IMPROVEMENTS IN DYNAMO OR MAGNETO ELECTRIC MACHINES, OR ELECTRIC ENGINES
Year: 1882

page_text: LETTERS PATENT to Thomas John Handford of No 42, Southampton
Buildings in the County of Middlesex, Patent Agent, for an Invention of
"IMPROVEMENTS IN DYNAMO OR MAGNETO ELECTRIC MACHINES, OR ELECTRIC
ENGINES."A communication from abroad by Thomas Alva Edison of Menlo
Park in the State of New Jersey United States of America.
PROVISIONAL SPECIFICATION left by the said Thomas John Handford
at the Office of the Commissioners of Patents on the 9th March 1882.
"
THOMAS JOHN HANDFORD of No 42 Southampton Buildings in the County of
Middlesex Patent Agent. "IMPROVEMENTS IN DYNAMO OR MAGNETO ELECTRIC
MACHINES, OR ELECTRIC ENGINES' A communication from abroad by Thomas
Alva Edison of Menlo Park in the State of New Jersey United States of
America
The object of this invention is such an improvement upon electrical generators
and engines of the Pacinotti type, that the inactive portions of the bobbin will
have a greater cross sectional area, and a lower resistance per unit of length than
the active portions so that the internal resistance of the machine will be reduced to
the minimum
The object is accomplished by forming the bobbin coils, of bars, which extend on
the outside of the ring or annular core parallel or nearly parallel with the axis of
rotation, and of wide plates on the inside of the ring the bars and plates being
connected to produce a continuous bobbin by radial end bars
The bars or coils, preferably the alternate ones, are connected with commutator
bara
The plates which are the main inactive portion of the bobbin, have a very low
resistance lower than that of the active bars
The end or radial bars may also have a greater cross sectional area than the active
bars, or they may be of the same size:
To form the continuous winding, the wide plates within the core may be placed
slightly oblique; or the active bars may be placed slightly oblique and the plates
arranged parallel with the axis of rotation; or the radial end bars can be given the
inclination necessary for this purpose, and both the active bars and interior plates
be placed parallel with the axis.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas John Handford in the Great Seal Patent Office on the
5th September 1882.
"
THOMAS JOHN HANDFORD of No 42 Southampton Buildings in the County of
Middlesex Patent Agent "IMPROVEMENTS IN DYNAMO OR MAGNETO ELECTRIC
MACHINES OR ELECTRIC ENGINES a communication from abroad by Thomas
Alva Edison of Menlo Park in the State of New Jersey United States of
America
The object of the said Invention is such an improvement upon electrical
generators and engines of the Pacinotti type that the inactive portions of the
bobbin will have a greater cross sectional area and a lower resistance per unit of
length than the active portions so that the internal resistance of the machine will
be reduced to the minimum
This object is accomplished by forming the bobbin coils of bars which extend on
the outside of the ring or annular core parallel or nearly parallel with the axis of
rotation, and of wide plates on the inside of the ring the bars and plates being
connected to produce a continuous bobbin by radial end bars
The bars or coils preferably the alternate ones are connected with commutator
bars. The plates which are the main inactive portion of the bobbin have a very
low resistance lower than that of the active The end or radial bars may also
have a greater cross sectional area than the active bars or they may be of the same
size.
In order to form the continuous winding, the wide plates within the core may
be placed slightly oblique; or the active bars may be placed slightly oblique and
the plates arranged parallel with the axis of rotation; or the radial end bars may
have the inclination necessary for this purpose, and both the active bars and interior
plates be placed parallel with the axis
And in order that the said invention may be perfectly understood I shall now
'proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the accompanying sheet of drawings the same letters of
reference indicating corresponding parts in all the Figures
Figure 1 of the accompanying drawings is a perspective view of a portion of the
armature of a machine constructed according to the said invention the annular core
being shewn in dotted lines
Figure 2 is a half end elevation of the armature with the commutator cylinder
and its connections removed and a half cross section of the armature
Fig 3 is a plan of the armature with some of the exterior or active bars removed,
and the annular core shewn partly broken away and in section.
A is the ring or annular core of the armature on the outside of which are the
exterior or active bars B parallel or nearly parallel with the axis of rotation whilst
on the inside of the said ring or core are wide interior plates C having greater cross
sectional area and lower resistance than the active bars and by preference made
thicker at their outer than at their inner edges as shewn, the exterior or active
bars B and the interior plates C being respectively separated from each other and
from the core A by insulating material shewn in black in Fig 2. The exterior or
active bars B and the plates C are connected together by radial end bars D D¹
which may be attached to the former by screws. The plates C which may
alternately rest upon and be set into grooves in the wooden hub A' are arranged
slightly oblique to the axis of rotation in order to form with the active bars B and
the radial end bars D D' a continuous bobbin; the rear end of each plate C being

page_text: attached to one of the radial end bars D' whilst the front end of such plate is
attached to the radial end bar D next to the one opposite to the bar D¹ to which
the rear end of the plate C is attached. The radial end bars D are connected
with bars E forming themselves or connected with the bars of the commutator
cylinder E¹
In lieu of placing the plates C obliquely, the bars B or D. D' may be so arranged
for the same purpose. In place moreover of forming the active bars B separate
from the radial end bars D D¹ and connecting them thereto each active bar B may
be made in one piece with the radial bars D D' at its end, and the commutator
bars E may be formed by bending the ends of the proper bars D outwardly whether
such bars D are made integral with bars B or separate therefrom
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the invention secured to me by the hereinbefore in part
recited Letters Patent is :-
In a Dynamo or Magneto electric machine or electric engine of the type
hereinbefore referred to, the combination with the annular core of the bobbin, of
the active bars, the end connecting bars, and the interior plates having greater
cross sectional area and lower resistance than the active bars, substantially as
herein before described
In witness whereof I the said Thomas John Handford have to this my
Specification set my hand and seal this fifth day of September in the year
of our Lord One thousand eight hundred and eighty two.