Improvements in Electro-motors.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Electro-motors.
We, FREDERIK VILHELM ANDERSEN of 14 Westdown Road Catford Bridge in the
County of Kent, Electrician, and JOHN OWEN GIRDLESTONE of 6 Grove Road
Highgate Road in the County of Middlesex, 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 :-
This Invention relates to electro-motors and it has for its objects to secure simplicity
of construction, to reduce the magnetic resistance of the air space round the armature
to a minimum, to arrange and dispose the iron in the field magnets in the most
effective and economical manner and to reduce the cost of construction and weight of
the machine.
We will describe our Improvements with reference to the accompanying drawings,
in which Fig. 1 is a plan, Fig. 2 an end view, Fig. 3 a side elevation, Fig. 4 a longitudinal
section through the armature, Fig. 5 a transverse section of the armature grooves, and
Figs. 6 and 7 details of a motor constructed and arranged according to our Invention.
The Armature. Upon the armature spindle A there is mounted against a fast collar, a
disc B and a wooden frame or sleeve C. Over the sleeve are placed a series of thin
sheet iron washers 1) between each of which is placed a corresponding thin sheet of
shellacked paper or similar insulator. The core of the armature is completed by a
second disc E, beyond which, the armature spindle is screwed and provided with the
lock nuts F by means of which the sheet iron washers may be compressed between
the discs and be firmly beld in position. Each of the discs and of the sheet iron
washers has formed in its periphery a suitable number of grooves or slots narrowing
towards the bottom; there are thus formed a series of equidistant longitudinal
channels or grooves G in the periphery of the core, to contain the coils of wire with
which the armature is wound. The compression of the core should be effected whilst
the shellac varnish with which the insulating paper washers have been insulated is
still wet, and after the core has been thoroughly dried it should be turned truo on
the outside. In each of the channels G there is inserted a well shellacked lining of
waterproof cardboard or thick paper or some similar and suitable insulator, and at
each end there is placed over the discs B E a disc of similar insulator, whilst the nuts F
and those parts of the spindle A with which the wires might come into contact are
served with three or four plies of well shellacked cloth or are otherwise suitably
insulated. The edges of the grooves where the wires enter and leave should be rounded
to prevent risk of cutting through the insulation.
The winding is effected on the well known drum or Siemens system and should be
well insulated and secured as in ordinary machines of the same class.
The cominutator consists of twice as many segments as there are channels for the
winding on the periphery of the core and it is built up independently of the spindle
on a gun-metal sleeve. Each section of the commutator has a lug H cast upon it
and the outer end of each of these lugs is sawn or cut to a forked shape as shewn in
Fig. 5. At each end of each commutator section a V shaped recess is formed as
represented in Fig. 4. The gun-metal sleeve I has formed upon its inner end a
flange with a V shaped projection and upon its outer end there is fixed a washer also
having a V shaped projection; the outer end of the sleeve is screwed and fitted with
a nut. The sections of the commutator are insulated from the sleeve and washer
by a sleeve and washers of vulcanised fibre or other suitable insulating material and
from each other by strips of mica. The V shaped projections of the sleeve and washer
engage with the corresponding recesses in the commutator sections and hold them
firmly in position. The commutator is held laterally on the spindle between the fast
collar J and the lock nuts K fitted upon a screwed part of the spindle and is prevented
from rotating by a pin fitted into the collar or spindle. The ends of the wires from

page_text: the armature coils are brought into the forks formed in the lugs H, where they
are soldered, the forks are afterwards closed upon the wires to hold them more firmly.
The Field Magnets. The iron of the field magnets consists of two forgings L M.
One of these forgings, and preferably the bottom one, has the two core limbs N N
formed upon it. The top pole piece M is fitted upon the free ends of the core limbs
and is secured thereto by means of bolts as indicated in the drawing. The field
magnet coils are wound on sheet iron bobbins provided with a brass flange at each
end. These bobbins are to be insulated from the winding by means of vulcanised
fibres, shellacked paper or cloth, or other suitable insulating material. The inside end
of each coil is brought out through an insulating collet in the top brass flange and
connected to terminals; the outside ends are well tied off and brought up alongside
the coils to other terminals as represented in the drawing Fig. 3.
Brush Gear. The brushes are constructed in the ordinary manner and are mounted
upon brush holders carried on two spindles 0 0 which are fixed on insulating collets
in a movable ring P provided with a handle and a locking screw.
Terminals. Seven terminals are fixed upon a suitable base placed upon the top of
the machine. The four ends of the two magnet coils are connected to the four
corner terminals QQ. The brushes are respectively connected to the terminals R. T.
The line wires are connected to the terminals S and T. For ordinary work the
terminals QRQ are connected together and the terminals QS Q are also similarly
connected.
Framing. The bed or framing of the machine preferably consists of two angle
iron rails secured to the pole piece M by studs and nuts Ū U, and provided with
the feet W W. The standards or brackets V for carrying the bearings are bolted
directly to the rails.
Gearing. We prefer to transmit the motion of the armature to the countershaft Y
or to a second motion shaft by means of step spur gearing. As represented in the
drawings this gearing consists of the spur pinions 1, 2,13, mounted on the armature
spindle and the corresponding spur wheels, 1, 2, 3, gearing therewith and mounted
upon the second motion shaft. Each of the pinions and wheels have the same
pitch, and the pinions (and consequently the wheels also) have like numbers of teeth.
The pinions and wheels are mounted and keyed on their respective shafts so that
the teeth of 2 are one-third of the pitch in advance of 1, and the teeth of 3 one-
third of the pitch in advance of 2. We sometimes prefer to substitute this step
spur gearing by double belical gearing, in which case we mount upon the spindle a
right and a left hand helical pinion which gear into corresponding right and left
hand wheels on the second motion shaft.
Bearings. These may be of the construction usually adopted in dynamos and
similar machines. The bearings for the second motion shaft are preferably formed
in or carried by one of the pole pieces, preferably the lower pole piece L and in the
back standard V.
General. The details of the winding of the armature and of the field magnet
coils and other particulars of the machine will vary under different circumstances
but for an average case we will take a motor to produce about ten horse power.
In such a motor, the outside diameter of the armature core would be 9 inches and
seven-eighths and it would have 24 longitudinal grooves in its periphery for the coils.
The winding consists of 144 turns of copper wire 144 mils. diar. covered with cotton
to 162 mils., twelve turns of wire in four layers in each section. The winding is
covered with a continuous layer of soft charcoal iron wire of one-sixteenth inch
diameter wound on at right angles to the grooves containing the conductors.
The pole pieces to be bored out to ten and three sixteenths of an inch in diar.
Each field magnet is to be wound with five layers of copper wire 192 mils. diameter
covered with cotton to 210 mils., thirty-eight turns to each layer.
The flexible copper leads from the brushes to the terminals to have 130 wires
14 mils. diar. braided with double cotton.
The inter-connection of the terminals to be made with copper wire not less than
210 mils, diar.

page_text: Length of armature spindle, three feet four inches and three-eighths.
Length over armature core, ten inches. Grooves for the winding an inch at the
top and a quarter of an inch at the bottom and half an inch deep.
Pinions 15 teeth, wheels 45 teeth, six inches and five-eighths between centres.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed, we declare that what
we claim is :-
(1) An electro motor constructed and arranged substantially as hereinbefore
described with reference to the accompanying drawings.
(2) In the armature of an electro motor, V grooves for containing the conductors
and a continuous layer of iron wire thereon, substantially as and for the purpose
hereinbefore described, and as illustrated by the accompanying drawings.
(3) In an electro motor; the combination and arrangement of gearing for reducing
and transmitting the motion of the armature spindle to an auxiliary shaft, such
gearing consisting of two or more spur wheels and pinions arranged to break pitch
with each other or alternatively of two pairs of helical wheels and pinions one of these
wheels and pinions having a right hand and the other a left hand pitch; substantially
as hereinbefore described.
Dated this 27th day of July & D 1880
WILLIAM E. HEYS,
Agent for the Applicants.