AN IMPROVED DYNAMO-ELECTRIC MACHINE,
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Thomas Floyd and Thomas
Kirkland at the Office of the Commissioners of Patents on the 11th May
1882.
THOMAS FLOYD, Civil Engineer, of 3, Victoria Mansions, in the City of West-
minster, and THOMAS KIRKLAND, Junior of 32 Palace Road Upper Norwood,
Civil Engineer, "AN IMPROVED DYNAMO-ELECTRIC MACHINE,"
In these machines the Electro-motive force and consequently Current (the
Resistance remaining the same) varies directly as the speed with which the "Lines
of Force," coming or radiating from the Field Magnets, are cut by the wires of the
armature.
We therefore propose to make the Field Magnets themselves revolve, and in a
direction opposite to that of the Armature, so that if both were being driven at a
speed say of 1000 revolutions per minute, the speed with which the lines of force
were being cut would be the same as if the Field Magnets were fixed and the
Armature driven at 2000 revolutions per minute-thus getting the same result
from a machine driven at a moderate speed as one constructed on the present system
driven at a very high speed, or if driven at a maximum speed, obtaining twice the
amount of electricity that could be obtained from one constructed on the ordinary
plan.
The Field Magnets we would construct in sections, coupling each up "in series,"
and so obtain consequent points forming North & South Poles at extremities of a
diameter. By this means a space would be left between each section, so that air
could circulate freely & keep them cool. Revolving rapidly & being furnished with
air spaces as described, they could be wound with finer wire than is ordinarily
used, thus obtaining a more intense field for the same weight of wire employed.
We would also make the poles of the Field-Magnets to almost embrace the
armature the neutral points being joined one to another by Brass Strips, so
forming a complete cylinder which could then be bored out and the armature
being turned would run very close together, so obtaining the maximum effect of
the Field.
These Poles would be bolted to the Field Magnets.
The end Frames would be insulated from and bolted to the Field Magnets, these
would also form the Journals in which to revolve, and on to one end of which the
driving pulley would be keyed, and on the other would be secured wrought iron
studs, on which would revolve taper brass rollers for collecting the electricity as
generated on the commutators; from the Rollers, Wires would pass round the Field
Magnets and back to the solid commutators, the one being insulated from the other,
from which the electricity would be collected by brushes, which would act as
terminals to the "line."
The solid commutators would be supported by studs from the End Frame of
Field Maaneta

page_text: THE REVOLVING ARMATURE.
In order to get rid of the difficulty of winding, and the useless wire which is
coiled round the ends and underneath the inner iron ring as in the Gramme, also
to allow the air to freely circulate both inside & outside, and in order to do any
repairs which may be required to the wire, without taking to pieces more than that
portion in which the damage occurs, and also to reduce the internal resistance, we
propose constructing it in the following manner.
The circumference of the armature is divided into 24 gaps or spaces, (which
number may be increased if desired) between each of which occurs one of the cast
iron radial bars of the Frame. In each of these spaces is placed a bundle of insulated
copper wires, but with their ends joined together & brazed or soldered to the end
brass caps. These caps have each tail pieces, so as to easily form a connection with
the commutator and the next section of wire. Each bundle of wire, with its cap,
then forms a distinct & easily removable section-the caps fitting tightly into the
insulated ends of the armature, which we would make of compressed asbestos,
ebonite or other suitable insulating material. On the sides of each section and
between the iron bars we would place asbestos paper, or other suitable substance,
so as to insure good insulation.
Each section would be connected to one bar of the commutator and from the
same tail piece by one thick wire to the tail piece of the next section at the
opposite end, thus forming a complete ring of wire, similar in principle to that of
Paccinotti.
The cast iron framing (made malleable to get it to take and dispel magnetism
as rapidly as possible) we propose to construct with a boss, keyed on to the shaft
from which radiate bars forming between each the receptacle for the wire, and
being turned on the top and running close to the poles of the Field Magnets, greatly
intensify the inductive effects in the coils. We would separate the ends of the
framing, so as to avoid currents circulating, and, if found necessary, the boss might
be split and insulating material inserted; as well as between the boss and the
shaft.
The insulating ends of the armature we would attach to the cast Framing by
screws.
The Commutator we would make with bars inclined to the shaft on which it is
fixed, so that the collecting Rollers whose centre lines are in the same plane as the
centre line of shaft, always touch two of the bars, so as to avoid sparking due to
make and break of contact.
The axis of each roller we would slightly incline to that of the shaft, (tho' in
the same plane), so that there would be a resolved portion of the centrifugal
force along the shaft tending to keep the rollers in good contact with the
commutator.
We would bind the whole of the wires &c. together by fine wire wrapped round
the outside in say three or more places and well insulated from the Coils.
According to a modification of the above arrangement, we may go farther, and
make the revolving armature to embrace the Field Magnets both inside and outside,
thus cutting almost all the lines of force given out, those on the outside being now
wasted.
In this machine the outside and inside armatures would both revolve in one and
the same direction, while the Field Magnets which would be placed in the middle
between the two, would revolve in the opposite direction.