bed and gl standards carrying. the axis of the
armature i k is the commutator. h are the pole pieces, the windings and h² h²
parts of the field magnet which when in their working positions abut together and
establish complete magnetic connection between the two pole pieces.
11 are feet of bronze or other non-magnetic metal separating the pole pieces from
the base so that the magnetic lines of force are compelled to traverse the armature.
e is a right and left hand screw operating as already described to separate the pole
pieces and to draw these together.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. In an alternate current dynamo electric machine substantially as described
mounting the field magnets on two frames, independent of the main frame which
carries the bearings of the axis of the armature; such field magnet frames resting
upon the main frame and being capable of sliding thereon in a direction parallel to
the armature axle so that the said field magnet frames may be drawn apart to give ready
access to the armature and magnets and afterwards brought together again with the
magnets truly in their working positions as herein set forth.
2. In an alternate current dynamo electric machine substantially as described
mounting the field magnets on two frames independent of the main frame but resting
upon it and projecting down below the supporting surfaces on the main frame into a
pit beneath as herein set forth.
3. In an alternate current dynamo electric machine substantially as described
mounting the field magnets on two frames independent of the main frame but resting
thereon and connected by screw gear by means of which they can be separated to
give ready access to the armature and magnets and afterwards brought together
again with the magnets truly in their working positions as herein set forth.
4. In a continious current dynamo electric machine substantially as described
mounting the pole pieces of the field magnet upon the bed of the machine so that
they are able to slide upon surfaces thereon and to be drawn apart to give ready
access to the armature and-afterwards brought together again truly in their working
positions as herein set forth.
5. In a continuous current dynamo electric machine substantially as described
making the field magnet in two parts magnetically insulated from the frame of

page_text: the machine but supported by surfaces thereon so that they may be drawn apart
to give ready access to the armature and brought together again into close magnetic
connection and truly in their working positions as herein set forth.
6. In a continuous current dynamo electric machine substantially as described
making the field magnet or its pole pieces independent of the main frame but sup-
ported thereon and in parts connected by screw gear by which the parts can be
separated to give ready access to the armature, and afterwards brought together again
truly to their working positions as herein set forth.
7. In an alternate current dynamo electric machine substantially as described
mounting the field magnets on two frames dependent upon gravity and the mutual
attraction of the magnets for their maintenance in position when at work as herein set
forth.
8. In a continuance current dynamo electric machine substantially as described
making the field magnet in parts dependent upon gravity and the mutual attraction
of the parts for their maintenance in position when at work as herein set forth.
9. Dynamo-electric machines substantially as described and represented by the
annexed drawings.
1000
CARPMAEL & Co.,
Agents.