Improvements in Dynamo-electric Machines.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in Dynamo-electric Machines.
STE
I ALBERT LYMAN PARCELLE of 157 Washington Street Boston in the State
of Massachusetts United States of America Electrical Engineer 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:—
My invention relates to that class of multi-polar dynamos having ring-armatures
rotating around radial field-poles; and is designed inore especially as an electrical
motor.
Its objects are to provide a simple, economical, and commercially efficient
slow speed multi-polar motor, the ring armature of which shall at all times have a
maximum amount of active wire, and each field-pole shall act simultaneously on a
number of armature-coils, all tending to cause rotation in the same direction, and
no dead-points; to employ a large armature giving favorable leverage, and
relatively low electrical and magnetic resistance; so to organize the machine
that the centrifugal force caused by the rotation of the armature tends to withdraw
its coils from the faces of the field-imagnets, and to provide for the proper mounting,
casing and ventilating of the armature.
These ends attain by mounting a series of multiple radial field-magnets in
the same vertical plane in suitable supports, and surrounding them by a concentric
continuous Gramme-ring armature supported by, and enclosed in a suitable frame
or casing mounted on a rotating shaft.
The subject-matter claimed consists of certain novel constructions, combinations,
and organizations of instrumentalities hereinafter claimed.
The accompanying drawings represent only so much of my improved machine as
is necessary to illustrate the subject-matter claimed; unless otherwise indicated, the
construction is well known.
Figure 1 is a diagramatic end or face view illustrating the organization of the
field-magnets, armature coils, and circuit-connections.
Figure 2 a vertical, central, longitudinal section through the machine; and
Figure 3, a view similar to Figure 1, of a modified organization.
The cores of the field-magnet- A, are preferably mounted upon, and in magnetic
connection with, or are solid with an iron hub or yoke B, secured to a standard
or frame B'. These cores are so wound as to produce alternate north and south
poles, and preferably wound successively so that each pair of adjoining cores con-
stitutes a U-magnet, the circuit of which is completed by the yoke B. The
drawings show eight of such cores, constituting four U-shaped radial magnets all
lying in the same vertical plane, and all permanently active or energized when the
machine is in operation.
The armature is a Gramme ring consisting of a continuous iron core, encircled
by continuous and contiguous coils C, wound in groups: forty-eight of such coils
The arinature is
are shown as arranged in eight group of six coils each.
preferably made thin and flat, and of a width equal to that of the field-cores,
which are oval shaped or flattened parallel with their shaft.
As the centrifugal force generated by the revolution of the armature tends to
drive its inner convolutions away from the field-poles, they may be run very close
together.
The armature is shown as firmly secured on the inner surface of an annular rim
or casing, by means of teeth c. thereon, interlocking with the coils by projecting
inwardly in the space between the coil. This case is preferably of non-magnetic
metal

page_text: errocking holds the coils hrmly, and prevents their lateral
displacement, without the necessity of employing bolts or fastenings, which would
interrupt the continuity of the coils and tend to produce deleterious magnetic
effects. The teeth are in the form of thin transverse plates or ribs, only wide
enough properly to separate the groups of coils. The rim C, in which the armature
is mounted is carried by a frame, plate, or spider C, radiating from a hub C³,
fast on a revolving shaft Fall these parts preferably being of metal. The opposite
end of the casing is closed by a metal disc, plate, or spider (", turning on a
bearing C, on the frame or standard B.
A commutator D, on this shaft may be clamped against the hub C³, or frame C³,
by a screw-nut D' or in other ways.
Brushes E, F, are shown in Figure 2. as supported by a bracket E' of insulating
material mounted on the frame or standard B, and capable of turning thereon to
swing the brushes in either direction.
The commutator-strips are connected with the terminals of their respective
armature-coils by wires .r. united at one end with its respective strip, and branches
at the other so as to be connected with the adjacent terminals of the appropriate
armature-coils.
If a solid plate or frame C is used, these wires are brought out to the com-
mutator through perforations .r'. Metal rings d, insulated from each other in the
commutator-hub, connect the commutator-strips in groups. Figure 1. represents
this arrangement diagramatically, showing four groups of twelve strips cach, corre-
spondingly numbered, with the corresponding numbers of each group connected.
The brushes E, F, are shown about forty-five degrees apart.
The current may be assumed to enter by the brush E, resting on n strip
numbered 1, and to depart by brush F, on a strip numbered 7.
The result of the above described organization is to keep all the coils con-
tinuously active, those in front of each field-pole tending at all times to produce
rotation in the same direction. For instance, assuming the polarities of the field
magnets to be as marked in Figure 1. and the currents traversing the strips as above
described, there will be eight groups of six coils each, one group in front of each
field-pole, all tending to rotate the armature in the same direction, which relative
condition is maintained so long as the armature revolves. There are, therefore,
practically no dead points, and practically all the wire of the armature is active at
all times.
If the brushes be shifted forty five degrees, the motor will be reversed, i.e., if
they be so shifted that brush E. is upon a 7 strip, and brush F. upon ก strip, the
direction of rotation of the motor will be reversed. Placing the brushes upon
the strips 10, and 4, respectively, produces a condition of equilibrium opposite cach
field-pole, and stops the rotation.
I may of course employ a separate pair of brushes for each U-magnet by
omitting the connection of the commutator strips through the rings. Were six
field-poles used, I might employ three pairs of brushes, or where eight poles are
used, as herein shown, there may be four pairs of brushes. In that event, each
U-magnet would practically be the field of a separate motor; all, however, com-
bined in one machine which could be regulated according to the requirements by
throwing brushes into and out of action.
Figure 3 shows this organization, each pair of brushes being indicated
as being capable of being thrown into or out of action, independently of all
the others, by being mounted on rock-shafts, linked together in pairs, each con-
trolled by its own lever. Of course when a pair of brushes is thrown out of
action, the armature coils in advance of the corresponding field-poles would
practically be idle; they will, however, receive some current, but being shunted
by the active coils supplied by the adjacent pairs of brushes, the amount of current
passing through them will be small. The throwing of the brushes into and out of
nction afford, therefore, convenient means for adapting the capacity of the motor
to the work to be done.

page_text: It will be seen from the foregoing description that one of the principal
characteristics of my improved machine is the combination of radial, multiple
field-poles, lying in the same plane with continuous groups of armature-coils,
constituting a Gramme-ring; cach group of coils being active in front of its
respective field pole, and all the groups co-operating to produce rotation in the
same direction; that is to say; the coils forming the groups continually and
successively change relatively to each pole-piece, as they advance past it, the place
of each coil dropped or disconnected from a group in rear of the pole being
supplied by a new one advancing at the front.
The advantages incident to my improved organization hereinbefore have been
recited in part.
Iain besides enabled to use a ring-armature of large diameter,
with a consequent increase in the number of field-poles, and to run the motor at a
comparatively slow speed. The perforations in the discs, plates, or spiders C³, C',
afford ample ventilation, and permit access to the armature and field-coils.
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. The combination, substantially as set forth, of a series of multiple field-magnet
poles of alternate polarity, arranged radially in the same plane; a Gramme-
ring armature consisting of continuous connected groups of multiple coils arranged
outside of the field-poles and in the same plane; a frame or casing carrying the
armature; a commutator; its brushes; and electrical connections between the
commutator strips and their appropriate armature coils; whereby a number of
armature coils are continuously active in front of each field-pole and adjoining
groups of such coils in front of adjoining field poles of opposite polarity co-operate
in producing continuous rotation of the armature.
2. The combination, substantially as set forth, of a fixed hub or frame carrying
the field-poles, the surrounding ring armature having multiple coils, and the
casing surrounding and carrying the armature, and interlocking and rotating
therewith.
3. The combination, substantially as hereinbefore set forth, of a rotating casing;
its flat annular flange or rim, transverse ribs or teeth on the inner sides of the
rim; and a Gramine-ring armature the continuous coils of which inter-lock with
the teeth to hold the coils securely in place.
4. The hereinbefore described multipolar dynamo machine, consisting of the
combination, substantially as hereinbefore set forth of a supporting standard; a
yoke fixed thereon; radial field poles connected with the yoke; a main shaft ;
enclosing discs, plates or arms mounted thereon and rotating therewith, an annular
flange or rim of the casing surrounding the field poles; a Gramme-ring armature
consisting of continuous connected groups of coils secured inside said rim, in close
proximity to the field poles, commutators, their brushes, and electrical connections
between the brushes and each group of their appropriate armature coils.
Dated the 21st day of April 1891.
PHILIP M. JUSTICE,
55, Chancery Lane, London, Associate Agent.