IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES OR ELECTRIC GENERATORS
Year: 1882

page_text: LETTERS PATENT to Sebastian Ziani de Ferranti of Richmond Gardens
Shepherds Bush Electrician and Alfred Thompson of Guildford Place Russel
Square Floatricion both in the County of Middlesex
for
LETTERS PATENT to Sebastian Ziani de Ferranti of Richmond Gardens
Shepherds Bush Electrician and Alfred Thompson of Guildford Place Russel
Square Electrician both in the County of
invention of
IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES OR ELECTRIC GENERATORS.”
Middlesex for 03
De County ΟΙ Middlesex for on
IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES OR ELECTRIC GENERATORS."
"
INTROVEMENTS IN DYNAMO-ELECTRIC MACHINES OR ELECTRIC GENERATORS."
PROVISIONAL SPECIFICATION left by the said Sebastian Ziani de Ferranti
and Alfred Thompson at the Office of the Commissioners of Patents on the
18th July 1882.
SEBASTIAN
ZIANI DE FERRANTI of Richmond Gardens Shepherds Bush
Electrician and ALFRED THOMPSON of Guildford Place Russel Square Electrician
both in the County of Middlesex "IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
OR ELECTRIC GENERATORS ,,
This invention has for its object improvements in dynamo electric machines or
electric generators.
A well known method for the production of alternating currents is by means of
bobbins of insulated wire set around the periphery of a wheel which is caused
rapidly to rotate and to carry the bobbins between the poles, alternately north and
south of electro-magnets ranged around the wheel. Then as each bobbin approaches
the pole of any magnet a current is set up in the coils of the bobbin and as the
bobbin leaves the pole a current is set up in the opposite direction. By suitable
means these currents are led into a main or outside circuit.
Now for the separate winding of these several bobbins we substitute one single
conductor, passing in an undulating form around the wheel.
rest this conductor may be traced in a zigzag direction, first outwards from the
With the wheel at
centre of the wheel between two adjacent poles of the fixed magnets, then returning
inwards towards the centre between one of these poles and the pole of a third
magnet and so on until the circuit is complete. The ends of the zigzag conductor are
connected with the outside circuit-The zigzag conductor is bolted firmly to the
wheel, so that the construction is both simple and solid.
Or in place of this single zigzag conductor, we may employ a coil of insulated
wire or other conductor, such wire or conductor taking a like zigzag course but
passing many times around the wheel before the end is brought out to be connected
with the outside circuit. The insulated conductor may be first wound in the form
of a hoop and then bent, by suitable tools into the zigzag form.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Sebastian Ziani de Ferranti and Alfred Thompson in the Great Seal
Patent Office on the 18th January 1883.
SEBASTIAN ZIANI DE FERRANTI of Richmond Gardens, Shepherds Bush,
Electrician and ALFRED THOMPSON of Guildford Place Russell Square Electrician
"IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
both in the County of Middlesex
OR ELECTRIC GENERATORS
"
A well known method for the production of alternating currents is by means of
bobbins insulated wire set around the periphery of a wheel which is caused
rapidly to rotate and to carry the bobbins between the poles, alternately north and
south of electro magnets ranged around the wheel and on either side of it with the
poles alternately north and south. Then as each bobbin approaches the pole of any
magnet a current is set up in the coils of the bobbin, and as the bobbin leaves the
pole a current is set up in the opposite direction. By suitable means these currents
are led into a main or outside circuit.
Now in place of using bobbins it has lately been proposed by Sir William
Thomson to substitute one single conductor of copper or such like metal passing
with very numerous corrugations in an undulating form around the wheel and
bound down to it by a binding passing round the wheel and outside a series of
pins which lie in the hollows or undulations of the zig-zag conductor.
It has also been proposed by Dr John Hopkinson to use single conductors
wound in a zig-zag manner between iron studs or pole pieces projecting out from
the side of the revolving disc or wheel. We use no iron pole pieces but we employ
one single conductor passing in an undulating form around the wheel and according
to our invention we so form it that there shall be as many radial portions of the
zig-zag conductor as there are magnets on either side of the revolving wheel so
that if the wheel were at rest this conductor might be traced in a zig zag direction
first outwards from the centre of the wheel between the adjacent poles of the fixed
or field magnets on one side of the wheel then returning inwards towards the
centre between one of these poles and the pole of a third magnet and so on until
the circuit is completed. The field magnets are so arranged that the poles of the
several field magnets on one side of the wheel are alternately north and south and
so that a north pole of a magnet on one side of the wheel faces a south pole of a
On revolving the wheel each radial
magnet on the opposite side of the wheel
portion of the zig-zag copper conductor will as it is carried from the pairs of
opposite magnets north south to south north have electricity generated therein
centrifugally and centripetally from the pairs of magnets south north to north
south and so produce a continuous alternating current all the radial arms of the
conductor being at all times uniformly acted upon and the maximum effect so
obtained. Also according to our invention we firmly bolt or fix the zig-zag con-
ductor to the wheel in such manner that the centrifugal strain which is set up
when the machine is driven and which tends to separate the conductor from the
wheel, is not supported by a circumferential binding but is directly transmitted to
and is sustained by the body of the wheel.
Or in place of this single zig-zag conductor, we may employ a coil of insulated
wire or other conductor, such wire or conductor taking a like zig-zag course but
passing many times around the wheel before the end is brought out to be connected
with the outside circuit. The insulated conductor may be first wound in the form
of a hoop and then bent by suitable tools, into the zig-zag form.
In the winding of the field magnets also we cause the conductor to take a zig-zag
course amongst the cores arranged in a circle, and to pass alternately on the inner
and outer side of each core. The conductor thus forms a double zig zag or wicker work

page_text: in which the cores are enclosed. This method of winding whilst completely
enveloping the cores leaves interstices which facilitate the dissipation of heat.
Figure 1 of the Drawings hereunto annexed is a side elevation of a portion of
the wheel and zig-zag conductor of our dynamo electric machine.
Figure 2 is a transverse section and this view indicates the position of the
stationary field magnets.
Bolts
A is the axis and B is the wheel consisting of two rings of bronze keyed or
firmly fixed upon it. These rings are adapted as the Drawing shews to embrace
projections or feet formed upon the zig-zag bar conductor. The conductor C is of
copper, and to prevent metallic contact between the feet and the rings B the feet
are enveloped in wrappers of vulcanised fibre or other insulating material.
DD pass through lugs B' upon each of the rings and through the feet of the
zig-zag conductor and ensure the parts being securely held. The holes by which
the bolts pass are lined with insulating material to prevent metallic contact
between them and the conductor C.-Or in place of the bolts being passed through
lugs B¹ they might be passed through the rings at a point between the feet of the
conductors and the axis.
The position of the field magnets E in respect to the moving parts is indicated
in Figure 2 some of the magnets are also shewn in Figure 1. In the machine
represented there are sixty four such magnets thirty two on either side. They
are shown as being wound in the ordinary manner, or they may be wound
according to our improved method herein after more fully described.
These field magnets may be excited by a continuous current machine of any
known type. In Figure 3, F represents an insulated ring which is provided upon
the axis A, and G is a lever which is caused to bear upon the ring by the coiled
spring H, the lever also is insulated from the frame of the machine, it is connected
with a binding screw which forms one of the terminals of the machine and the
other terminal is upon the frame. One of the ends of the zig-zag conductor may
be made fast to the body of the wheel in such a manner as to establish a good
electrical connection so that the current may pass from it to the wheel and to the
frane of the machine. The other end of the zig-zag conductor is kept out of
contact with the wheel and is secured to the insulated ring. A convenient
arrangement is to employ two insulated rings F one on either side of the wheel.
and to fork or divide the end of the zig-zag conductor and carry it down on
either side of the wheel to its attachments with the insulated rings in the manner
shewn at Figures 1 and 2. The two ends of the conductor are formed with feet
which are embraced between the two parts of the wheel B in the same way as
the other feet and to each end is bolted a conducting bar K one of these is con-
nected to one insulated ring and the other to the other insulated ring.
Figures 4 and 5 show a modification according to which the feet of the zig-zag
conductor are dovetailed and adapted to slide laterally into corresponding grooves
in the face of the wheel. The insulation of the feet is secured as before by
enveloping them in covers of vulcanised fibre or other insulator. Rings Lon
either side attached to the wheel by screws prevent the feet escaping from the
grooves, these rings are shewn at Figure 5-this figure also shows how that the
ends of the conductor may be led the one to one side and the other to the other
side of the wheel in order that each may be connected to an insulated ring on
the axis.
The zig-zag conductor C may be cast to the form required and subsequently
tooled and finished. It is important that the casting should be as uniform as may
be so that there shall be a uniform amount of metal in each cross section of the
conductor. It is also desirable that the metal should be as dense as practicable-
any known methods of obtaining dense copper castings may therefore be used
with advantage. The casting also might be compressed by a swage forced against
it by hydraulic pressure the swage may be of a size to act upon one section only
of the casting at one time. Or the zig-zag conductor might be cut or slotted or
punched out from a rolled plate of metal.

page_text: Figures 6 and 7 illustrate our arrangement when employing a zig-zag conductor
passing several times around the wheel. The conductor in this case may be a flat
band of copper, it is wound round and round into a circular hoop, one convolution
being separated from another by ribbons of silk. The conducting ring is then
bent to the zig-zag form and secured to the wheel. In this case we make the body
of the wheel of brass or other suitable metal and between this and the zig-zag
conductor we place a ring of wood and we recess the wood to receive the
undulations of the conductors. The attachment of the conductor is made by
means of metal lugs on either side of the zig-zag firmly bolted to the metal wheol
and by metal pins passing through these lugs and lying within the undulations
as the Drawing indicates. The ends of the copper band may be led down grooves
in the wooden wheel and attached the one to the axis and the other to an insulated
ring thereon.
Figure 8 is an end elevation of one half of a circle of field magnets having the
insulated wire or conductor wound upon them according to our invention in a
double zig-zag, or wicker fashion. Figure 9 is a side elevation of part of the pole
piece of one of the magnets with parts of the wicker work conductor which
embrace it. An advantage of this method of winding is that whilst each magnet
is completely enveloped in the winding interstices are nevertheless left which are
favorable to the dissipation of heat generated in the coils.
•
Having thus described the nature of our said invention and the manner of
performing the same we would have it understood that what we claim is:
First, Our improved dynamo electric machine with no iron armature pole
pieces but with a zig-zag conductor so formed that the radial parts of the zigzag
are at the same distance apart as the field magnet poles on either side of it
substantially as described.
Second. Our improved dynamo electric machine in which the armature consists
of a wheel encircled by a zigzag conductor bolted or attached to the wheel in such
manner as to transmit to the body of the wheel the centrifugal strain which arises
from the rotation of the zig-zag conductor and which tends to separate it from the
wheel.
Third. Our improved dynamo electric machine, in which the armature consists
of a wheel encircled by a zig-zag conductor formed by winding a wire or metal
band with suitable insulation round and round into a hoop, then bending the hoop
to a zigzag form, and attaching it to the periphery of the wheel.
Fourth. Our improved double zig-zag method of winding the field magnets of
dynamo electric machines.
In witness whereof I the said Alfred Thompson have hereunto set my hand
and seal this Seventeenth day of January in the year of our Lord One
thousand eight hundred and eighty three.
ALFRED THOMPSON (L.S.)