Year: 1887

page_text: I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been com-
municated to me from abroad by Winceslas Camille Rechniewski of 48 Rue de Bondy
Paris in the Republic of France, Engineer, and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
This Invention relating to dynamo electric machines consists in an improved
method of constructing and combining the cores of the electro-magnets and armatures
as hereinafter explained.
It is well known that in the construction of dynamo-electric machines it is very
advantageous to employ electro-magnets having a core of soft iron and especially of soft
iron that has been worked, that is to say, rolled or drawn out to a considerable extent.
According to this invention the elements or plates of the inducing electro-magnets
are or may be stamped or cut out from the same sheets as are employed to make
the core of the armature or induced part which is composed of sheet iron discs or
rings and in constructing the machine these elements or plates of the electro-magnets
are arranged side by side in the same way as the discs or rings forming the core of
the induced part.
By these means electro magnets are obtained presenting a very superior structure.
Moreover the plates or lamina composing the cores can be insulated from one another
in the same way as the discs or rings of the armature or induced part and the
improved electro-magnets can be combined with toothed armatures or armatures
having parts projecting radially (outwards or inwards) at their periphery.
The advantages attending toothed armatures, that is to say, a powerful inducing
or magnetic field with a small expenditure of Electric energy in the field magnets are
thus enabled to be obtained without producing in the pole pieces the Foucault
currents which usually result from the passage of the teeth of the armature before
the said pole pieces.
And in order that the said Invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several

page_text: figures on the annexed sheet of drawings the same letters of reference indicating
corresponding parts in all the figures.
These drawings illustrate by way of example the application of the improved
system of construction to various types of dynamo-electric machines.
Figure 1 of the accompanying drawings represents an elevation partly in section of
a horse shoe magnet combined with a Siemens drum armature provided with
radiating teeth. On referring to the drawing it will be seen that plates or lamina
forming one element or plate for the armature and one for the electro-magnet can be
cut from one rectangular sheet of sheet iron. The electro-magnets are attached to
the bed plate at their bases. a a are two exciting coils and b is the bed plate.
Figure 2 represents an electro-magnet of the same kind combined with a Gramme
ring armature also provided with radial teeth. The electro-magnet is not secured in
the same way as the magnet in Figure 1 being attached to the base plate b by one
of its legs only. In this arrangement only one exciting coil a may be employed.
Figure 3 illustrates a multipolar machine in which the electro-magnets are
arranged internally relatively to the armature the plates or laminæ being placed
directly on the axis.
Figure 4 shows the application of the improved system to the construction of a
dynamo electric machine in which the advantages of great compactness and small
weight are combined. This arrangement of the parts will be readily understood on
referring to the drawing.
Figure 5 illustrates the application of the system to multipolar machines running
at slow speeds.
Having now particularly described and ascertained the nature of this In-
vention and in what manner the same is to be performed I declare that what I
claim is :-
First In the construction of dynamo-electric machines the combination of a
toothed armature with an electro-magnet or magnets having cores formed by plates
or laminæ of sheet iron each plate or lamina being cut out in one or several pieces
the said plates or laminæ being packed together side by side and insulated from one
another in the same way as the plates forming the armature or induced part
substantially as hereinbefore described with reference to the accompanying drawings.
Second The combinations and arrangements of parts constituting improvements
in dynamo-electric machines substantially as hereinbefore described and illustrated in
the accompanying drawings.
1
Namhan 1007