IMPROVEMENTS IN DYNAMO ELECTRICAL MACHINES
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
We Sir WILLIAM THOMSON, Knight, of Glasgow College, Doctor of Laws and
Professor of Natural Philosophy in the University and College of Glasgow in the
County of Lanark North Britain and SEBASTIAN ZIANI DE FERRANTI of 5 Stanwick
Road, West Kensington in the County of Middlesex Electrician do hereby
declare the nature of our invention for "IMPROVEMENTS IN DYNAMO ELECTRICAL
MACHINES to be as follows :-
"
In dynamo machines for producing alternating electric currents the currents
induced in the conductor of the revolving armature are sometimes led off through
two insulated conductors carried by the armature axis.
One of these conductors has also been coupled to one insulated ring surrounding
the axis and the other conductor to another insulated ring surrounding the axis
and the current has been led off from the insulated frings by metallic brushes or
rubbers made to bear upon them.
In place of thus leading off the current from the insulated rings we form each
ring with a disc projecting outwards around it. We surround the outer part of
each disc with a fixed ring which is U shaped in cross section making the two sides
of the U shaped ring to come on the two sides of the disc with a slight spaco
hetween them. These U rings stand vertically as the armature axis is horizontal
as is usual. The lower part of the ring we fill with mercury and we also spread
out the mouth of this lower part of the ring to make it serve as a reservoir or wo
lead a pipe from it to a reservoir in any other convenient position.
When the axis is revolved the mercury is caused to spread itself uniformly all
around the circumference of the trough ring and form a conductor from all parts of
the circuinference of the disc to the ring.
We also lead a pipe upwards from the top of the ring up into which some of the
mercury will be driven when the axis is revolved-the distance it rises in the pipe
will depend on the speed of revolution.
The portion of the disc which is nearest to the axle we make thicker than the
outer portion of the disc and around the shoulder where the change in thickness
takes place we form a V groove. When the disc ceases to revolve the mercury
within the trough ring and the pipe which rises from it will drop into this groove
and will flow down it into the lower part of the trough ring and so into the
reservoir which branches from it. This reservoir may be closed over and a pipe be
led from it to a funnel through which it may be supplied with mercury.
The axis we make hollow and carry the conductors through it concentrically one
within the other.
Dated this 00nd day of March 1981

page_text: We, Sir WILLIAM THOMSON, Knight, of Glasgow College, Doctor of Laws and
Professor of Natural Philosophy in the University and College of Glasgow in
the County of Lanark North Britain and SEBASTIAN ZIANI DE FERRANTI of
5 Stanwick Road West Kensington in the County of Middlesex Electrician do
hereby declare the nature of our invention for "IMPROVEMENTS IN DYNAMO
ELECTRICAL MACHINES and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
In dynamo machines for producing alternating electric currents the currents
induced in the conductor of the revolving armature are sometimes led off through
two insulated conductors carried by the armature axis.
One of these conductors has also been coupled to one insulated ring surrounding
the axis and tho other conductor to another insulated ring surrounding the axis
and the current has been led off from the insulated rings by metallic brushes or
rubbers made to bear upon them.
In place of thus leading off the current from the insulated rings we form cach
ring with a disc projecting outwards around it. We surround the outer part of
each disc with a fixed ring which is U shaped in cross section in such manner that
the two sides of the U shaped ring come on either side of the disc but do not
touch it.
These rings stand vertically as the armature axis is horizontal as is usual. The
lower part of the ring we fill with mercury and we may also spread out the mouth
of this lower part of the ring to make it serve as a reservoir or we may lead a pipe
from it to a reservoir in any other convenient position if necessary.
When the axis is revolved the mercury is caused to spread itself uniformly all
around the circumference of the fixed trough ring and form a conductor from all
parts of the circumference of the disc to the ring from which the current is led off
by a suitable conductor.
In the Drawing hereunto annexed we have shewn contact apparatus of the
above kind applied to insulated conductors carried through the hollow axis of a
dynamo machine it may be of any dynamo machine adapted for producing an
alternate electric current.
Figure 1 is a horizontal section, Figure 2 a vertical transverse section and
Figure 3 a side elevation of the axis and contact mechanism,-Figure 4 is a plan
view in section of the terminals of the machine and of a box or casing by which
they are enclosed. Figure 5 is a vertical transverse section of one of the discs and
trough surrounding it.
In these figures A is one end of the hollow axis of the dynamo machine. B is
part of the bearing in which it revolves. Cand D are two concentric insulated
conductors carried through the centre of the axis A. On the end of the conductor C
is secured a disc C' and on the end of the conductor D a disc D'. E E are rings
of a U form in cross section encircling the circumference of the disc. These rings
we make in two halves which have lugs projecting from them. The lugs aro
bolted together by bolts F as shown at Figures 2 and 3. The central part of cach
bolt we form as a cylinder F through which pins G which project from the end of
the bearing B are passed so as to support the Ū shaped rings and hold them rigidly
in place. The tubular portions F of the bolts are insulated from the pins G by
strips of insulating material driven between them and also by insulating washers
interposed between the ends of the tutes F and the nuts H which are screwed on
to the pins G.

page_text: The boss or ring from which each disc C¹ or D' projects is made of greater width
than the disc and a V groove or grooves are formed around the circumference of
these projecting bosses as shewn corresponding grooves being formed in the troughs E.
These grooves tend to prevent any escape of mercury from the trough more
especially at the times when the speed of rotation of the axis is being reduced or
arrested. The lower part of each trough is widened out at its mouth as shewn at
Figure 5 so that when the axis ceases to revolve the mercury which previously
was being distributed all around the circumference of the ring trough may collect
in the enlargement of reservoir so formed-or in place of this the pipe might as
before stated be if preferred led away to a separate reservoir.
I. I. are washers of insulating material interposed between the discs C¹³ D¹. Jis
a metallic distanco piece between the washers. C. D. are nuts screwed on to the
ends of the conductors C'and D. K are conducting bars by which the rings E are
put into electrical communication with insulated terminal blocks L. M, they are
connected to lugs which extend from the cylindrical portion F¹ of one of the
bolts F. OO are funnels from which mercury can be supplied to the troughs E.
These funnels are covered over at the top by caps.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be perforined we declaro that what
we claim is:
(1) In dynamo machines for producing alternating electric currents and in which
the currents set up in the revolving armaturo are led off by two insulated
conductors the combination of a disc secured to each conductor and having its
circumference and outer parts of its sides surrounded by a trough ring containing
mercury or other suitablo conducting liquid substantially as described.
(2) The construction of contact mechanism for conveying away an electric
current from a conductor or conductors carried by the revolving axis of the
armature of a dynamo electric machine substantially as herein before described and
illustrated in the Drawings annexed.
Dated this 10th day of November 1884.