Improvements in Dynamo Electric Machines.
Year: 1890

page_text: Date of Application, 9th July, 189
Complete Specification Left, 11th May, 1891-Accepted, 4th July, 1891
PROVISIONAL SPECIFICATION.
Improvements in Dynamo Electric Machines.
I WILLIAM HARDING SCOTT Electrical Engineer of Gothic Works King
Street Norwich do hereby declare the nature of this invention to be as follows:-
The object of this invention is to minimise the effect of the cross current ampère
turns on the armature of a dynamo electric machine, & so prevent lead & increase
the amount of current that an armature will carry without sparking. This is
accomplished by splitting up as much as possible the pole pieces, & where possible,
the magnets in a direction parallel to the direction of the lines of force due to the
coils on the magnets, but cutting across the direction that would be taken by lines
of force that would be produced by the cross current turns in the armature.
This cutting up of the pole pieces & magnets while it does not effect the flow of
the lines of force due to the magnet coils prevents these lines of force being deflected
& twisted round the pole pieces by the action of the cross current turns.
A convenient way of doing this in a double magnetic circuit machine is to divide
the two circuits across the centre of the pole pieces leaving a considerable space
between the joint except at the face of the pole piece itself, where the iron must
nearly but not quite meet, to preserve practically the continuity of the pole
pieces.
This space between the halves of the pole pieces may be filled up or partly
filled up with non-magnetic metal, & the two halves be held together by bolts or
otherwise.
Where it is not practicable to split the pole pieces as described above we may
cast deep recesses into the centre of the pole pieces leaving webs of metal sufficient
for strength but not sufficient to carry any considerable number of lines of force.
These recesses may go right through ending at the inner surface of the pole piece
in a narrow slot or they may go nearly through & be finished by drilling, sawing, or
a parting tool.
In the case of double magnetic circuit machine, as well as single magnetic circuit
machines we further cut up the pole pieces, & may carry where convenient the
division or slot right into the magnet in some cases cutting the magnet completely
in two, this division or slot must always follow the direction of the lines of force due
to the magnet coils, but be at right angles to the direction that would be taken by
the lines of force due to cross current turns in the armature.
Dated this Eighth dow of July 1890.
WILLIAM HARDING SCOTT.
COMPLETE SPECIFICATION.
Improvements in Dynamo Electric Machines.
I WILLIAM HARDING SCOTT of Gothic Works Norwich in the County of
Norfolk Electrical 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 object of this invention is to minimise the effect of the cross current ampère
turns in the armature of a dynamo electric machine (that is the current in the
armature under the pole pieces) and so prevent lead and increase the amount of
current that an armature will carry without sparking. This is accomplished
according to this invention by splitting cutting or dividing the pole pieces or both
the pole pieces and the magnet cores in a direction parallel to the direction of the

page_text: lines of force due to the coils on the magnet cores, but cutting across the direction
that would be taken by lines of force that would be produced by the cross curren
turns in the armature.
This splitting cutting or dividing of the pole pieces or pole pieces and magne
cores whilst it does not affect the flow of the lines of force due to the magnet coil
prevents these lines of force being deflected and twisted round the pole pieces by
the action of the cross current turns.
A convenient way of doing this in a double magnetic circuit machine i
illustrated by Figure 1 of the accompanying drawings. The two magnetic circuit
are divided across the centre of the pole pieces as at A leaving a considerable
space between except at the face of the pole piece itself where the iron may
nearly but not quite meet as at a³ to preserve practically the continuity of the
pole pieces. The said space may be filled up or partly filled up with non
magnetic metal or material (such for instance as brass) as at and the parts
may be held together by bolts and nuts or in any other convenient way.
Where it is not practicable or desirable to split the pole pieces as herein-
before described I may cast deep recesses into the centre of the pole pieces
leaving webs of metal sufficient for strength but not sufficient to carry any
considerable number of lines of force. These recesses may be cast right through
ending at the inner surface of the pole piece in a narrow slot or they may be
cast nearly through and be finished by a drilling sawing or parting tool. Such an
arrangement is illustrated by Figure 2, where the parts are marked as in Figure 1.
In either double or single magnetic circuit machines I may cut up divide or slot the
pole pieces and carry the cuts divisions or slots right into the magnet cores in some
cases even to the extent of cutting the magnet cores and pole pieces into two or
more parts. The cuts divisions or slots must always follow the direction of the
lines of force due to the magnet coils but be at right angles or across to the
direction that would be taken by the lines of force due to the cross current turns
in the armature.
In Figure 1 I have shewn such cuts divisions or slots at a and in Figure 3 I
have shewn with reference to a single magnetic circuit machine such cuts divisions
or slots a without those shown at A Figure 1.
I have in Figure 3 shewn three such cuts divisions or slots in each pole piece
and core but may use one or more cuts, divisions or slots as desired and they may
extend through the pole pieces alone or through the pole pieces and cores
as shewn.
In Figure 4 I have shewn an arrangement similar to Figure 1 applied to a four
pole machine. In Figure 5 I have shewn the application of the invention to
a multiple pole machine the spaces A being shewn partly filled in with non-magnetic
material b.
In this case the iron is not shewn as nearly meeting at the face of the pole pieces
as at a' in Figures 1, 2 and 4.
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—In dynamo electric machines forming the pole pieces or the pole pieces
and magnet cores with cuts divisions or slots in the direction of or parallel to the
lines of force due to the magnet coils but at right angles to or across the direction
that would be taken by the lines of force due to the cross current turns or current
in the armature substantially as hereinbefore explained with reference to the several
figures of the accompanying drawings.
Second-In dynamo electric machines pole pieces or pole pieces and magnet
cores having cuts divisions or slots in them as at a as and for the purpose
hereinbefore explained with reference to Figures 1, 3 and 4 of the accompanying
drawings.
Third-In double magnetic circuit, or four pole, or multiple pole, dynamo

page_text: machines, magnet-cores and pole pieces divided into parts or halves secured together
with non-magnetic metal or material in the spaces between the halves or parts
substantially as and for the purpose hereinbefore described and shewn respectively
in Figures 1, 2, 4 and 5 of the accompanying drawings.
L
1
ليم
1
1001