IMPROVEMENTS In ELECTRICAL MOTORS
Year: 1885

page_text: ROBERT ABRAM LEE 76 High Holborn Lon-lon W.C. Electrical Engineer JOHN
EDLINGTON CHASTER 1 Poyning's Road Junction Road, London Ñ. Electrical
Engineer do hereby declare the nature of our invention for IMPROVEMENTS In
ELECTRICAL MOTORS, to be as follows:-
:-
The object of this invention is the improvement in the construction of electrical
motors by the hereinafter described means,
Electrical motors as hitherto constructed have required a high rate of speed in
running to give a good efficient mechanical return of power for the electrical energy
absorbed by said motors. This high rate of speed being in most cases objectionable
owing to intermediate gearing being required for utilizing the power to existing
machinery; which intermediate gearing wastes power through loss by friction.
We find that by constructing the revolving armature of considerable diameter in
proportion to its width in combination with the improved field magnets hereinafter
described, we obtain electrical motors giving a much lower speed whilst at the samo
time having a high electrical efficence that is to say the motor is capable of giving
out a very large percentage in mechanical power of the electrical energy passed into
the same.
This holds good as well with small motors as.with large.
To secure these hereinabove mentioned advantages, the armature is a ring form
made in the softest iron. It is divided into G or more equal divisions which
divisions are parellel in themselves, and at right angles to the centre of motion,
and upon which the necessary wire is wrapped. One of the several features is that
the divisions that are opposite have parellel sides, that is the outside and inside
edge of the ring are parellel with themselves & likewise parellel to the two sides of
the division opposite, thus allowing the wire that is wrapped thereon to be very
evenly laid coil upon coil. The coils of wire on each section are also stepped off
each other so that a considerable air space is left between one section of wire and
its neighbour thus allowing a free ventilation which prevents the motor from
becoming heated.
The air spaces may be replaced and lugs of iron wrought or cast thereon, the
sides of which are at right angles to the sides of the armature, the depth of these
lugs are the same as the thickness of the wire wrapped on the armature so that
when revolving between the poles of the field magnets the coils of wire together
with the lugs of iron between only just clear the pole pieces of the said field
magnets.

page_text: .
The inside ends of the lugs between the several coils on the armature are
screwed on to the edge of a brass flange in the centre of which is a boss allowing
the whole armature to be keyed on to the shaft.
The field magnets are upright round pillars two of which are fixed on either side
of the armature. The ends of these field magnets are braced together by the pole
pieces at the top & bottom and at right angles to the said field magnets. The pole
pieces at the ends of the field magnets have opposite polarity. The same is on
either side of the armature so that the said armature runs between the four pole
pieces. The pole pieces on the top are of like polarity & those at the bottom are
of like polarity to each other, but of opposite polarity to those on the top. We
also find it advantageous to use a new & improved form of electrical connection
between the field magnets & brushes so that if a handle be carried from the one
end of the brush holder we can by throwing over the handle to the opposite side
reverse the motion of the electrical motor & stop the action altogether when mid-
way between the two extreem limits of the throw of the arm carrying brushes.
To effect this we utilize the part of the arm before referred to, carrying the handle
which makes contact with two insulated springs when moved through the extreem
limits which is allowed the arm, but insulated from the bed plate of the machine
from which it is carried, as is also the portion of the arm that makes contact with
aforesaid spring, but in electrical connection with one of the commutator brushes.
The electrical connection is broken when the arm of carrying brushes is placed
midway between the two extreem limits of movement hence the motor stops. We
thus obtain by one movement starting, stopping and reversing gear.
ROBERT ABRAM LEE Electrical Engineer 76 High Holborn and JOHN EDLINGTON
CHASTER Electrical Engineer 1 Poynings Road Junction Road London N. do hereby a
declare the nature of our invention for IMPROVEMENTS IN ELECTRICAL MOTORS
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
The object of this invention is the improvement in the construction of electrical
motors by the hereinafter described means. Electrical motors as hitherto con- 3
.structed have required a high rate of speed in-running to give a good efficient
mechanical return of power for the electrical energy absorbed by said motors.
This high rate of speed being in most cases objectionable owing to intermediate

page_text: gearing being required for utilizing the power to existing machinery; which
intermediate gearing wastes power through loss by friction. We find that by
constructing the revolving armature of considerable diameter in proportion to its
width in combination with the improved field magnets hereinafter described we
obtain electrical motors giving a much lower speed whilst at the same time having
a high electrical efficiency that is to say the motor is capable of giving out a very
large percentage in mechanical power of the electrical energy passed into the same.
This holds good as well with small motors as with large. To secure these above
mentioned advantages the armature is a ring form made in the softest iron. It is
divided into six or more equal divisions which divisions are parellel in themselves
and at right angles to the centre of motion, and upon which the necessary wire is
wrapped. One of the several features is that the divisions that are opposite have
parellel sides, that is the outside and inside edge of the ring are parellel with
themselves and likewise parellel to the two sides of the division opposite, thus
allowing the wire that is wrapped thereon to be very evenly laid coil upon coil.
The coils of wire on each section are also stepped off each other so that a consider-
able air space is left between one section of wire and its neighbour, thus allowing
a free ventilation which prevents the motor from becoming heated. These air
spaces may be filled by lugs of iron wrought or cast thereon; the sides of these are
at right angles to the sides of the armature; the depth of these lugs are the same
as the thickness of the wire wrapped on the armature, so that when revolving
between the poles of the field magnets the coils of wire together with the lugs of
iron between only just clear the pole pieces of the said field magnets. The inside
ends of the lugs between the several coils on the armature are screwed on to a brass
flange in the centre of which is a boss allowing the whole armature to be keyed on
to a shaft. The field magnets are four upright round pillars two of which are fixed
on each side of the armature. To the ends of these field magnets are fixed the
pole pieces, these pole pieces being at right angles to the field magnets. The pole
pieces at the upper end of the field magnets have opposite polarity to those at the
lower ends.
Electrical connection between the commutator and the field magnets is made
by means of a pair of brushes which are attached to a brush holder of peculiar
construction, so made that it serves for the purpose of reversing or stopping the
motion of the armature by simply turning a handle fixed thereto, through an angle
of 180° or 90°.
This brush holder consists of a ring having two arms at its opposite side. (This
ring is carried on a projecting part of one of the bearings which projection serves
as an axis for the ring.)
To the outer part of each of these arms is fixed a contact brush, which consists
of a strong brass spring insulated from the metal of the arm which carries it, but
connected to a friction knob or spring on the end of the arms, the friction knobs or
springs make contact with two upright springs, one of these is connected to a
terminal for the battery wire, the other to the wire from the field magnets.
Therefore when the ring is so placed that its arms are horizontal, the current
passes from the battery to one of the upright springs thence through the brush and
commutator to the wire on the armature, after passing through this it courses
through the other commutator brush, and the other upright spring, to the wire on
the field magnets leaving which it passes back to the battery.
If the handle by which the ring is moved be turned through an angle of 180°
from the position it previously occupied, the current takes an opposite course, that
is it passes through the wire on the arinature in an opposite direction to that which
it previously pursued, so that the motion of the armature is reversed. When the
arms are in a vertical position electrical connection ceases and the motion of the
armature is stopped.
Referring to the accompanying drawings Fig. I is a front elevation and Fig. II a
section through the centre of Fig. I when viewed endways. Fig. I and Fig. II
P. P. P. P. are the magnets and pole pieces between which the armature A,

page_text: revolves. The armature is bolted to a brass plate B, baving a boss which is keyed
or pinned to shaft S; C is the commutator brush holder, this is shown in Fig. I,
in a horizontal position; where it makes connection with the insulated springs I, I,
through which the current proceeds completing the electrical circuit.
When in
this position the armature revolves always in one direction.
If the handle H, of
the commutator brush holder be moved round to the other side so that the contact
portions of the brush holders make connection in an opposite manner, the armature
revolves in an opposite direction to which it did in the first instance. Should the
handle be moved up to its highest point and midway between the two positions as
described above, the armature will not revolve, owing to the electrical circuit being
broken as previously described. The commutator is thus shown in the sectional
drawing Fig. II, where G, G, are not in electrical-connection with I, I. The field
magnets P, P, P, P are bolted down to a brass or other non-magnetic bed plate T,
as shown at W, by means of studs and nuts from underneath. The shaft S, carries
a wooden or other pulley V, keyed thereon. All the electrical of the field magnets
are made underneath the base plate or bed T. The end of one wire from the field
magnets is brought to one binding screw; and the one end of the wire from the
armature through one of the connecting springs I, to the other binding screw.
These binding screws are not shown in the drawing, but these said binding screws
may be placed on either the base plate or where convenience may require.
Having now particularly described and ascertained the nature of our said
Invention, and in what manner the same is to be performed we declare that
what we claim is
1st The arranging the armature and field magnets as described.
2nd Arranging commutator, insulated springs and handle as set forth.
3rd The general combination as herein described.
Dated this 22nd day of October 1885.
ROBERT ABRAM LEE.
JOHN EDLINGTON CHASTER.