AN IMPROVEMENT IN MULTIPOLAR ELECTRIC MACHINES to be as follows:
Year: 1884

page_text: I, JOSEPH DEVONPORT FINNEY ANDREWS of Woodside Electric Works, Woodside
Road, Glasgow in the County of Lanark, Electrical Engineer, do hereby declare
the nature of my Invention for "AN IMPROVEMENT IN MULTIPOLAR ELECTRIC
MACHINES to be as follows:-
"
My invention relates to multipolar dynamo-electric or electro-dynamic machines
which have for their armatures coiled rings of the Pacinotti or Gramme kind, and
consists chiefly in so connecting the coils to each other and to the plates of the
commutator that an even number of polar fields, such as 4, 6, 8 &c may be arranged
around the ring to operate effectively on the coils, producing greater power and
uniformity of action than when only two polar fields are employed.
The mode of connection of the armature coils which I adopt will be best
understood by reference to the accompanying diagrams, figs. 1, 2 and 3 shewing
respectively the connections suitable for 4, 6 and 8 polar fields, which are indicated
by the letters N. S. There is a number of coils on the armature ring R, differing
by one from a multiple of half the number of poles, and a corresponding number of
plates on the commutator C; in the diagrams there are 17 coils and 17 commutator
plates. In each case, the two ends of any coil are connected to those of other coils
and to the commutator plates in the following manner. In fig. 1, shewing 4 polar
fields, coil 1 has one of its ends connected to one end of 9 and its other end con-
nected to the opposite end of 10, and these connections are connected respectively
to plates 1 and 10 of the commutator. In like manner, coil 2 has its one end
connected to 10 and its other end to 11, connections being made from these to
plates 2 and 11 of the commutator. And thus all round the ring, each coil has its
ends connected to the two coils which are situated one on each side of a point in
the ring diametrically opposite to it, or to the 8th in order from it each way.
In fig. 2 shewing 6 polar fields, coil 1 has its ends connected to 7 and 12, coil 2
to 8 and 13 and so on, that is to say, each coil is connected to the sixth in order
from it each way.
In fig. 3 shewing 8 polar fields, coil 1 has its ends connected to 5 and 14, coil 2
to 6 and 15, and so on, that is to say each coil is connected to the 4th in order from
it each way.
There might obviously be around the ring an even number of polar fields greater
than 8, and on the ring a number of coils exceeding 17, and the connections of the
coils would be arranged in a manner similar to that described, so as to bring

page_text: together in each case the action of all coils that are approximately in the same
phase. In fig. 2, for instance, when the coils 1 and 7 are entering the S-field,
coil 12 with which these are connected is about to enter it; so the connected coils
4, 10 and 16 are in N-fields-in fig. 1 in like manner, coils 2, 10 and 11 are in
S-fields-in fig. 3 again coil 12 being in an N-field, so also are coils 4, 8 and 16
with which it is connected. For very delicately adjusting the pressure of the
brushes on the commutator, I fix each brush holder on a spindle capable of turning
in a bearing and having projecting from it a stud engaged in a helical alot of a
sleeve which can be moved lengthwise but is prevented from turning. On moving
this sleeve longitudinally by a screw, its helical slot acting on the stud of the 1
brush spindle causes it to turn a little round thus moving the brush which it
carries a little nearer to or farther from the periphery of the commutator.
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.

page_text: COMPLETE SPECIFICATION.
An Improvement in Multipolar Electric Machines.
I, JOSEPH DEVONPORT FINNEY ANDREWS of Woodside Electric Works, Woodside
Road, Glasgow in the County of Lanark, North Britain, Electrical Engineer do
hereby declare the nature of my invention for "AN IMPROVEMENT IN MULTIPOLAR
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 multipolar dynamo-electric or electro-dynamic machines
which have for their armatures coiled rings of the Pacinotti or Gramme kind, and
consists chiefly in 80 connecting the coils to each other and to the plates of the
commutator that an even number of polar fields, such as 4, 6, 8 &c may be arranged
around the rink to operate effectively on the coils, producing greater power and
uniformity of action than when only 2 polar fields are employed.
The mode of connection of the armature coils which I adopt will be best
understood by reference to the accompanying diagrams Figs. 1, 2 and 3 shewing
respectively the connections suitable for 4, 6 and 8 polar fields which are indicated
by the letters N, S. There is a number of coils on the armature ring R differing
by one from a multiple of half the number of poles, and a corresponding number of
plates on the commutator C; in the diagrams there are 17 coils and 17 commutator
plates. In each case, the two ends of any coil are connected to those of other coils
and to the commutator plates in the following manner. In Fig. 1 shewing 4 polar
fields, coil 1 has one of its ends connected to one end of 9 and its other end con-
nected to the opposite end of 10, and these connections are connected respectively
to plates 1 and 10 of the commutator. In like manner coil 2 has its one end
connected to 10 and its other end to 11, connections being made from these to
plates 2 and 11 of the commutator. And thus, all round the ring, each coil has its
ends connected to the two coils which are situated one on each side of a point in
the ring diametrically opposite to it, or to the eighth in order from it each way.
In Fig. 2 shewing 6 polar fields, coil 1 has its ends connected to 7 and 12, coil 2
to 8 and 13 and so on, that is to say each coil is connected to the sixth in order
from it each way.
In Fig. 3 shewing 8 polar fields, coil 1 has its ends connected to 5 and 14, coil 2
to 6 and 15, and so on, that is to say each coil is connected to the fourth in order
from it each way.
There might obviously be around the ring an even number of polar fields greater
than 8, and on the ring a number of coils exceeding 17, and the connections of the
coils would be arranged in a manner similar to that described, so as to bring
together in each case the action of all coils that are approximately in the same
phase. In Fig. 2 for instance, when the coils 1 and 7 are entering the S field,
coil 12 with which these are connected is about to enter it; so the connected coils
4, 10 and 16 are in N fields;-In Fig. 1, in like manner coils 2 and 11 are in
S fields and 10 about to enter-in Fig. 8 again coil 12 being in a N field, so also
are coils 4, 8 and 16 with which it is connected,

page_text: For very delicately adjusting the pressure of the brushes on the commutator,
I fix each brush holder on a spindle capable of turning in a bearing and having
projecting from it a stud engaged in a helical slot of a sleeve which can be moved
lengthwise but is prevented from turning. On moving this sleeve longitudinally
by a screw, its helical slot acting on the stud of the brush spindle causes it to turn
a little round, thus moving the brush which it carries a little nearer to or farther
from the periphery of the commutator.
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
In multipolar electric machines wherein a coiled ring revolves through two,
three or more pairs of polar fields, connecting the coils of the ring to each other
and to the commutator in such manner that all coils that are approximately in the
same phase at the same time are made to act together, substantially as and for the
purpose herein set forth.