IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Charles Lever at the Office
of the Commissioners of Patents on the 6th March 1883.
L
CHARLES LEVER of Bowdon in the County of Cheshire "IMPROVEMENTS IN
DYNAMO ELECTRIC MACHINES
"
This invention has for its object improvements in dynamo electric machines or
machines which convert mechanical energy into electric currents.
In all dynamo machines which have hitherto been constructed, whether used as
a generator or as a motor either the field magnets or armature have been made to
revolve consequently such machines have of necessity been provided with a
commutator or collector.
The first part of my invention relates to a method of obviating the use of the
commutator, and its essential feature consists in keeping both the field magnets
and the armature fixed. Instead of revolving the armature or the field magnets
I pass through one or both poles of the field magnet or magnets, a rod of
magnetisable or paramagnetic metal, preferably iron or steel and which can
revolve freely through the said field magnet pole or poles. Attached to this iron
or steel rod or forged thereon is a plate, cylinder or ring of iron which can revolve
with the said rod and which becomes polarised or magnetised from the pole piece
of the field magnet. The rod or bar of iron or steel which passes through the pole
of the field magnet carries a pulley at the end opposite to the said plate cylinder
or ring of iron so that when the pulley is turned the whole revolve together and
therefore when the field magnet is energised the said plate cylinder or ring of iron
or steel will be polarised or magnetised as it revolves. I shall call this plate
cylinder or ring of iron, the inductor to distinguish it from those parts which
have hitherto been called the armature and field magnets. When a ring or drum
armature is employed the inductor is preferably made into a ring or cylinder which
completely covers the insulated wire wound upon the said armature so that when
the said inductor rotates induced currents are set up in the armature coils. If a

page_text: pole armature be employed then the inductor would preferably be made in the
form of a plate so as to rotate before the coils or electro magnets on the armature.
In order to increase the inductive effect of the field magnets on the armature coils
I fix the said coils on a projection of iron or steel attached to the opposite pole
piece of the field magnet or magnets to that through which the inductor revolves
so that while the fixed piece of iron or steel on which the armature coils are
arranged is magnetised with one polarity the revolving inductor is magnetised
with the opposite polarity. The inductor whilst revolving is made to come as
close as possible to the armature or induced coils without touching the same
In constructing a dynamo on this principle with a ring or drum armature the
said armature can be fixed in two ways viz: either the cylindrical inductor can be
made to revolve whilst the armature is fixed on the polarised and rigid projection
or it can be fixed to the said cylindrical piece of iron or steel which in this case
must be rigidly attached to its pole piece and the inductor which revolves can be
made to rotate inside the ring or drum armature.
· In order to facilitate the cooling of the armature coils which will be enclosed
between the revolving inductor and the rigid polarised projection; the said inductor
and projection can be perforated or provided with longitudinal slots. The object
then of this part of my invention consists in keeping the field magnet coils and
the armature coils fixed and providing polarised revolving rings, plates or cylinders
of paramagnetic metal which rotate before said armature coils whereby the necessity
of a commutator is avoided.
The second part of this invention relates to a method of arranging the coils of
wire both on the armature and field magnets so that a dynamo machine con-
structed according to the first part of my-invention can be made either to give
alternate or direct currents of high tension, or low tension and also so that the
machine can be arranged either as a shunt series or separately excited dynamo.
Since as already stated both the armature or induced coils are fixed this consists
simply in bringing the coils both of the armature and of the field magnet or
magnets onto a suitables witch board, the armature and field magnet coils being
of course divided into as many sections as desired.
If the dynamo is required to generate continuous or direct currents of high
tension or electro motive force and be arranged as a series dynamo then the whole
of the coils will be connected on the switch board in series or if it be desired to
arrange the machine as a shunt dynamo then the field magnet coils can be coupled
in derivation to the external circuit
Again if the dynamo is required to generate continuous or direct currents of low
tension the coils must be connected on the switch board in multiple arc. Some
of the armature coils can also be connected so as to allow the current to only pass
through the field magnets and thus separately excite the dynamo.
Que half of the switches on the said switch board must be made reversible so
that when the machine is required to generate alternate currents one half of the
coils on the armature are connected with these reversible switches and the currents
thus diverted in opposite directions through the external circuit. The field
magnets in this latter case can be excited from any even number of coils on the
armature.
This second part therefore of my invention consists in making a dynamo machine
which can be used to work electric arc lamps, electric candles and incandescent
lamps and also for charging accumulators. The field magnets may either be
permanent or electro magnets preferably the latter.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Lever in the Great Seal Patent Office on the 6th September
1883.
CHARLES LEVER of Bowdon in the County of Cheshire
DYNAMO ELECTRIC MACHINES
">
"IMPROVEMENTS IN
This Invention has for its object, improvements in dynamo electric machines or
machines which convert mechanical energy into electric currents.
In dynamo machines as hitherto constructed when used as generators either the
field magnets or armature have been made to revolve, consequently such machines
have of necessity been provided with a commutator or collector.
My Invention relates to a method of obviating the use of the commutator
or collector, when the field magnets of the dynamo are separately excited
and its essential feature consists in keeping both the field magnets and the
armature fixed. Instead of revolving the armature or the fieldmagnets, I pass
through one or both poles of the field magnet or magnets, a rod of magnetizable or
paramagnetic metal, preferably iron or steel and which can revolve freely through
the said field magnet pole or poles Attached to this iron or steel rod or forged
thereon is a plate or cylinder of iron as hereinafter described which can revolve
with the said rod, and which becomes polarized or magnetised from the pole piece
or pole pieces. of the field magnet. The rod or bar of iron or steel which passes
through the pole or poles of the field magnet carries a pulley at one or both ends
of the said plate or cylinder of iron, so that when the pulley is turned the whole
revolve together, and therefore when the field magnet is energised the said plate
or cylinder of iron or steel will be polarized or magnetized as it revolves. I shall
call this plate or cylinder of iron, the inductor to distinguish it from those parts
which have hitherto been called the armature and field magnets When a ring or
drum armature is employed the inductor is preferably made in the form of a
cylinder as hereinafter described which covers the insulated wire wound upon
the said armature coils so that when the said inductor rotates induced currents are
set up in the armature coils. If a pole armature be employed then the inductor
would preferably be made in the form of a plate as hereinafter described so as to
rotate before the coils on the armature. The inductor whilst revolving is made to
come as close as possible to the armature or induced coils without touching the
same.
The said inductor is provided with longitudinal slots forming intermediate ribs
or arms the number of which is preferably half of that of the armature coils or
induced coils, by this means I also facilitate the cooling of the armature coils.
The object then of my invention consists in keeping the field magnet and the
armature coils fixed and providing polarised revolving inductors of paramagnetic
metal which rotate before said armature coils whereby the necessity of a com-
mutator or collector is avoided. The field magnets of the dynamo must be
separately excited and the currents generated will be alternating.
Figure 1 of the accompanying drawings is a perspective view of my cylindrical
inductor as applied to a ring or drum armature. A is the rod or spindle of para-
magnetic metal such as iron or steel which passes through the pole piece of the
field magnet and which is made to revolve by strap and pulley. Attached to this
spindle A or forged thereon is a cylinder B provided with longitudinal slots

page_text: forming intermediate ribs or arms 6 the number of which is preferably half that
of the armature or induced coils which latter are here (contrary to the usual
practice) shown wound upon a cylinder D of diamagnetic metal such as brass. This
cylinder D is made hollow for the purpose of mounting it on the wooden block E
which is secured to the base plate of the machine by means of the bracket or
support F. The inductor B whilst revolving is made to come as close as possible
to the armature or induced coils C without touching the same.
Figure 2 is a perspective view of another arrangement in which the inductor B
with ribs b revolves inside the armature coils C which latter are fixed inside the
rings of the casting G preferably of diamagnetic metal secured to the base plate of
the machine.
Figure 3 is a front elevation of a dynamo machine complete with the inductor
described with reference to Figure 2. The shaft A A passes through the poles H
of the field magnet which is separately excited, the current being made to traverse
the coils so as to polarize the two poles H with the same polarity. The armature
coils C can be coupled or connected in series in multiple arc or in separate circuits
by suitably arranging and insulating the terminals on the casting G but in
we number, the coils with con-
all cases they must be so connected that if
secutive numbers 1, 3, 5, 7 and so on these are wound in one direction and the
other alternate coils 2, 4. 6. 8, and so on are wound in the opposite direction.
The exciting bobbin or armature may be mounted on the top of the machine as a
unipolar dynamo its field magnet being a projection on the yoke S, as also shown
in Figure 4.
Figure 4 is a front elevation of a complete machine constructed according to my
invention when a plate inductor is applied, Figure 5 is a side elevation and
Figure 6 a vertical central cross section.
B is the plate inductor which is formed with slots and radial arms b as best
shown in Figure 6. C are the coils which are wound alternately right and left as
in the inductor Figures 1, 2 and 3. The inductor B is mounted magnetically on
a spindle A which is of iron or steel and passes through the pole pieces of the
field magnet H H. The coils of the field magnet are so wound that the two poles
through which the spindle A revolves are of the same polarity when the current
from the exciter K is passed through them; if these poles are north as shown
at N N then the South poles will be at S S as shown. The coils C are fixed on
the frames D in the ordinary manner, and these frames D are secured to the bed-
plate and to the yoke above. The bearings L L are mounted on the latter and
carry the spindle for the exciting bobbin K, the yoke acting as field magnet for
the bobbin K, the whole thus acting as a unipolar dynamo. The bobbin K is
covered by a cap M of diamagnetic metal. The exciter K is driven by straps
from the pulleys P, so that if one strap should slip or break the machine may still
'run with the other strap. The coils C may if desired be wound so as to cover more
of the ends or faces of the ribs or arms b, or another set of coils may be wound
on a ring frame surrounding the periphery of the inductor thus also utilizing the
ends of the arms b. The coils Care wound on brass spools which are mounted on
The currents are collected
the frames D in any ordinary and well known manner.
by passing the wires from each coil to binding screws which are mounted on and
insulated from the periphery of the frames D. The circuits from the binding
screws are connected in multiple arc or otherwise as required. When permanent
magnets are employed the exciter K is dispensed with.
Having thus described the nature of this invention and the mode of carrying
the same into effect I declare that I claim :—
In a dynamo electric machine in which the field magnets and armature or
induced coils are fixed the application of a polarized revolving inductor
magnetically connected to its paramagnetic spindle which revolves in one or more
pole pieces of the field magnet, the said inductor rotating before between or

page_text: within the said armature or induced coils whereby alternate electric currents are
generated and distributed without the usual collector substantially as described
and also as illustrated in the accompanying drawings.
In witness whereof I the said Charles Lever have hereunto set my hand
and seal this First day of September in the year of our Lord One thousand eight
hundred and eighty three.
CHARLES LEYER (L.S.)