IMPROVEMENTS IN DYNAMO- ELECTRIC MACHINES AND ELECTRO-MOTORS
Year: 1883

page_text: LETTERS PATENT to Sir Charles Tilston Bright of 20 Bolton Gardens in the
County of Middlesex-Knight for an Invention of IMPROVEMENTS IN DYNAMO-
ELECTRIC MACHINES AND ELECTRO-MOTORS
PROVISIONAL SPECIFICATION left by the said Sir Charles Tilston Bright
at the Office of the Commissioners of Patents on the 17th November 1883.
Sir CHARLES TILSTON BRIGHT of 20 Bolton Gardens in the County of Middlesex,
Knight IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES AND ELECTRO-MOTORS
My invention consists of improvements in dynamo-electric machines and electro-
motors which have for their object the simplification and increased efficiency of the
apparatus and the reduction of the cost of maintenance and repairs.
In the first part of my improvements I construct alternating current dynamo-
electric machines in which both the armatures (or coils of insulated wire
representing them) and the coils of insulated wire of the field magnets are fixed;
the armatures being excited by movable pole-pieces, the polarity of which is
induced by part of the said pole-pieces being surrounded with, (or in close
contiguity to) the poles of fixed electro-magnets, or by coils of insulated wire, or
by a combination of both.
In my patent N° 2280 of the present year I have described a system of movable
pole-pieces applicable to machines generating a continuous current; This part of
my present invention relates to the further application of the said system to
machines producing alternating currents, in which the moving part is confined to
the metallic shaft and its extensions, and in which the employment of collectors
or commutators is unnecessary, thus avoiding the repairs occurring from the
damage of coils of wire moving at a high speed, and the inequalities of the current
arising from imperfect contact, and the wear between the rubbing surfaces of
collectors or commutators.
The pele pieces, though in near proximity in a part of their surfaces to the poles
of the field magnets, or to coils of insulated wire, do not actually come in contact
with them, and are supported by non-magnetic bearings.

page_text: In carrying out this part of my invention I divide an iron or steel shaft into two
parts in its centre by a piece of brass or other suitable non-magnetic metal, and I
expand the magnetic parts of the shaft at each of their central ends into iron or
steel discs, from the outer edge of which spaces are cut, dividing the discs for a
suitable depth into radial arms which thus form poles, North on one side of the
non-magnetic division, and South on the other.
A fixed ring or other suitable bearing with its centre coinciding with that of the
shaft carries a series of coils of insulated wire either with or without soft iron
cores
My improved system is readily adaptable to any form of coils for such purposes.
Permanent magnets of steel may be employed to polarise the movable pole-pieces
in place of electromagnets or coils of insulated wire, and a combination of steel
magnets and soft iron surrounded by insulated wire will be found suitable under
certain conditions.
Another part of my invention consists in using a shaft of iron or steel passing
through a coil of insulated wire without any non-magnetic division, the indented
discs as previously described being placed at the outer ends of the shaft and
exciting two sets of fixed armature coils, or coils consisting only of insulated wire
without any iron cores.
Another part of my improvements has relation to my system of dispensing with
the rotation of any coils of insulated wire in continuous current machines described
in my patent Number 2280 of the present year
I apply this system to elongated coils of a cylindrical form, usually designated
as the Siemens type, by using a shaft divided in its centre by a non magnetic
division and extending the pole-pieces as therein described, but not in the radiating
direction rectangular to the axis, the form of continuation of the shaft being in the
shape of two segments of a cylinder parallel with the axis of the shaft

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Sir Charles Tilston Bright in the Patent Office on the 17th May
1884.
Sir CHARLES TILSTON BRIGHT of 20 Bolton Gardens in the County of Middlesex,
Knight IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES AND ELECTRO-MOTORS
My invention consists of improvements in dynamo electric machines and electro
motors which have for their object the simplification and increased efficiency of the
apparatus and the reduction of the cost of maintenance and repairs.
In the first part of my improvements I construct alternating current dynamo
electric machines in which both the armatures (or coils of insulated wire
representing them) and the coils of insulated wire of the field magnets are fixed,
the armatures being excited by movable pole-pieces, the polarity of which is
induced by part of the said pole-pieces being surrounded with, (and in close
contiguity to) the poles of fixed electro-magnets, or by coils of insulated wire, or
by a combination of both.
In my patent No 2280 of the year 1883 I have described a system of movable
pole-pieces applicable to machines generating a continuous current; this part of
iny present invention relates to the further application of the said system to
machines producing alternating currents, in which the moving part is confined to
the metallic shaft and its extensions, and in which the employment of collectors
or commutators is unnecessary, thus avoiding the repairs occurring from the damage
of coils of wire moving at a high speed, and the inequalities of the current arising
from imperfect contact, and the wear between the rubbing surfaces of collectors or
commutators.
The pole pieces, though in near proximity in a part of their surfaces to the poles
of the field magnets, or to coils of insulated wire, do not actually come in contact
with them, and are supported by non-magnetic bearings
In carrying out this part of my invention I divide an iron or steel shaft into two
parts in its centre by a piece of brass or other suitable non-magnetic metal, and I
expand the magnetic parts of the shaft at each of their central ends into iron or
steel discs, from the outer edge of which spaces are cut, dividing the discs for a
suitable depth into radial arms which thus form poles, North on one side of the
non-magnetic division, and South on the other.
A fixed ring or other suitable bearing with its centre coinciding with that of
the shaft carries a series of coils of insulated wire either with or without soft iron
cores.
My improved system is readily adaptable to any form of coils for such purposes.
Permanent magnets of steel may be employed to polarise the movable pole-pieces
in place of electro-magnets or coils of insulated wire, and a combination of steel
magnets and soft iron surrounded by insulated wire will be found suitable under
certain conditions
:
At Fig 1 is shown a front elevation, partly in section, of a machine constructed
according to my invention, in which a. a. a. represent the iron parts of an electro-
magnet b. b. b. b being the space occupied by the wire. The poles of the electro-
magnet are shewn in section surrounding the induced shaft or pole-pieces N. S in
close proximity to but not in contact with the poles. An outer ring c. c carries
the fixed armature coils hereafter described d. d are castings of non-magnetic metal
supporting and separating the poles from the bed-plate.
Fig: 2 represents a side elevation of a similar machine to which the same
lettering applies.
-

page_text: Fig 3 shews the construction of the induced pole pieces N. S of the previous
figures which are divided in the centre by a disc of non-magnetic metal e at n. 8
are shewn two of the teeth which form the extremities of N and S.
In Fig 4 c. c is the outer ring of non-magnetic metal shewn under the same
letters as in Figs: 1 & 2 f is one of the series of coils composing the fixed
armature ring
1.
The electro magnets a. a. in the figures 1 and 2 may be excited by a separate
continuous current machine or by a voltaic battery or other electrical generator.
The stationary armature coils are connected to fixed terminals so that no rubbing.
or rolling surfaces or collectors, such as are- - usually employed in alternating
machines, are requisite.
The induced shaft or pole pieces may be substituted for the pole pieces described
in my said patent N° 2280 thus the machine may be adapted to give either
alternating or continuous currents.
The shaft may also be surrounded by coils of wire as shown at Figs 1 and 2 of 1
the said patent No 2280 and referred to in the specification of this patent.
Having thus described the nature of my invention I the said Sir Charles Tilston
Bright have hereto set my hand and seal this sixteenth day of May in the year of
our Lord one thousand eight hundred and eighty four.
CHARLES T BRIGHT (1.8)