Improvements in and relating to Electric Motors and Dynamo Electric Machines.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in and relating to Electric Motors and Dynamo
Electric Machines.
SIDNEY GEORGE BROWN, 1, St. John's Road, Chelmsford, Essex, Electrical En-
gineer, do hereby declare the nature of this invention to be as follows:-
The invention relates to improvements in the field magnets and exciting coils of
electric motors and dynamo electric machines and has for its object the making
of a compact form of field magnet readily adapted to the construction of what are
termed enclosed types that is a type of machine having all or most of its working
parts enclosed in a metal case mostly of magnetic material and which forms part
of the magnetic circuit.
To accomplish this I construct the field magnet coils in two parts inclining
them at an angle to each other and placing them in such a position that they
completely surround the armature and cross each other at or near the middle
of each of the coils.
Where the two coils seperate at the top and bottom supposing them to cross at
the sides I introduce the magnet poles and connect the two poles by magnetic
material which is carried round outside the coils.
Dated this 1st day of June 1897.
J
:
SIDNEY GEORGE BROWN.
Improvements in and relating to Electric Motors and Dynamo
Electric Machines.
SIDNEY GEORGE BROWN, 1, St. John's Road, Chelmsford, Essex, Electrical En-
gineer, 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 improvements in the field magnets and exciting coils
of electric motors and dynamo electric machines and has for its object the making
of a compact form of field magnet readily adapted to the construction of what is
termed an enclosed type that is a type of machine having all or most of its working
parts enclosed in a metal case mostly of magnetic material and which forms part
of the magnetic circuit.
To accomplish this I construct the field magnet exciting coil in two parts in-
clining them at an angle to each other and placing them in such a position that
077

page_text: they completely surround the armature and cross each other at or near the middle
of each of the coils.
Where the two coils seperate at the top and bottom supposing them to cross
at the sides I introduce the magnetic poles and connect the two poles by mag-
netic material which is carried round outside the coils.
Referring to the accompanying drawings which illustrate my invention.
Figure 1 shows a sectional view of the field magnet constructed according to
my invention.
The armature is shown in position between the magnetic poles M1, M2.
F1 F2 represents the two exciting coils. These completely surround the arma-
ture and are shown at an angle thereto. They cross each other at the sides, this
being shown by the dotted lines which represent the continuation of the coils.
Where the coils F1 F2 separate at the top and bottom, the magnetic poles are
introduced. These poles have their magnetic circuit completed by the outside
case shown in section, which would be constructed of magnetic material.
Figure 2 shows an end view of the magnetic circuit in partial section.
For the sake of clearness the armature has been omitted.
F1 F2 represent. again the field magnet coils which are as shown carried right
round the armature, the magnetic poles M1 M2 being in position between them.
O is a section of the outside case which is of magnetic material.
This as shown connects the magnetic poles M1 M 2 and would be made of suf-
ficient crosssection to carry the needful magnetic flux.
It will be seen from the figure that the magnetic induction has to traverse both
exciting coils and therefore they are in a position to help each other or are additive
in their effect on the magnetic circuit. .
The coils may be wound as a shunt or series winding or one coil may be shunt
and the other a series winding or any other combination may be used.
The outside magnetic circuit could be constructed to any suitable shape.
It could be thinned out as shown in Figure 1 so as to constitute as much as
is necessary of an outside case, if it is for an enclosed type of machine.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
claim is:
-
1 An electric motor or dynamo electric machine having its magnets energised
by two exciting coils, which surround the armature and cross each other at or near
the middle of each of the coils, the magnetic poles being introduced between them,
substantially as and for the purpose specified.
2 An electric motor or dynamo electric machine having a magnetic circuit
and two exciting coils, part of the magnetic circuit being placed between the two
coils in such a manner that their exciting effect is additive.
3 An electric motor or dynamo electric machine having a magnetic circuit
excited by two coils which are inclined at an angle to each other, their exciting
effect being additive, the magnetic poles being placed between them.
4 An electric motor or dynamo electric machine having an armature and field
magnets and exciting coils, constructed substantially as described and illustrated
in the accompanying drawing for the purpose specified.
Dated this 16th day of February 1898.
SIDNEY GEORGE BROWN.