Improvements in Dynamo-electric Machines.
Year: 1899

page_text: Date of Application, 30th Dec., 1899-Accepted, 10th Feb,,
1900
COMPLETE SPECIFICATION.
Improvements in Dynamo-electric Machines.
We, THE BRITISHI THOMSON-HOUSTON COMPANY, LIMITED, of 83, Cannon Street,
in the City of London, Electrical Engineers, do hereby declare the nature of our
said invention (which has been communicated to us from abroad by Henry G.
Reist, residing at Schenectady, in the County of Schenectady, State of New York,
United States of America, Electrical Engineer) and in what manner the same is
to be performed, to be particularly described and ascertained in and by the follow-
ing statement:-
This invention relates to that type of dynamo-electric machines, in which ter-
minals for both direct and alternating currents are provided, the improvements
bearing more especially upon the commutator and collector of such machines,
although some features of the improvements are also applicable to direct-current
machines alone.
The principal object of the invention is to economize the horizontal space
occupied by the machine and permit a short shaft to be employed. The invention
finds its largest scope of employment in rotary converters in which direct cur-
rent is converted into alternating current or vice versa, and in the so-called
double current generators."
In carrying out our invention we mount the commutator upon the armature
so as to overhang its hub and under the overhanging commutator we mount the
collector, thus saving horizontal room by permitting one of these devices to nest
within the other. So far as this feature of our invention is concerned, the com-
mutator employed may be of any ordinary or approved style of construction.
The enlargement of the commutator to admit the collector within it permits the
employment of a large number of commutator-segments, and admits the possi-
bility of high potentials being imposed at the direct-current terminals.
A further object of our invention is to provide the commutator whether of
machines of the class above described or of ordinary direct current apparatus,
with certain details of construction the novelty of which will be hereinafter more
fully pointed out. The novel features of our invention will be specifically indi-
cated in the claims.
In the accompanying drawings, Fig. 1 is an end elevation of a part of a
machine embodying our improvements, and Fig. 2 is a sectional elevation of the
commutator and collector end of a machine embodying our improvements..
1 represents a spider, upon which the core-plates of the armature, indicated
at 2, may be mounted in any ordinary approved manner; and 3 represents the
or otherwise a
field magnets. We secure to the spider by a number of lag-bolts
casting forming an annulus to support the commutator, as indicated at 4, pro-
vided with a plurality of arms 5 adapted to shut against the arms of the spider,
and be rigidly connected thereto by bolts, as indicated. The arms 5 suspend the
commutator over the hub 6 of the spider, and in the space thus provided we
mount a collector for alternating currents. So far as our present invention is
concerned, this collector may be of any suitable type of construction. It consists

page_text: of a supporting shell 7, upon which are mounted a plurality of collecting rings 8,
8, 8b, according to the number of phases of the alternating current, the rings
being insulated from the supporting shell by cylindrical septa, as 9, of mica
or other, insulating material. The collecting rings are separated one from another
by annular barriers, as 10, of insulating material, all of the parts being held
against an inner flange of the shell by a clamp-ring 11, drawn firmly into place
by set-screws as indicated. From each collector ring lead a plurality of metallic
terminals 12, with which suitable connection may be made with the armature
winding in the ordinary manner. Upon the annular support 4 for the commu-
tator is applied a band of mica or other insulating material, and the commutator-
bars are set thereon and clamped in place by a plurality of segmental plates 13.
13ª, formed by sawing a complete ring casting into a considerable number of
segments. The outer edges of these plates overhang the commutator bars, and are
notched or grooved to form a seat for a beading as 14, 14% of insulating material.
such as indurated fibre, rising above the plane of the commutator bars and that of
the clamping plates, and thus forming a barrier against leakage of current due to
oil or dirt. This beading forms, when the parts are assembled, a ring, indicated
in dotted lines in Fig. 2, the sections being connected by thin dowels of mica
set in slots or sockets formed in the ends of the segments, as indicated at 15, 15ª,
etc. The connecting plates prevent oil from oozing between the joints in the
segments of the beading. The clamp-plates are drawn firmly up against the
commutator-bars, the beading of course being interposed,-by means of bolts 16
extending through the commutator-support; and the commutator-bars are drawn
down firmly against the support by a plurality of wedges 17, 17ª, lagged or bolted
to the clamp-plates, one such wedge being preferably employed at each joint
between two adjacent clamp-plates. Thus when the commutator bars and clamp-
plates are assembled, the wedges 17, 17ª are screwed home and bring the commu
tator-bars firmly against its support. The co-operating faces of the support and
clamp-plates may be of any suitable conformation to co-operate with the wedges.
As shown, the inner edges of the support are bevelled, and the clamp-plates are
provided with an overhanging right-angled flange against which the wedges bear
when being bolted home.
An organization of the kind herein described is particularly advantageous
when high-potential direct currents are generated or absorbed in the machine,
since the large diameter of the commutator admits of the employment of a large
number of segments with a correspondingly low potential between adjacent seg-
ments. By the form of construction of the commutator-support we derive the
additional advantage of affording room for the collector beneath the commutator
so as to reduce the horizontal space occupied by the armature.
The other parts of the machine illustrated in the drawings may be of any ordi-
nary construction, and require no further explanation. 18 represents the brush-
holding ring as this however forms no part of our invention, and is of well
known construction, no detailed description or illustration is deemed necessary.
Within the term "dynamo-electric machine," as employed herein we include
either generators or motors, as it will be obvious that our invention is applicable
to either, and may be employed whether the machine be designed simply to
generate or absorb a direct or alternating current or both, or to absorb one and
generate the other.
Having now particularly described and ascertained the nature of our said in-
vention (as communicated to us from abroad) and in what manner the same is to
be performed, we declare that what we claim is:-
1-A dynamo-electric machine provided for alternating current and direct-
current provided with a commutator and collector overhanging one another in
a plane transverse to the shaft.
2-A dynamo-electric machine provided with alternating-current and direct-

page_text: current terminals and corresponding armature circuits, and a commutator and
collector between the terminals nesting within one another.
3-A dynamo-electric machine provided with alternating and direct-current
terminals and armature circuits connected therewith, a commutator mounted
upon the armature and overhanging the shaft, and a collector for alternating
currents mounted within said commutator.
4-A rotary converter provided with direct and alternating-current leads, a
commutator and a collector connecting the said leads and superposed one over
the other in the same plane transverse to the shaft.
5-A dynamo-electric machine provided with a collector mounted close to the
shaft, and a commutator overhanging said collector and secured to the armature-
spider by a plurality of arms.
6A commutator for a dynamo-electric machine, provided with a annular sup-
port for the commutator-bars, a plurality of segmental clamp-plates engaging
the commutator bars and overhanging the inner side of the annular support, and
wedges between the inner side of the support and the clamp-plates to bind the
commutator-bars firmly against the support.
7-A commutator for a dynamo-electric machine, comprising an annular sup-
port, an annular range of clamp-plates overlapping the ends of the commutator-
bars, and a beading of insulated material locked in place by the clamp-plates and
rising above the plane of the commutator-bars.
8A commutator for a dynamo-electric machine, comprising an annular sup-
port, a circular range of commutator-bars thereon, a circular range of segmental
clamp-plates overlapping the ends of the bars, and a circular range of insulating
strips locked between the clamp-plates and the commutator bars and rising above
the plane of the commutator bars.
9 A commutator for a dynamo-electric machine, comprising an annular sup-
port, a circular range of commutator-bars thereon, a circular range of clamp-
plates at the ends of the bars, annular insulating barriers between the bars and
the clamp-plates, and means for preventing leakage between the commutator bars
and the clamp-plates at the joints of the barrier-segments.
10 A commutator for a dynamo-electric machine, comprising an annular sup-
port, clamp-plates for the commutator bars and an insulating beading between
the clamp-plates and the bars, formed of a ring of segments connected at the
joints by insulating dowels.
Dated this 28th day of December 1899.
THE BRITISH THOMSON-HOUSTON CO. LTD.,
ALFRED CLEMENTS,
Assistant Secretary.
A. R. MONKS,
Managing Director.