AN IMPROVED DYNAMO-ELECTRIC OR ELECTRO-DYNAMIC MACHINE
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Robert William Munro at the Office
of the Commissioners of Patents on the 5th February 1883. Communicated
to him from abroad by Alexcy Evanoff Swonnikoff of Paris, France
ROBERT WILLIAM MUNRO of Kings Cross Road in the County of Middlesex
"AN IMPROVED DYNAMO-ELECTRIC OR ELECTRO-DYNAMIC MACHINE" [Communi-
cated to him from abroad by Alexcy Evanoff Swonnikoff of Paris, France]
This invention relates to a form of dynamo-electric or electro-dynamic machine
whereby simplicity of construction and efficiency of action are obtained.
On an iron base are fixed two iron side frames, from each of which project
towards each other two pairs of field electro-magnets, a pair from the lower part
and a pair from the upper part of each frame. These electro-magnets terminate in
separate segmental pole pieces, the separation of the two pole pieces of each pair
being, not in a radial line, but in a line oblique to the radius or in an undulating
line, so that the parts of the armature in passing it undergo a gradual and not a
sudden change of influence. The wires of these field electro-magnets are so wound
or connected that the pole pieces of each pair will have opposite polarity, the
two N poles being on the one side of the vertical centre line of one frame and the
two S poles being on the other side of that line, so that there is in each case a
N pole diametrically opposite to a S pole. Also the magnets on the one frame
have their poles opposite to those on the other frame which directly face them.
Between these opposing poles revolves the armature which is constructed in the
following manner. On a non-magnetic boss keyed on a central shaft are fixed an
even number, preferably at least 8, electro-magnets each consisting of a central
iron core with two segmental ends, the central core being wound with insulated
wire and the two segmental ends forming polar extensions with flat sides that
revolve between and close to but not touching the polar faces of the field magnets
on each side of them. One of the polar extensions of each armature magnet is
connected by an iron bar across to the other polar extension of the opposite
magnet, the iron bars connecting then being bent to pass clear of the central shaft.
The coils of the armature magnets are connected to plates of a cominutator in the
following manner. Assuming that there are 8 arinature magnets each coiled with
a wire having two ends, then the commutator is made with 8 plates and the one

page_text: end of each coil wire is connected to one of these plates and the other end to the
opposite plate. It is sometimes of advantage to reduce resistance by winding each
of the 8 armature magnets with two separate coils, in which case the commutator
is made with 16 plates. The armature brushes may be mounted on a semicircular
bar which has slotted holes fitting insulated studs projecting from the frame, so
that, by means of a handle, it can be slid in a circular path a little way in either
direction, the brushes which it carries being thus adjusted to the required points of
contact with the surface of the commutator.