IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES
Year: 1886

page_text: Date of Application, 24th July, 1886.
Complete Left, 5th Jan., 1887.
Complete Accepted, 1st Mar., 1887.
DECED
I JOSEPH PLATT HALL, of Gorse Bank, Werneth, Oldham, in the County of
Lancaster, Electrical Engineer, do hereby declare the nature of said Invention for
IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES to be as follows:-
My invention relates to improvements in dynamo machines and more particularly to
that class using the drum type of armature, of which type I prefer to use a modified
form of Gramme ring, and my improvements consist chiefly in novel constructions
and arrangements of the parts, my object being to cheapen the cost of manufacture
and at the same time to increase the efficiency of such machines.
In carrying out my Invention I cast the chief parts of the machine in one piece,
said parts embodying the bedplate, the magnet, with its keeper or yoke underneath
the bed and the magnet cores or legs terminating in the pole pieces above the bed and
also standards on the bed plate for carrying the pedestals in connection with the bearings
of the armature shaft; by this means I lessen the height of the pedestals and so
increase their stability.
To obviate the difficulty of winding the magnet I pass slips on to the cores over the
pole pieces on which suitable wire has been previously wound; to allow of my passing
these slips over the pole pieces I do not extend the pole pieces so as to embrace a
larger portion of the surface of the armature as is usually done in machines of this
class so as to control the field caused by the current circulating in the coils of the
armature but to achieve this end I bevel the edges of the polo pieces so as to increase
the air space between the armature core and the face of the pole piece at the places
where the wires on the armature first come into the field and similarly in the places
where the wires of the armature leave the field.
To insure the magnet saturating readily I maintain in the armature core and the
cores of the magnet sections of metal equal in proportion to their respective magnetic
capacity and so insuring that the magnetic induction is not impeded by any part of
the circuit becoming too rapidly saturated and further by making the armature core of
large diameter in comparison with those hitherto used, I greatly increase the surfaces
of metal exposed to one another on the armature core and on the faces of the pole
pieces of the magnets by which means I lessen considerably the magnetic resistance of
the air space.

page_text: The armature I prefer to construct on the Gramme system, building up the iron
core either of separate iron plates insulated from each other, or by winding on a coil
of suitably insulated iron wire or in any other manner. The conducting wire may be
wound on the core in the usual or any convenient way. For the sake of convenience
and cheapness of construction I prefer to make up the armature core as follows:-
:-
I key or otherwise secure the bosses of two brass or other diamagnetic metal spider
wheels or rings with arms suitably arranged on the armature shaft; these spider wheels
or rings are connected together by bolts over which is placed an insulating bush upon
which the iron plates rest, or the previously mentioned insulated iron wire is wound,
the whole being secured in position by tightening up the nuts on the bolts which then
hold all in place..
The above described construction permits the free admission of air to the interior of
the armature and in furtherance of this I secure when found desirable fins or vanes
on the previously mentioned arms of the aforesaid wheels or rings to exhaust and
draw fresh air through the interior of the armature so as to prevent the inside coils
from heating.

page_text: COMPLETE SPECIFICATION.
Improvements in Dynamo-electric Machines.
I JOSEPH PLATT HALL, of Gorse Bank, Werneth, Oldham, in the County of
Lancaster, Electrical Engineer, do hereby declare the nature of said Invention for
IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to improvements in dynamo machines and more particularly to
that class using the druni type of armature of which type I prefer to use a modified
form of Gramme ring and my Improvements consist chiofly in novel constructions and
arrangements of the parts, my object being to cheapen the cost of manufacture and at
the same time to increase the efficiency of such machines.
In order that my Improvements may be readily understood and carried into effect
I have annexed hereto three Sheets of Drawings which I will now proceed to describe
reference being had to the figures and letters marked thereon.
Figure 1 is a front elevation of a dynamo machine of the type above named constructed
according to my Improvements.
Figure 2 is a longitudinal section Figure 3 a sectional end elevation and Figure 4
a plan.
Figures 2, 3 and 4 being on an enlarged scale.
Similar letters refer to similar parts throughout the several views.
In carrying out my Invention I cast the chief parts of the machine in one piece,
said parts embodying (1) the main frame or bedplate a. (2) the magnet comprising
the keeper or yoke a underneath the bed and the magnet cores or legs a² terminating
in the pole pieces a³ above the bed, and (3) also standards a' on the bedplate for carrying
the pedestals b which form the bearings for the armature shaft c by this means I lessen
the height of the pedestals and so increase their stability.
To obviate the difficulty of winding the magnet I wind suitable wire on separate slips d
which slips I pass over the pole pieces a³ and on to the cores a³; to enable me to pass
the slips over the pole pieces I do not extend the pole pieces a³ to embrace so large
a portion of the surface of the armature as is usually the case in machines of this
class.
The armature I prefer to construct on the Gramme system or according to any other
suitable form of drum armature. The conducting wire may be wound on the core in
the usual way as shown or in any other convenient way.
For the sake of convenience and cheapness of construction prefer to make up the
armature core as follows:-I key or otherwise secure the bosses of two brass or other
diamagnetic metal spider wheels or rings e e with arms el suitably arranged on the
armature shaft c; these spider wheels or rings e are connected together by bolts fover
which is placed an insulating bush upon which the iron core of the armature rests the
whole being secured in position by tightening up the nuts on the bolts f.
The above described construction permits the free admission of air through the spaces

page_text: between the arms e¹ to the interior of the armature and in furtherance of this I secure
when found desirable fins or vanes on the said arms e¹ to exhaust and draw fresh air
through the interior of the armature so as to prevent the inside coils from heating.
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 dynamo electric machine the magnet cast in one piece with the bedplate
substantially as herein described.
2. In a dynamo electric machine the magnet and also standards for the pedestals
or bearings of the armature shaft cast in one piece with the bedplate substantially as
herein described.
3. The general construction combination and arrangement of parts substantially as
herein set forth.