Improvements in Armatures of Dynamo Electric Machines.
Year: 1890

page_text: Date of Application, 19th Nov., 1890
Complete Specification Left, 19th Aug., 1891-Accepted, 3rd Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in Armatures of Dynamo Electric Machines.
I, JOHN HENRY HOLMES of Portland Road Newcastle-on-Tyne Electrical
Engineer do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in armatures of dynamo electric machines
and it has for its object to prevent the conductors upon the exterior surface of the
core of the armature being displaced by the drag upon them which results when
the conductors carrying current are revolved in the magnet field of the machine.
The invention only relates to armatures having the whole or nearly the whole of
the exterior surface covered by the conducting wires. To prevent the slip or
displacement of the wires I make longitudinal grooves along the surface of the iron
core & I arrange the conductors so that they lie in the said grooves. These
grooves are made quite shallow & close or almost close together so that when the
conductors are placed in the grooves the whole or nearly the whole of the surface
of the core is covered by wires. The iron does not come to the surface between
the conductors as is the case in an armature wound on the Pacinotti method.
When round conductors are used the grooves are made hollow to correspond & in
section they are made less than a semicircle.
In the case of rectangular conductors I prefer to make the grooves of a V shape
similar to ordinary saw teeth, making them to slope in one way or the other
according to the direction of rotation.
To keep the conductors in position I bind the armature in the usual way with
bands of steel wire taking care that these are strong enough & tight enough to
prevent the conductors sliding up the inclined sides of the grooves when the drag
comes upon them.
OL
1000
JOHN H. HOLMES.
COMPLETE SPECIFICATION.
Improvements in Armatures of Dynamo Electric Machines.
I, JOHN HENRY HOLMES of Portland Road, Newcastle on Tyne in the County
of Northumberland Electrical Engineer do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
This invention relates to improvements in armatures of dynamo electric machines
and it has for its object to prevent the conductors upon the exterior surface of the
core of the armature being displaced by the drag, or pull, upon them which results
when the conductors carrying current are moved in the magnetic field of the
machine.
The invention only relates to armatures having the whole or nearly the whole of
the exterior surface covered by the conducting wires. To prevent the slip or
displacement of the wires, I make longitudinal grooves along the surface of the
iron core, and I arrange the conductors so that they lie partly within the said
grooves. These grooves are made quite shallow and close or almost close together,
so that when the conductors are placed in the grooves, the whole or nearly the
whole of the surface of the core is covered by the wires.
The iron does not come to the surface between the conductors as is the case in
an armature wound on the Pacinotti method. When round conductors are used
the grooves are made hollow to correspond, and in section they are made less than

page_text: a semicircle. In the case of rectangular or trapezoidal sectioned conductors, I
prefer to make the grooves of a V shape, similar to ordinary saw teeth making
them to slope in one way or the other according to the direction of rotation.
To keep the conductors in position I bind the armature in the usual way with
bands of steel wire, taking care that these are strong enough and tight enough to
prevent the conductors sliding up the inclined sides of the grooves when the drag
comes upon thein.
In describing this invention more particularly I refer to the accompanying
drawings:
--
Figure 1. represents an armature with core grooved for round or stranded
conductors,
Figure 2 for rectangular conductors, and
Figure 3. for a special conductor of trapezoidal section.
The arrows indicate the direction of rotation of the armatures. In each case
S is the spindle, A the supporting arms, B the binding wires, C the armature core,
D the stranded or laminated conductor and G the grooves. The angular grooves
have a right or left handed slope according to the direction of rotation.
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 :-
Armatures for dynamo electric machines and motors constructed and arranged
substantially as described and as shown in the accompanying drawings for the
purposes set forth.
Dated this 17th day of duo 1901
JOHN HENRY HOLMES.