IMPROVEMENTS IN MAGNETO AND DYNAMO-ELECTRIC MACHINES
Year: 1882

page_text: LETTERS PATENT to Lorentz Albert Groth, K.G.V., Civil Engineer and
Proprietor of the Scandinavian Patent Office, under the Firm of L. A. Groth
& Co., 97, Finsbury Pavement, London, E.C., for an Invention of
"IMPROVEMENTS IN MAGNETO AND DYNAMO-ELECTRIC MACHINES." A com-
munication from abroad by Robert Jacob Gülcher Electrical Engineer and
PROVISIONAL SPECIFICATION left by the said Lorentz Albert Groth at
the Office of the Commissioners of Patents on the 5th January 1882.
LORENTZ ALBERT GROTH, K.G.V. Civil Engineer and Proprietor of the
Scandinavian Patent Office under the Firm of L. A. Groth & Co. 97 Finsbury
Pavement London E.C. "IMPROVEMENTS IN MAGNETO AND DYNAMO-ELECTRIC
MACHINES." A communication from abroad by Robert Jacob Gülcher, Electrical
Engineer, and Manufacturer of Biala, near Bielitz, in the Empire of Austria.
These improvements have for object the reduction or obviation of the injurious
heating of the wire coils and thereby the production of an increased useful effect
in the machine.
According to these improvements the inductor rotating between the magnetic
pole surfaces consists of a ring, the core of which is formed of separate magnetically
insulated strips (Lamellen) of soft iron in order to facilitate the change of the
magnetic poles during the rotation of the ring, and thus to reduce the heating of
the ring itself to a minimum. The section of the ring differs materially from those
of other machines, being either of a wedge shape, that is triangular or of a wedge
shaped pointed square or rectangle. This form not only permits of a convenient
and solid fixing of the inductor, but also allows the wire bobbins wound round
such a ring to be exposed to the inducing action of the magnetic pole surfaces from
all sides, and thereby completely obviates the production of heat which in other
machines is formed in the passage of the electric current through the unexcited
wire parts.

page_text: The magnetic pole surfaces are formed in all their parts of a U shaped section
and encloses the rotating ring in such manner that the legs of its cross section
project out on both sides over the wedged shaped points of the section of the ring,
and the latter is thus exposed on all sides to their inducing action.
If it is preferred to give to the ring a complete wedge shape that is a triangular
section, the cross section of the magnetic pole surfaces is also altered accordingly, so
as to take the form of an isoceles triangle with its point cut off in order to fit close
to the triangular shape. In that case however such a wedge-shaped or pointed
wedge shaped section is given to the magnetic pole surfaces that they completely
enclose the section of the ring and thereby act by induction on all parts of the
wire bobbins rotating between them.
Although by the above described peculiar form of the rotating inductor and of
the magnetic pole surfaces enclosing it, one of the most disturbing sources of heat
and one materially prejudicing the useful effect of the dynamo electric machine is
avoided, the heating of the iron core of the rotating ring still remains to be over-
come as the construction of the same out of separate wires or strips (Lamellen)
does not suffice to preventing this heating completely. As besides this the wire
bobbins are wound direct on to the core of the ring they likewise become gradually
heated by the communication of heat from the core of the ring whereby they
oppose a greater resistance to the passing electric currents and thus further
pregudice the effect of the machine.
By a simple mechanical means forming part of the present improvements the
iron core of the ring and the wire spools round it are continually cooled and the
loss of effect above referred to is reduced to a maximum.
The wire bobbins are not wound radially as in other systems, but parallel.
The radial interspaces produced by this method of winding are filled up with
wooden wedges which reach on both sides as far as the outer periphery of the
rotating ring and are fastened with copper rivets to the iron core. These wooden
wedges form at the circumference of the ring with the wire bobbins laying between
them a large number of chambers or paddles (Schaufel) which by the rotation of
the ring between the magnetic pole surfaces enclosing it, continually draws in cold
air froin one side and force it out again warmed at the other thus acting like a
ventilator or fan producing mechanically a strong current of air for the cooling of
the rotating inductor which again allows a greater speed to be given to the rotating
ring.
This ventilator like coiling of the rotating ring may also be so effected that the
above mentioned wooden wedges may be wholly omitted and instead thereof narrow
projections may be arranged at the circumference of the ring between which pro-
jections the wire hobbins may be wound. In this case the wires of the bobbins
themselves forin pallets or paddles at both sides of the ring which produce by their
rotation a strong current of air for cooling the wires.
The construction of the other details of the machine offers no material novelty.
It only remains to remark that in consequence of the great useful effect which may
be obtained by the use of these improvements dynamo electric machines furnished
with them may be used not only for the production of electrical currents for
electric lighting and the clectro deposit of metals, but they are also specially
applicable for the transmission of power to great distances for electric railways and
other such like purposes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Lorentz Albert Groth in the Great Seal Patent Office on the
4th July 1882.
LORENTZ ALBERT GROTH K.G.V. Civil Engineer and Proprietor of the
Scandinavian Patent Office under the Firm of L. A. Groth & Co. 97 Finsbury
Pavement London E.C. "IMPROVEMENTS IN MAGNETO AND DYNAMO-ELECTRIC
MACHINES." A communication from abroad by Robert Jacob Gülcher, Electrical
Engineer and Manufacturer of Biala near Bielitz in the Empire of Austria.
These improvements have for their object the reduction or obviation of the
injurious heating of the wire coils and thereby the production of an increased useful
effect in the machine.
In the Drawings Figure 1 is a transverse section on line A, B, C, D E F of Figure 2
through a magneto or dynamo electric machine constructed with these improve-
ments applied thereto. Figure 2 is a longitudinal section through same on line
G. H. I of Figure 1. Figure 3 is a section on line K. L. of Figure 1 of the inducing
ring and pole surfaces and Figure 4 is a similar section showing a different form of
ring and pole surfaces.
According to these improvements the inductor rotating between the magnetic
pole surfaces consists of a ring M preferably laminated or formed of separate
magnetically insulated plates of soft iron in order to facilitate the change of the
magnetic poles during the rotation of the ring and thus to reduce the heating of
the ring itself to a minimum the section of which ring differs materially from those
of other machines being either of a wedge shape that is triangular as shown in
Figure 4 or rectangular at its outer part and wedge shaped at its inner part as
shown in Figures 2 and 3.
This form not only permits of a convenient and solid fixing of the inductor but
also allows the wires N wound round it to be exposed to the inducing action of the
magnetic pole surfaces O from all sides and thereby completely obviates the produc-
tion of heat which in other machines is produced by the passage of the electric
current through those parts of the wires which are not exposed to the said
action.
The poles O of the inducing magnets have a channel or trough form in transverse
section or a form the section of which is similar to or approximate to that of the
letter U and the sides of the said trough formed poles are of a depth equal to
or greater than that of the rotating ring M plus the coils of wire thereon and the
size internally of the said channel or trough formed poles is only so much greater
than the exterior size of the coils on the ring M as is required to admit of the
said ring rotating freely within the said poles. When a ring of triangular section
is used the sides of the channel or trough formed poles of the inducing magnets
are inclined inwards at the open part of the trough so as to be as close as
practicable to the coils on the sides of the said ring as shown in Figure 4.
By forming the poles and the ring as herein before described all parts of the wire
coils N on the said ring are exposed to the inducing action of the magnets when
the machine is in action.
The arrangement herein before described is also attended by the advantage that
as the ring M rotates air is drawn in between the poles O at one end and driven
out at the other whereby the ring is kept cool which admits of the machine being
driven at a higher speed than would otherwise be practicable.
The improvements as hereinbefore described render the machine to which they
are applied inore useful than ordinary dynamo machines for all the purposes for
which such machines are or may be used.

page_text: Having now described the nature of this Invention and the manner in which the
same is or may be performed or carried into effect I wish it to be understood that
I make no claim to the construction of the induction ring of insulated plates or to
the arrangement of the coils of wire at intervals on the said ring nor do I claim
per se the use of the channel or trough formed poles of the inducing magnets but I
claim as the said Invention of "Improvements in Magneto and Dynamo Electric
Machines"
The combination in such machines of a rotating induction ring wedge shaped or
partially wedge shaped in transverse section (the apex of the wedge being the
inner periphery of the ring) with inducing magnets the poles or polar extensions
of which are of a channel or trough form or of a form in section similar to or
approximating to that of the letter U the depth of the said poles or polar extensions
being equal to or greater than the depth of the said rings plus the depth of the coils
of wire thereon substantially as hereinbefore described and illustrated in the
accompanying Drawings.
In witness whereof I the said Lorentz Albert Groth have hereunto set my
hand and seal this Fourth day of July in the year of our Lord One
thousand eight hundred and eighty two.
LORENTZ ALBERT GROTH. (L.S.)