Improvements in Dynamos.
Year: 1898

page_text: Date of Application, 6th Dec., 1398 -Accepted, 11th Feb., 1899
COMPLETE SPECIFICATION.
Improvements in Dynamos.
I, JOHN EDWARD FULLER, residing at No. 201, East 45th Street, in the City
and State of New York, United States of America, Electrician and Manufacturer,
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 is especially intended for developing an electric current for
an incandescent lamp upon a cycle or carriage, the armature being driven by a
connection to one of the wheels. In consequence of the varying speed at which
the vehicle may be propelled, there is risk of too great a current being developed
and the lamp being injured, or else the current is insufficient for the lamp when
the vehicle is moving slowly.
In the present dyname, the parts are constructed with reference to producing
the current necessary for an incandescent lamp upon a cycle or carriage when the
vehicle is moving at a slow rate, and as the speed of the vehicle increases the
current developed is cut down in such a way as to avoid injury to the lamp by
too strong a current.
It is important in portable dynamos to obtain and maintain a uniformity of
magnetic polarity in all parts of the two poles of the field magnet, and to obtain
this result I separate such poles by incisions that are perpendicular to the axis
of the armature, and such incisions extend down the pole supports or legs or
base to the neutral point or about the place of no magnetism.
In the drawing, Figure 1 is a vertical section longitudinally of the armature axis
Fig. 2 is a plan view. Fig. 3 is an end view. Fig. 4 is a diagram illustrating
the circuit connections, and Fig. 5 shows the governor at the end of the armature
poles.
The field-magnet A is advantageously of the shape represented in Fig. 3, and
it is permanently magnetized at the poles N and S, the faces of which are arcs
of circles, and the armature B is made with a core 3 of soft iron, there being a
helix or coil of insulated copper wire C wound around the core 3 and between
the pole-pieces 4, 4, the outer faces of which pole-pieces are segments of
cylinders.
The armature shaft or arbor 5 at one end is supported by the cross piece 6 of
non-magnetic material between the pole-picces 4, 4, and the shaft 7 at the other
end is upon the similar cross-piece or head D, and the plate E is connected by the
screws 8 to the field-magnet poles, and it receives through it the shaft or arbor 5,
and this plate E is insulated from the magnet-poles and receives upon it the
binding-post F for one of the conductors passing to the electric lamp. and there
is a spring 10 extending from the binding-post and bearing against the shaft or
arbor 5, so that the circuit passes from this binding-post F and spring 10 and
shaft 5 to the cross-piece 6 and to the core of the armature B.
The shaft 7 which projects out from the head D of the armature is supported
by a plate G having screws 11 passing into the poles of the field-magnet, and
upon this shaft 7 is a pulley H which is preferably grooved deeply for the recep-

page_text: tion of a belt 12 or cord leading to the wheel that is revolved when the vehicle is
in motion, so that the armature is revolved by the belt 12 upon the pulley H
through the shaft 7 and head D.
The hub of the pulley H forms a continuous contact for the spring 13 that
passes to the binding-post I from which the other circuit wire passes to the
lamp, so that it will be seen that the external circuit is to the binding-posts F
and I, see Fig. 2, and from such binding-posts through the arbors or shafts, of
the armature.
The armature itself contains the coil C of insulated wire, the inner end of
which is advantageously connected to the core of the armature; and the head D
of the armature is insulated at its connections to the ends of the pole-pieces 4, in
order that the governor 0, which is carried by this head D), may regulate the
current set up in the circuit, as hereafter described.
The armature being of soft iron and having a coil or helix around it, becomes
an electro-magnet, and I find that when the governor is in the form of an iron
plate retracted by a spring from one end of the armature, the current developed
in the coil of the armature being in proportion to the speed of rotation, that when
the magnetic energy in the armature is sufficient to overcome the resistance of
the spring, the governor plate will be attracted by the magnetism in the armature
at one end thereof, and by coming into contact with the two armature poles,
the magnetism of the core and pole-pieces is reduced in proportion to the in-
timacy of contact of such governor, and the governor plate becomes a magnetic
neutral, so that the N and S polarity is alone manifested at the opposite, end of
the armature to the governor.
The strength of the spring carrying the governor can be varied or it can be
made with reference to a given current developed by the dynamo; and in addi-
tion to the governor changing the magnetism of the armature, such governor
may also be employed for throwing into the armature circuit a resistance to cut
down the current flowing through such armature helix.
The governor is long enough to extend across from one pole of the armature
to the other, and this governor is supported by a suitable spring upon the
cross-piece or armature head. This spring is represented at 15 in approxi-
mately the form of a horse-shoe, and the strength of the spring can be varied
by any suitable mechanism, and when the magnetism set up in the electro-
magnetic armature is sufficient to overcome the spring 15 and attract the ends
of the governor () against the projecting ends of the armature, the governor
plate coming into contact with such ends of the armature, acts like a keeper
or yoke between the two cores of an electro-magnet, and hence such governor
becomes neutral, leaving the N and S polarity at the other end of the body of
the armature, and the magnetic action of the armature upon the current set up in a
coil of such armature is cut down to the extent of contact of the governor or with
the ends of the armature and to the duration of the contact, so that when the
current is excessive and sufficient to attract the governor O and hold it into
contact with the ends of the armature, the magnetism of such armature is cut
down and the output of current proportionately lessened; and this governor O
will play back and forth upon the end of the armature with more or less rapidity,
because the magnetism will be cut down in the armature by the reduction of
current flowing through the helix of the armature.
Under most circumstances, this vibrating governor 0 is sufficient for regu-
lating the output of current according to the speed of the vehicle or the arma-
ture shaft; I, however, find it advantageous under some circumstances to pro-
vide a resistance in the form of a coil L of German silver or other wire, around
the armature so as to throw this resistance into the circuit of the lamp when-
ever the output of current is abnormal in consequence of increase in the speed
of the cycle or other vehicle.
The armature helix C is always in circuit, because the current passes from F
through 10 and 5 to the body of the armature, and through the insulated coils C

page_text: to the head D, and from thence by the shaft 7, pulley H and spring 13 to the
external circuit, and I connect the resistance coil L at one end to the wire of
the armature coil C, and the other end of the resistance L is connected with the
cross-bar ) and external circuit.
The spring 17 is insulated, and to the same the ends of the helix C and the
resistance coil L are connected, as indicated in Fig. 4, and the spring contact 16
is upon the cross-piece or head ; and in the ordinary position of use, the
spring 17 engages the spring 16, and short circuits the resistance coil L, but
when the governor 0, acting upon the spring 17 breaks the circuit connection
between 17 and 16, the current passes through the armature helix and through
the resistance helix L in series and thence to the cross-bar or head D, hence the
resistance L is thrown into series simultaneously with the breaking of the circuit
between 16 and 17, and by this arrangement and the proper proportioning of
the parts, according to the average speed of the vehicle, so the output of current
from the dynamo to the lamp will be sufficient for the illumination thereof and
without risk of injury by too strong a current.
As soon as the magnetism and the current developed in the armature are
sufficiently lessened, the governor springs back and the spring 17 closes the
circuit through the spring 16 and head D, short circuiting the resistance coil L,
and in so doing, the current set up by the revolution of the armature is augmented,
and by the play of the governor O back and forth, the voltage is regulated accord-
ing to the strength of the springs 15 and 17.
The guard disk 20 surrounds the arbor 7 of the armature and is adapted to
turn freely with the armature, and there is sufficient space between the guard
disk and armature poles for the governor to vibrate with freedom, but such guard
disk prevents the governor coming into contact with the plate or frame that
supports the arbor and armature.
It is important, especially in portable dynamos for vehicles, to obtain and
maintain a uniformity of magnetic polarity in the two poles of the field-magnet.
Where the pole-pieces are in one and are as wide as the length of the armature,
the greatest magnetism is usually developed near the ends of the pole-pieces
and where the wires of the armature coil, as they revolve, do not cut the lines of
magnetic force.
To avoid this difficulty and unify the polarity of the field-magnet, I separate
such poles by incisions that are perpendicular to the axis of the armature, and
such incisions extend down the pole-supports or legs or base to the neutral point
or place of no magnetism, or nearly so, in order that the solid portion 22 may
connect the N and S tongues or bars of the field-magnet and the incisions at 23
are advantageously made by a saw and are sufficiently near together to properly
divide up the pole-pieces N and S into bars that are approximately rectangular
in section, so that each bar may be magnetized to saturation either as a per-
manent magnet or as an electro-magnet; and by this construction, the expense
of the field-magnets much less than in cases where separate horse-shoe or other
magnets are joined together in a group, and each bar of the pole-pieces, in my
improvement, becomes uniformly magnetized and will retain such magnetism
and act to better advantage in the development of current by the wires of the
armature crossing the lines of magnetism between the pole-pieces, than in cases
where the pole-pieces are not divided up into sections.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what I
claim is
First The combination with the field magnet, of an armature having a core
and coil and an external circuit to a lamp, a governor at one end of the armature,
and a spring to draw back the governor, such governor acting to lessen the
magnetism in the armature when in contact with the poles thereof, substantially
as set forth.

page_text: Second: The combination with the field magnet and armature in a dynamo,
of a governor adjacent to the ends of the armature, a spring to draw such
governor away from the armature, a resistance coil around the armature and a
circuit connection controlled by the governor for throwing the resistance coil
into series with the armature coil when an excess of magnetism is developed in
the armature, substantially as set forth.
Third: The combination with the revolving armature, of field-magnet pole-
pieces integral with a common connecting base, but divided up into similar
sections at the respective poles, whereby a uniformity of magnetism is set up
and maintained in the poles of the field-magnet, substantially as set forth.
Fourth: The combination with the field-magnet, of an armature having a
core and coil and a resistance coil connected in series with the armature coil, a
spring contact to short-circuit the resistance-coil, and a governor acted upon by
the magnetism of the armature to break the short-circuit and throw the resistance
into the armature circuit when the magnetism of the armature becomes abnormal,
substantially as set forth.
Fifth In a dynamo, the combination with the field-magnets having seg-
mental faces, of an armature core and coil, a cross-bar and shaft at one end of
the pole-pieces, an insulated head, an arbor at the other end of the pole-pieces,
a governor adjacent to the pole-pieces of the armature and an insulated spring
for supporting the same, and a spring contact and resistance in a branch circuit,
whereby the resistance is thrown into series with the armature coil when the
branch circuit at the spring contact is broken, substantially as set forth.
ERNEST DE PASS,
Chartered Patent Agent, 78, Fleet Street, London, and
5A, Market Street, Nottingham, Agent for the Applicant.