IMPROVEMENTS IN MAGNETO-ELECTRIC MACHINES
Year: 1876

page_text: LETTERS PATENT to Herbert John Haddan, of the Firm of Herbert and
Company, Patent Agents, of 67, Strand, in the City of Westminster, Civil
Engineer, for the Invention of "IMPROVEMENTS IN MAGNETO-ELECTRIC
MACHINES." A communication from abroad by Edward Weston, of Newark,
Essex County, State of New Jersey, United States of America.
COMPLETE SPECIFICATION filed by the said Herbert John Haddan at the
Office of the Commissioners of Patents on the 6th November 1876.
HERBERT JOHN HADDAN, of the Firm of Herbert and Company, Patent Agents,
of 67, Strand, in the City of Westminster, Civil Engineer. "IMPROVEMENTS IN
MAGNETO-ELECTRIC MACHINES." A communication from abroad by Edward Weston,
of Newark, Essex County, State of New Jersey, United States of America.
My Invention relates to improvements in magneto-electric or dynamo-electric
machines, as will be herein-after more fully set forth.
In the accompanying Drawing,-
Figure 1 is an end view of my machine.
Figure 2 is a vertical cross section through the centre from end to end.
Figure 3 is an enlarged side view of the commutator; Figure 4 is a transverse
cross section through the same.
Figure 5 is a side elevation of an automatic switch which I use in this class of
machines; Figure 6 is a detailed view of a part thereof.
Figure 7 is a side view of an improved magnet also used in my machine; Figure 8
is a section of the same.
The first part of my Invention consists in improvements in that class of electrical
machines in which the power from an engine or other motor is utilized and trans-
formed into electricity, such machines being generally called " magneto-electric
machines." It further embodies in it the discovery made by Wheatstone of the
principle of mutual accumulation, that is, the current generated by the revolving
armatures is used to excite a stationary magnet, the latter being in circuit with the
current from the armature; but such discovery was only practically applied in
machines. where one electro-magnet was used, or else where a number of electro-
magnets were used,. the current from only a portion of the whole. number of

page_text: +
revolving armatures was used to excite the electro-magnets, the remainder being
used for any desired purpose, thus making a machine in which there were practically
two circuits.
In my improved machine the currents generated in a number of revolving
armatures are passed through the stationary magnets, involving a peculiar construc-
tion, differing widely from that adopted in the machines which up to the present
time have utilized the discovery of Wheatstone.
An iron ring or cylinder A is properly supported, the size of the ring depending
upon the size of the machine. From the interior of this ring a number of radially
projecting magnets B, B, are arranged, all pointing towards a common centre,
which magnets I prefer to make broad transversely and short radially. The
magnets B, B, are wrapped or wound with wire or ribbons b, b, in the manner
usually employed in making electro-magnets, and I may also wrap in the same way
the ring or cylinder A, to which the magnets are connected, as at a, a, such wrapping
increasing the effectiveness of my apparatus, and adding to its power. In the central
space left between the inward ends of the magnets B there is arranged a shaft C,
carried by suitable bearings D, D, and having upon such portion of it as is within
the ring or cylinder A a series of armatures E, E, all connected to an iron hub or
centre F. The armatures are of iron, and are also wrapped with wire or with
ribbons of metal, as at G, G.
The outwardly projecting ends of these armatures E, E, are so arranged as that
when they are simultaneously revolved by the turning of the shaft C their out-
wardly projecting ends will pass closely but without touching the inwardly
projecting ends of the magnets B, B. Thus when the shaft C is revolved, carrying
the armatures E, E, very rapidly past the electro-magnets B, B, currents of electricity
will be induced in the wires surrounding the armatures, but as such currents are
constantly changing in each armature from positive to negative the well-known
device called a "commutator" or "pole changer" has to be used. Such commu.
tators or pole changers when used in connection with a number of revolving
armatures have heretofore been constructed with the requisite number of separate
insulated strips, and with an equivalent number of springs or brushes, half of
which number are or always should be in connection with the armatures having
the negative or positive electricity, as the case may be, at the same moment, and
the currents transmitted by each spring is sent to the binding post or screw cup, or
the currents from the various springs join before reaching the screw cup or binding
'post.
Commutators have always been provided with as many springs or brushes as
*there are strips, which is a cause of loss, for the connection made is not always
perfect, and the metal is soon destroyed by the action of the current, or worn away,
thus necessitating a frequent renewal or adjustment.
In my improved form of commutator (seen at H, H,) all the strips which convey
currents of like kinds are united in the commutator itself, and therefore it is only
necessary to use the springs or brushes to collect the currents from all the arma-
tures, no matter how many magnets or armatures may be employed.
My pole changer or commutator is made in two parts, H and H. One part H
is slipped upon the shaft C, but is perfectly insulated from it, and also from the
other part of the commutator, both parts revolving with the shaft on which
they are mounted. An adjustable clamping ring J is placed upon the shaft, and
serves as an abutment at one end, while a nut K is screwed on the shaft at the
other end, and serves to keep the two parts of the apparatus together. Each part
is constructed as shown in the Drawing. The number of projecting pieces which
enter into spaces formed in the other half, but which do not touch or make in any
way a metallic connection between the halves H and H¹ correspond with the
number of rotating magnets forming the armature.
Only two springs or brushes are required with this form of commutator, as seen
at L and L. One is always in connection with one of the projecting pieces of the
one half, while the other is always in connection with the other half of the cominu-

page_text: tator, one spring always carrying or transmitting the positive currents, while the
other transmits the negative current.
The operation of this part of my Invention is as follows:-When the apparatus is
first made the stationary electro-magnets are for a moment put in connection with
a battery or other source of electricity, and after this they always retain a small
amount of residual magnetism. The belt from the engine, for example, being put
upon the pulley M. the armatures are put in rapid revolution, and a weak current
of electricity is produced, which flowing through first one half of the commutator,
and then the other half, as the case may be, is passed through suitably arranged
connecting wires N, N¹, to the coils b, b, which surround the magnets B, B, and if
desired through the coils a, a, surrounding the iron ring A. This circuit, small at
first, will rapidly excite the magnets B, B, producing the maximum effect. The
:current, after passing through the coils b and a, flows through any desired circuit,
the wire being led from the screw cup O; then, to complete the circuit, it returns
to the machine at the screw cup P, up through the spring or brush L into first one
half of the commutator, and then into the other, as the case may be, completing in
this way the circuit from the coils G surrounding the revolving armatures E, then
back again to these coils, having during its passage been utilized for any purpose
to which electricity is or may be applied, and in its passage exciting the stationary
electro-magnets B, B.
One-half of the number of coils which compose the armature are connected with,
for example, the part H of the commutator, and the remainder with the part H¹ of
the commutator, for half of the separately wrapped armatures are positive, and the
other half negative alternately.
Such arrangements are well known, and need no description. The size of wire
or ribbon used, the speed of revolution of the armature, and the coils G, G, should
bear approximately certain relations one to the other, but as such matters do not
.enter into any part of my Invention, and are within the knowledge of those having
to do with electrical apparatus, I will not enter into detail explanations.
It is to be specially observed, as it is a part of my Invention, that the entire
current generated in or by all the coils G, G, of the revolving armature is passed
through the coils surrounding the ring or cylinder A, and that none of the armatures
are set apart specially for the purpose of generating a current whose sole duty it
shall be to excite the magnets B, B.
When this class of machines are used for any purpose it is necessary to place the
work in circuit with the armatures and electro-magnets, so that the currents
induced in the armatures may pass through the external circuit, and through the
:coils of the electro-magnets. This gives rise to a very serious and troublesome
difficulty when the machine is used for the purpose of electro-deposition. If the
two wires leading from the electrodes immersed in a solution, which has been
undergoing electrolysis for a short time, be placed in connection with a galvanometer
a powerful current will be indicated, but the direction of the current will be the
reverse of the original current. This current results from what is commonly known
as polarization of the electrodes. Suppose that a dynamo-electric machine be
connected to the electrodes as above, and the machine is started, the solution will
undergo electrolysis, and the electrodes will become polarized; now if the machine
be stopped it is evident that the current resulting from the polarization will flow
through the armature and electro-magnets, and being in the opposite direction from
the original current it will reverse the polarity of the electro-magnets, and when
the machine is again started its current will flow in the opposite direction.
In using such machines for practical plating I have found that the polarity of the
magnets is changed before the machine stops, the reverse current from the vats
overcoming the feeble current produced by the machine at the slower speed, and
flowing through the coils of the electro-magnets reverses their polarity. If such a
machine be used for the purpose of electro-plating or electro-typing it can easily be
seen that if the ploarity of the magnets change by reason of the machine being
stopped or run too slow, when the machine is started again, the current being

page_text: reversed will dissolve the metal which has previously been deposited upon the
articles in the vat, and even the articles themselves would be seriously injured, in
most cases spoiling the work, and often the solution also.
The object of the second part of my Invention is to overcome this difficulty in a
simple and reliable manner. The reverse current from the vat is powerful, but it is
rapidly exhausted if it be put on short circuit; if the circuit between the vats and
the machine be broken before the machine reaches too slow a speed the polarity of
the magnets will remain unchanged, but it is necessary also that the machine
should reach a certain speed before the circuit between the vats and machine be
completed, otherwise the polarity of the magnets will be changed and the current
reversed.
The apparatus which is represented in Figures 5 and 6, and which I shall now
proceed to describe, accomplishes these purposes automatically and certainly, and is
capable of being easily adjusted to make and break the circuit at any desired speed.
A represents a pillar of brass, iron, or other conducting material, into which a steel
pin B¹ is driven, upon this pin a cup C¹, with stem Ď¹, and pulley E¹, is made to
rotate by means of a belt leading from the shaft of the machine or from any other
source of motion. This cup has ribs or flanges a¹, a¹, on the inner side of the
lower half, as shown in Figure 6. At a little distance from the pillar A¹ another
pillar G is placed standing vertically and parallel with the other, but the upper
part of this pillar is bent at or about right angles so as to project a little way over
the centre of and above the cup C¹, as shown in Figure 5. A hole is drilled near
the end of this pillar in a line with the axis of the cup C¹, and through this is
passed a wire b¹; another hole is drilled at right angles to this one and tapped, and
a small set screw d' is inserted, so that when screwed up it bears upon the wire b¹.
and holds it at any given height.
The pillars A, G, may be fastened in any suitable manner to a piece of wood or
any other insulating material, or fastened in any way to the base of the machine.
The wire 6 is cleaned and amalgamated with mercury, and a small quantity of
mercury is poured into the cup C₁. The wire 6¹ is now adjusted, so that it touches
the mercury in the cup.
It is evident that as long as the cup C¹ remains stationary the mercury will
remain at the bottom, and the wire b and cup C¹ will be in metallic connection,
but if the cup C₁ be rotated at a certain speed the mercury will rise in the cup, and
the connection between the wire and the cup will be broken. Supposing now that
the two wires ¹, ¹, from the machine are connected with the apparatus, one wire to
each pillar, and the machine started, the current will flow up the pillar A¹ through
the mercury, up the pin b¹, and down the pillar G¹ to the other wire, and back
again to the machine, thus completing the circuit, in fact the circuit would be
closed. But suppose the cup C₁ containing the mercury was caused to rotate by
means of a belt running from the shaft of the machine, then it is obvious that when
the machine, and consequently the cup, has reached a certain speed the connection
would be broken, the circuit opened, and the current could flow through an outside
conductor if it was connected to the two outside pillars conversely. When the
machine, and consequently the cup C₁, falls to a certain speed the connection
between the cup and pin b¹ would again be completed, and the current would cease
to flow into the external conductor, such as an electro-plating vat. It is plain,
therefore, that the reverse current could not flow through the coils of the electro-
magnets, but would flow through the mercury and would soon be exhausted.
By a slight modification this apparatus may be made to close the circuit between
the vats and the machine when the machine reaches a certain speed, and break it
again when it falls below that speed. I prefer to do this in the case of large
machines which, when they are on closed circuit with small resistance, require
considerable power to start them, and there is great danger of the belt running off
before they reach the speed necessary to open the circuit and break the connection
by the mercury rising and leaving the pin b¹. In this case it is necessary to use
.a wire with a disk of metal slightly smaller than the largest point of the inside of

page_text: the cup C, so that when the cup revolves and the mercury rises it will touch the
disk, and when it falls again the connection will be broken. In order to use this
arrangement it is necessary to connect one of the wires proceeding from the machine
to one of the pillars, and the other pillar is to be connected to a binding post to
which a wire leading from one of the electrodes of a vat may be attached. The
other wire from the machine is connected directly to the other electrode in the vat,
or more conveniently to a binding post on the base of the machine to which a wire
may be attached at any time. With this arrangement the circuit between the
machine and the vat is not closed until the machine reaches a certain speed, which can
be varied by raising or lowering the disk, and the connection is again broken before
the machine falls below a certain speed, thus preventing the reverse currents from
the vat passing around the electro-magnets and changing their polarity.
I do not limit myself to this particular device for opening or closing the circuit,
as various arrangements based upon the rotation of a mass or masses of metal may
be made to answer the same purpose; for instance, the mercury may be dispensed
with and a small governor similar to those which are used for steam engines may
be used; the balls, expanding and contracting at varying speeds, may be made to
open or close the circuit in various ways; by a slight modification this or a.
similar arrangement may be directly attached to the shaft of the machine instead
of using a belt or other mode of transmitting the power.
In first starting a dynamo-electric machine it is necessary to slightly charge the
electro-magnets of the machine either by means of a current of electricity from
some source, or in any other way to make them slightly magnetic. After this the
slight amount of residual magnetism is sufficient to excite the machine. This
residual magnetism is, however, insufficient to prevent the reverse current from
the vats changing the polarity of the electro-magnets should the current from the
machine become weak from any cause, such as a bad connection. To obviate this
difficulty is the object of the third part of this Invention, as shown in Figures 7
and 8. A² represents the iron core of an ordinary electro-magnet, on each side of
which is fastened a hardened steel plate B, and around this the wire C is wound in
the usual way.
I have found by experiments that if one or more of the cores of the electro-
magnets be made of steel, or if the iron cores have united to them in any suitable
way, one or more hardened steel plates, as represented in Figures 7 and 8, that the
reverse current resulting from the polarization of the electrodes cannot change the
polarity of the electro-magnets when the machine is running, thus preventing the
loss of time and the danger of spoiling the work and solution consequent upon the
reversal of the current.
In carrying out this part of my Invention, although a steel core answers the
purpose very well, yet I prefer to use one or more hardened steel plates on the
outside of the iron core, and around which the wire is to be wound in the usual
way; but I do not confine myself to this particular way, as it is obvious that the
same effect may be obtained in a variety of ways.
Having thus fully described my Invention, what I claim as new and desire to
secure by Letters Patent is,
1st. In a magneto-electric machine a ring of iron or other magnetic material,
wrapper or unwrapped, having radially projecting magnets attached to or forming
a part of such ring.
2nd. In a magneto-electric machine having but one circuit, the combination of
a ring of iron or other magnetic material, wrapped or unwrapped, and having
a series of radially projecting magnets attached to or forming a part of such ring,
with a hub or centre of iron or other material, having projecting from it a series of
wrapped armatures attached to or forming a part of such hub.
°
3rd. A magneto-electric machine with radially projecting electro-magnets and
radially projecting armatures, when arranged so that the current generated in all
the armatures is passed around the radially projecting electro-magnets, substantially
as and for the purposes set forth.

page_text: 4th. The commutator H, H³, made in two parts, as described, placed upon the
shaft C, the clamping ring J and nut K, all constructed substantially as and for
the purposes set forth.
5th. In a dynamo-electric machine, an adjustable switch operated or controlled
by means of a revolving shaft for opening or closing the circuit between the
machine itself and an external conductor, the whole being arranged to open the
circuit between the machine and the external conductors when the speed of the
machine falls to a certain point.
6th. The method of making and breaking the current between a dynamo-electric
machine and an external conductor by means of a revolving shaft, a mass of
mercury, and an adjustable piece of metal, substantially as herein set forth.
7th. In combination with a magneto-electric machine a switch operated or con-
trolled by means of a belt or other mode of transmitting power, a revolving shaft,
and an adjustable wire or other piece of metal, the whole being arranged to open
the circuit between the machine and the external conductor when the speed of the
machine falls to a certain point.
8th. In a dynamo-electric machine an electro-magnet composed partly or entirely
of steel, for the purpose of preventing the reverse current from the electrodes
changing the polarity of the electro-magnets, as set forth.
In witness whereof, I, the said Herbert John Haddan, have hereunto set my
hand and seal, this Fourth day of November, in the year of our Lord One
thousand eight hundred and seventy-six.
H. J. HADDAN. (L.S.)