Improvements in Dynamo Electric Machines.
Year: 1894

page_text: Date of Application, 21st Feb., 1894-Accepted, 7th Apr., 1894
COMPLETE SPECIFICATION.
Improvements in Dynamo Electric Machines.
I, ERNEST ALEXANDER CLAREMONT, of Cooke Street, Hulme, Manchester,
in the County of Lancaster, Electrician, 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 :-
--
This invention relates to dynamo electric machines, and the objects of this
invention are to secure perfect magnetic contact of the field magnet limbs with the
cast metal pole pieces, and to obtain increased magnetic effect on the armatures of
machines as aforesaid.
I effect these objects by the means hereinafter described and as shown in the
accompanying sheet of drawings, in which
Fig. 1 represents the front view of a yoke with two field magnet limbs attached
and with pole pieces fitted thereon:
Fig. 2 is an inner side view of a pole piece constructed according to my
invention, and
Fig. 3 is a transverse section of armature.
In these views similar letters refer to similar parts.
In pole pieces such as are ordinarily employed, the hole that is formed therein
for the reception of the upper portion of the metal limb, is of a size that is required
to fit on said metal limb, but is incapable of adjustment, so that if slack it must
remain slack, or if the internal diameter is slightly bare, said pole piece must be
either forced on with risk of fracture, or superseded by one of the exact size.
In this invention I construct pole pieces such as a with divisions as b, and
slightly less in the bore than the turned upper portion of the limb e on which said
pole piece is intended to be fitted. By the split form of construction of the pole
piece, a limited amount of elasticity is obtained, permitting of contraction or
expansion to a small extent.
In order to place the pole piece a on the limb e, said pole piece is forced slightly
open and slipped on so as to rest on the shoulder e¹, said pole piece will when
released, contract, and thereby grip the limb e.
Increased effectiveness is obtained by means of the set screws d and d¹, which
ensure complete contact of the pole piece with the limb.
In order to obtain an increased magnetic effect on the armatures of dynamo
electric machines without seriously disturbing the lines of force passing through
them during rotation, I construct an armature by a combination of a greater or
less number of wires, placed in grooves formed on the periphery of the disc g,
and wires placed around the periphery or edge of said disc as represented in
Fig. 3.
Having now particularly described and ascertained the nature of this my said
invention, and in what manner the same is to be performed, I declare that what I
claim is
1st. In the construction of dynamo electric machines, the use of pole pieces
that are formed with divisions as b, in the manner and for the purpose substantially
as hereinbefore described.
2nd. In dynamo electric machines the construction of the armature by means of
a combination of wires laid in grooves formed in the periphery of the disc, and

page_text: wires laid on the periphery of said disc, in the manner and for the purpose
substantially as herein before described.
Dated this 20th day of February 1894.
THOMAS PRESCOTT,
53, Arcade Chambers, St. Mary's Gate, Manchester,
Agent for the Applicant.