Improvements in Alternating-current Dynamos.
Year: 1895

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 11 of the Patents, &c., Act, 1883), as required by
the decision of the Chief Examiner of the 18th day of July 1896.
Date of Application, 8th July, 1895
Complete Specification Left, 4th Oct., 1895-Accepted, 28th Dec., 1895
Improvements in Alternating-current Dynamos.
A communication from abroad by the MASCHINENFABRIK OERLIKON, of
Oerlikon, Switzerland.
I, WILLIAM LLOYD WISE, of 46 Lincoln's Inn Fields, in the County of
London, Consulting Engineer and Chartered Patent Agent, do hereby declare the
nature of this invention to be as follows:-
The alternating-current dynamo forming the subject-matter of this invention
belongs to the class of alternators in which the electro-motive force of the armature
is produced by the periodical change in number, but not in direction, of the
magnetic lines of force that cut the coils of the armature and in which the rotary
An alternator
portion of the machine is not provided with any current-conductor.
of this class essentially comprises two like co-axial sheet-iron rings of rectangular
cross-section, which at their inner edges carry the coils of the armature in
uniformly distributed number of grooves or holes. These two sheet-iron rings are
carried by a cast iron or cast steel cylindrical casing consisting of two or more
parts, the outer edges of the rings being in contact at both sides with the interior
of the cast casing. The magnetising coil is embedded in the annular groove
between the two rings. The two wound armature-rings, the cast casing, and the
magnetising coil compose the stationary portion of the alternator.
a
The rotary portion of such alternators has hitherto consisted of an iron-cylinder
carrying at each end a ring of projections or teeth, which are opposite to the
armature-rings and the number of which is equal to the number of pairs of poles
of the alternator. The magnet of toothed-wheel shape thus formed serves as a
magnetic yoke or connection between the two armature-rings.
Now according to this invention the number of the grooves or holes in the
armature-rings, and consequently the number of the inserted coils or bobbins, is,
in the case of monophase-current machines made equal to the number of the pairs
of poles, and in the case of poly-phase-current machines is made equal to the
number of the pairs of poles multiplied by the whole of, or half, the number of
the phases of the system. In this way, the number of the separate armature-
bobbins is made as small as possible and with adequate groove-opening, any
individual bobbin can be wound and insulated outside the machine. Such an
arrangement of the armature-bobbins, which form an equal number of corresponding
pole-teeth, necessitates, however, the lamination of the magnet-projections opposite
to these grooves in order to prevent a loss of energy by the formation of
"Foucault currents" in the magnet. For this purpose there have hitherto been

page_text: attached to the two sides of the magnet, two toothed sheet-iron rings connected
together laterally by an iron-cylinder. According to this invention, however, the
magnet is made up of a number of separate two-legged cast steel bow-shaped pieces,
which are magnetically independent of one another and the number of which is
equal to the number of the pairs of poles. On each leg of each bow-shaped piece
and at the part thereof opposite to the corresponding armature-ring, there are
placed sheet-iron pole-shoes, the arrangement being such that the magnetic lines
of force pass from the pole-shoes, in the direction of the plate-surfaces, into the
massive iron bow-shaped pieces. The several bow-shaped pieces form a number
of yokes between the armature-rings; on mechanical grounds they may be rigidly
connected together, but in star-like construction they are carried by the spokes of
a wheel. This arrangement secures both a considerable economy of material and
an important ventilation and diminution of the magnetic dissipation; whilst the
pole-shoes are comparatively small and do not affect the total magnetic resistance.
Fig. 1 of the accompanying drawings shows by way of example, half in
longitudinal section and half in elevation, a three-phase current alternator
according to this invention, and
Figure 2 being an end elevation of the same with the cast casing or hollow
cylinder removed.
In these figures E represents the cast casing, P the sheet-iron armature-rings
with grooves n wherein lie the armature-bobbins a, m the magnetising-coil, K the
several bow-shaped pieces of the magnet, and Z the sheet-iron pole-shoes.
Dated this 8th day of July 1895.
W. LLOYD WISE,
46 Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.
A communication from abroad by the MASCHINEN-FABRIK OERLIKON, Switzerland.
1, WILLIAM LLOYD WISE, of 46, Lincoln's Inn Fields, in the County of
London, Consulting Engineer and Chartered Patent Agent, do hereby declare the
nature of this invention and in what manner the same is to he performed to be
particularly described and ascertained in and by the following statement :-
The alternating-current dynamo forming the subject-matter of this invention
belongs to the class of alternators in which the electro-motive force of the armature
is produced by the periodical change in number, but not in direction, of the magnetic
lines of force that cut the coils of the armature, and in which the rotary portion
of the machine is not provided with any current conductor. An alternator of this
class essentially comprises two like co-axial sheet-iron rings of rectangular cross-
section, which, at their inner edges, carry the coils of the armature in a uniformly
distributed number of grooves or holes. These two sheet-iron rings are carried by
a cast iron or cast steel cylindrical casing consisting of two or more parts, the
outer edges of the rings at both sides being in contact with the interior of the cast
casing. The magnetising coil is embedded in the aunular groove between the two
rings. The two wound armature-rings, the cast casing, and the magnetising coil
compose the stationary portion of the alternator.
The rotary portion of such an alternator has hitherto consisted of an iron-
cylinder carrying at each end a ring of projections or teeth, which are opposite to
the armature-rings, and the number of which is equal to the number of pairs of
poles of the alternator. The magnet of toothed-wheel shape thus formed serves
as a magnetic yoke or connection between the two armature-rings.

page_text: "
Now according to this invention, the number of the grooves or holes in each
armature-ring, is, in the case of monophase-current machines, made equal to double
the number of the pairs of poles, and, in the case of polyphase-current machines,
is made equal to double the number of the pairs of poles multiplied by the whole
of, or half the number of the phases of the system. In this way, the number of
the separate armature-bobbins is made as small as possible, and with adequate
groove-opening, any individual bobbin can be wound and insulated before being
fixed in the machine. Such an arrangement of the armature-bobbins, which form
an equal number of corresponding pole-teeth, necessitates, however, the lamination
of the magnet-projections opposite to these grooves in order to prevent a loss of
energy by the formation of "Foucault currents
in the magnet. For this purpose
there have hitherto been attached to the two sides of the magnet two toothed sheet-
iron rings connected together laterally by an iron cylinder. According to this
invention, however, the magnet is made up of a number of separate two-legged
cast-steel or iron box-shaped pieces, which are magnetically independent of one
another and the number of which is equal to the number of the pairs of poles.
On each leg of each bow-shaped piece and at the part thereof opposite to the
corresponding armature-ring, there are placed sheet-iron pole-shoes, the arrangement
being such that the magnetic lines of force pass from the pole-shoes, in the direction
of the plate-surfaces, into the massive cast steel or iron bow-shaped pieces. The
several bow-shaped pieces form a number of yokes between the armature-rings;
on mechanical grounds they may be rigidly connected together, but in star-like
constructions they are carried by the spokes of a wheel. This arrangement secures
both a considerable economy of material and an important ventilation by the
rotation of the magnet and diminution of the magnetic leakage; whilst the pole-
shoes are comparatively small and do not affect the total magnetic resistance.
Fig. 1 of the drawings filed with my Provisional Specification shows, by way of
example, half in longitudinal section and half in elevation, a three-phase current
alternator according to this invention having four pairs of poles, and
Fig. 2 is an end elevation of the same with the cast casing or hollow cylinder
removed.
In these figures, E represents the cast casing; P the sheet-iron armature-rings
with grooves or holes n through which the armature-bobbins a extend; m the
magnetising-coil; K the several bow-shaped pieces of the magnet; and Z the
sheet-iron pole-shoes.
In this example, the number of grooves or holes n in each armature ring P is
made equal to twice the number of pairs of magnet poles formed by the pieces K,
multiplied by half the number of phases or 2 x 4 × 3 =
:
2
12.
The accompanying drawing, Fig. 24, is a similar view to Fig. 2. showing a three-
phase alternator in which the number of holes n in each armature-ring P is equal
to double the number of the pairs of magnet poles multiplied by the number of
phases or 2 x 4 × 3 = 24. The armature windings a consist of twelve coils
arranged on the system of drum winding.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I wish it to be understood
that I am aware of the Specification of Letters Patent No. 8262 of A.D. 1887
granted to William Morris Mordey and I do not claim anything described and
claimed therein, but I declare that what I claim is :-
An alternating current dynamo of the type herein referred to, wherein the
number and arrangement of the grooves or holes in each armature-ring is such as
to form polar teeth or projections equal to double the number of the pairs of poles
multiplied by the simple or half number of the phases of the system, and there is
employed in combination with such armature rings, a rotary magnet, which,
without carrying any current conductor, consists of magnetic cast-steel or iron

page_text: bow-shaped pieces, which are magnetically independent of one another, are equal
in number to that of the pairs of poles, and carry on each leg a sheet-iron pole-shoe,
substantially as described.
Dated this 4th day of October 1895.
W. LLOYD WISE,
46 Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.