Improvements in Electromotors and Dynamos.
Year: 1890

page_text: Date of Application, 26th Mar., 1890
Complete Specification Left, 29th Dec., 1890-Accepted, 7th Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in Electromotors and Dynamos.
I, JOHN VAUGHAN SHERRIN, of 3, Codrington Road, Ramsgate, in the County
of Kent, Electrician, do hereby declare the nature of this invention to be as
follows:-
The field magnet is in solid block form but consisting or built up of very thin
lamine with very thin intermediate insulating layers of or combined with cementing
material. The lamina are stamped out of charcoal sheet iron. I find about
No. 24 Birmingham wire gauge a suitable thickness. The insulating layers may be
formed in various ways, but so as to firmly cement the lamina together.
A suitable mode of constructing the field magnet is as follows:-The lamina
having been stamped out of the thin charcoal iron of the desired form are carefully
enamelled or coated with a non-magnetic material such for instance as copper or tin
and then with a solution of shellac, by brushing over with it or by dipping into it.
Or the aforesaid enamelling or coating with non-magnetic material may be omitted.
The prepared laminæ are then put together say for instance by means of four
through bolts which are gradually tightened up while the field magnet is exposed to
a suitable heat whereby the shellac is made to set and to cement the lamine firmly
together into a solid block. Instead of shellac I may use pitch or other suitable
cementitious insulating material. The shellac or other such material may also be
spread upon paper, flannel, cotton, linen or other more or less absorbent fabric or
material. Sometimes instead of through bolts I use outer bolts which pass through
end dises frames or brackets and serve to unite them to the field magnet and to
compress the lamina into solid block form.
The field magnet may be of any suitable or well known contour or cross section.
Sometimes I make the magnet core pieces as the two opposite parts of a rectangular
frame with the pole piece parts inside embracing the armature. In another form
I make the magnet parts in spreading horse-shoe form and unite the lamina as
described and by a bolt through each leg.
When the invention is applied to dynamos I make every other or every third of
the lamina of tempered steel. I wind the armature wire in one or more layers and
connect the sections to a commutator at one end. Over the first layer I wind one
or more layers and connect the sections to a commutator at the other end. The
wire coils on the field magnet are wound in one or more layers in one length, and
over this I wind one or more layers in another length. This arrangement admits of
using the sets of layers on the armature and the sets of layers on the field magnet
in parallel in a series wound motor. Or I may connect one field magnet coil to one
brush at one end and from the other brush at the same end 1 connect in series to
the other set of layers on the field magnet. The other end of this latter is
connected to one of the brushes on the other commutator and the remaining brush
is connected to the source so also the free end of the first field magnet layer.
The brush holder appliance is on a collar or socket which by means of a set
screw is fixed upon the boss or bearing in which the armature spindle rotates. From
this socket I carry out an arm at each end and upon the outer end of each arm I
swivel the brush holder proper. In order to adjust it to the most suitable angle I
set it by means of an adjusting screw passing through a screw threaded block on
the arm.
Dated this octh d Much 1900
JENSON & SON,
77, Chancery Lane, London, W.C., Patent Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Electromotors and Dynamos.
I, JOHN VAUGHAN SHERRIN, of 3, Codrington Road, Ramsgate, in the County
of Kent, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
The field magnet is in solid block form but consisting or built up of very thin
lamine with very thin intermediate insulating layers of or combined with cementing
material all as hereinafter described.
The lamina are stamped out of charcoal sheet iron of about No. 22 to No. 24
Birmingham wire gauge in thickness and of the desired form. The insulating layers
may be formed in various ways as hereinafter described but so as to firmly cement
the lamina together. I prefer shellac as the insulating and cementing material and
for this purpose I coat the lamina with a solution of shellac by brushing them over
with or by dipping them into it. The so prepared laminae are then put together,
say for instance by four through bolts as shewn in the accompanying drawing where
Fig. 1 is an end view and Fig. 2 a side view of an electromotor constructed
according to this invention. Fig. 3 is plan view of the brush holder.
A. A. A are
the lamina, A' the four bolts which press through them and through the end plates C
and brackets M; these bolts are gradually tightened up while the field magnet is
exposed to a suitable heat whereby the shellac is made to set and to cement the
laminæ firmly together into a solid block.
Instead of shellac I may use pitch or other suitable cementitious insulating
material. The shellac or other such material may also be spread upon paper, flannel,
cotton, linen or other more or less absorbent fabric or material. Sometimes instead
of the through bolts A¹ I use bolts which pass outside the field magnet and through
end discs, frames or brackets and serve to unite them to the field magnet and to
compress its lamina into solid block form. B is the armature of usual form.
The field magnet may be of any suitable or well known contour or cross section.
Sometimes I make the magnet core pieces as the two opposite parts of an outwardly
rectangular frame with the pole piece parts extending inwards embracing the
armature. In another form I make the magnet parts in spreading horse-shoe form
and unite the lamina in the manner described by a bolt through each leg. When
the invention is applied to dynamos I make every other or every third lamina of
tempered steel.
Sometimes especially for electro-locomotives I use a commutator at each end and
wind the armature wire in one or more layers and connect the sections to the
commutator at the one end. Over the said layer or layers I wind one or more
layers and connect the sections to the commutator at the other end. The wire coils
on the field magnet are wound in one or more layers in one length, and over this I
wind one or more layers in another length. This arrangement admits of using the
sets of layers on the armature and the sets of layers on the field magnet in parallel
in a series wound motor. Or I may connect one field magnet coil to one brush at
one end and from the other brush at the same end I connect in series the other set
of layers on the field magnet. The other end of this latter is connected to one of
the brushes on the other commutator and the remaining brush is connected to the
source, so also the free end of the first field magnet layer.
The commutator D here shown is constructed according to Patent Specification
No. 13,473 of 1888, viz., made of a number of gun metal sector pieces corresponding
in number to the number of coils on the armature and with intermediate mica layers
coated with shellac, the whole held together between a central sleeve E and a nut
so as to form a solid block and fixed on the spindle but insulated therefrom. The
brushes G consist of springy copper lamine which act upon the face of the com-
mutator. The brushes are by set screws G' fixed in a socket H which is mounted
on a pillar I so as to be capable of swivelling thereon. The brush holder appliance

page_text: is on a collar or socket L which by means of a set screw L' is fixed on the boss or
bearing M in which the armature spindle rotates. From this socket LI carry out
an arm K at each end with intervening blocks L² of insulating material and upon
the outer end of each arm K I swivel the brush holder proper H on a pivot I as
stated. In order to adjust it to the most suitable angle I set it by means of an
adjusting screw K passing through a screw threaded block K' on the arm K and
pressing with its end on the brush G.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
First. The improved construction of field magnet consisting of thin charcoal iron
lamine cemented together with insulating material and united into a solid block in
the manner described.
Second. The improved construction of adjustable commutator brush holder shewn
on the drawing.
Dated this 29th dar
1000
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.