Improvements in Electric Motors and Dynamo Electric Generators.
Year: 1898

page_text: Date of Application, 7th July, 1898
Complete Specification Left, 7th Apr., 1899-Accepted, 7th July, 1899
PROVISIONAL SPECIFICATION.
Improvements in Electric Motors and Dynamo Electric Generators.
I, FREDERICK HENRY VARLEY, of 82, Newington Green Road, Islington, in the
County of London, N., do hereby declare the nature of this invention to be as
follows:-
Improvements in electric motors especially designed to work with like efficiency
whether driven by direct or alternating electric currents also applicable as a
generator.
According to this invention I employ a multipolar armature consisting of
a series of horse-shoe electro-magnets attached to the driving hub. The winding
of the electro-magnets may be around the poles in small motors and around the
yoke when the diameter of the armature hub is sufficiently large to admit of a
considerable number of electro-magnets being employed. The iron cores of the
armature and field magnets are made of plates of soft permeable iron laid one
upon another to form laminated cores & poles and in order to reduce paramagnetic
resistance especially essential for alternating currents, the section of iron between
the open poles is made as short as possible. The poles of each armature magnet
and the yokes being fixed parellel to the axis and the terminal wires of the
winding of each electro-magnet coil are connected through the commutator
sections to the next coil in series so that a current flowing through the brushes
magnetizes each half of the double pole mutipolar armature in opposite directions.
That is to say the poles on one half of the circumference of the armature are
magnetized alike whilst those on the opposite half are magnetized in the opposite
direction. Viewing the motor from the front end of the axis and dividing it
by an imaginary line drawn say vertically through the centre and calling the
line A, C. The electromagnets between that portion of the circumference included
in the semi-circle A, B, C will be of one direction of polarity whilst the corres-
ponding portion of the circle C, D, A will be reversely magnetized and as each
magnet is double poled the rear portions of the armature will be a reversed
counter-part of the front. In one form of motor the double poled field magnets
have horn-like projections which nearly embrace the circumference of the
armature and in order that the field and armature magnets may readily respond
to the rapid changes in magnetism produced by alternating currents I construct
them of plates of soft permeable iron bent at right angles and placed alternately
upon each other the overlapping portions acting as a yoke and around this the
wire is wound. The number of plates under the influence of the magnetizing
current being double that of each pole ensure a full developement of magnetic
effect whilst the alternate overlapping of the plates at the yoke renders them
capable of more speedily responding to the changes of direction set up by
alternating current excitation. The winding of the wire arround the field and
armature magnets is parellel to the plane of rotation and practically avoids the
generation of extra-current" or "back electro-motive force" such as arises
when drum or ring armatures are employed as the winding of these latter are

page_text: parellel to the axis and cut the lines of magnetic force" at right-angles to
the plane of rotation. The ordinary brush connection with the commutator is
only suitable for one direction of rotation. With a motor and especially when
employed for traction it is necessary to be able to stop or reverse it at any
moment, this I prefer to do by shifting the position of the contacts on the
commutator. These contacts are obtained through a series of tumbler levers
fitted on an axis and working parellel to each other and are drawn by springs
into contact with the commutator sections upon which they bear, uniformly
covering in succession and bearing upon the entire surface of each section.
Though these levers are made to work close against each other the space between
each lever would after a little wear leave ridges on the commutator to avoid
which the contact ends of the levers are made to rest diagonally on the com-
In
mutator sections and act equally well whichever way the motor be driven.
another form of motor in place of the horse-shoe field magnets I employ an
annular field magnet wound circumferentially and acts as a magnetic keeper
to the armature magnets. The armature is attracted on one half of its circum-
ference and repelled on the other. The magnetized annular field surrounds the
armature, but is placed eccentrical and made to touch either at A. or C. The
field may also rotate with the armature. This form of motor I term "single pull'
as attraction is on one side of the axis only. The annular field may be carried
on a seperate axis or supported in a frame by friction rollers which if raised
would touch the armature at C and rotate in one direction or lowered touch at A
and rotate in opposite direction, and when in the intermediate position the field
being concentric with the armature no rotation takes place as the forces are
balanced.
39
In large motors four or more field-magnets may be employed and the motor
may also be used as a dynamo generator.
1
1000
COMPLETE SPECIFICATION.
Improvements in Electric Motors and Dynamɔ Electric Generators.
I, FREDERICK HENRY VARLEY, of 82, Newington Green Road, Islington, in the
County of London, 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;-
My invention relates to improvements in electric motors especially designed to
work with like efficiency whether driven by direct or alternating electric currents
also applicable as a generator. According to this invention I employ a multipolar
armature consisting of a series of double poled or horse-shoe electro-magnets
attached to the driving hub.
The iron cores of the armature & field magnets are made of plates of soft
permeable iron laid one upon another to form laminated cores and poles and in
order to reduce paramagnetic resistance especially essential for alternating
currents the iron in the section of the core between the winding of the insulated
wire and the active poles is made as short as possible as shown in Figs. 1 2 3 4 5
& 6. In which Fig. 1 is a diagramatic representation of the motor showing the
poles N N and SS of the double yoke field magnets with horn-like extensions
embracing nearly each half of the armature or "rotor" and in which yy Y Y
represents the end view of the yokes and wwww the insulated wire around

page_text: 66
"
the same. Fig. 2 shows a side view elevation of field magnets. Fig. 3 perspective
view of the core of the double yoke field-magnet with semicircular or hornlike
extensions built up of plates of soft permeable iron bent at right angles to
form the yokes. In the drawing for the sake of clearness six plates only are
shown as forming the poles and twelve plates in the yokes yy. In practice
however I prefer to use from forty to sixty plates per inch of thickness. Fig. 4
shows a side view of the field magnet, the close proximity of the winding of the
wire around the yoke to the active area of the field being shown by the dotted
lines across the pole horns N. S. Fig. 5 represents in outline the core of a
single yoke field magnet. I prefer however to use the double yoke form for the
purpose of obtaining a more uniform distribution of the magnetism of the field.
Fig. 6 also shows the close proximity of the winding of the field and armature
or rotor" coils to the active poles in which a represents a portion of the
armature & of the field magnets a¹ being an end view section of a core of the
rotor magnets, such magnets being fixed upon the hub parallel to the axis
squirrel-cage form" but leaving no more space between the electromagnets
than necessary for the winding of the coils. The terminal or lead wires of the
winding of each electro-magnet are connected in the usual manner in series at
the commutator sections (not however shown in drawing) so that a current
flowing through the brushes magnetizes each half of the double pole multipolar
armature or rotor in opposite directions shown in Figs. 1, 7, 8 in which
the poles at one end of the "rotor included in the semicircle ABC Fig. 1
are all N whilst those included in C, D, A are S. In some cases especially in
large motors instead of using a single insulated wire for winding the electro-
magnetic sections of the " rotor" I employ two or more wires for each magnet
coil and connect them in series at the commutator sections. That is to say if
twelve electromagnets be employed in the rotor" and the coils wound with
two seperately insulated wires the commutator is provided with twentyfour
sections, if the coils are wound with three wires thirtysix sections, with four
wires forty eight sections are provided in the commutator and so on in pro-
portion to the number of insulated wires employed for each coil winding, the
effect of such multiple winding is to reduce the tendency to sparking at the
brush & commutator connections. Instead of the squirrel cage form of "rotor
I also employ an 'armature" or rotor" built up of iron discs or rings shown
in Fig. 7, & 8 in which Fig. represents an end view and Fig. 8 a longitudinal
section. The disc magnets S N & N¹ S¹ built up say of a hundred plates each
are pierced with winding holes or slots forming tunnels or channels through
which the insulated wire is passed for magnetizing each section. In Fig. 7
only two sections are shown as being wound. The space between SN & NISI
Fig. 8 I fill up with smaller iron discs or rings y, y, to act as yoke plates connect-
ing the magnetic pole sections into horse-shoe magnets arranged parallel to the
axis. The winding of each section being through the tunnels and across tangen-
tially from tunnel to tunnel along the sides of the disc.
"
Fig. 1 is a diagramatic representation the motor showing the field magnets
nearly embracing the circumference of the armature or "rotor." Fig. 3 is a
perspective view of the core of the field magnet showing the arrangement of the
plates of soft permeable iron bent at right-angles placed alternately upon each
other the overlapping portions acting as a yoke and around this the wire is
wound as shown Fig. 4. The number of plates under the influence of the
magnetizing current is double that of each pole as shown by Fig. 3. This
ensures the full developement of magnetic effect whilst the alternate overlapping
of the plates at the yoke renders the fieldmagnet capable of more speedily respond-
ing to the changes of direction set up by alternate current excitation. In place
of a yoke formed by alternate overlapping plates I sometimes build up the 'field
magnets with detachable yoke-cores made of laminated iron plates upon the
ends of which the pole extensions are clamped. The action of the motor is as
follows, for clearness of explanation I shall describe it as working with a

page_text: 35
continuous current. Looking at the motor from the front the upper poles of the
field are NN & the lower SS on the rear side the upper poles are SS & the
lower N N whilst the current flowing around the complete armature magnetizes
it as a whole at right angles to the field a powerful torque is therefor set up and
and maintained in the direction CDA and ABC formed of two attracting
sections A & BC and two repelling sections C, D, A, B when the magnetic
sections in succession pass the point of maximum attractive torque the current
flowing around such section is reversed and the section continues to be moved
forward being driven by the repulsion of the field hence a steady and uniform
torque is maintained. With an alternating current the torque is the same
although the direction of the magnetism in the field and armature coils is always
changing. The efficiency of the motor depends on the ability of the iron cores of
both the armature & field magnets to respond with little loss to the change of
each cycle at a frequency say of 100 per second and also to the direction of the
wire winding of the field & armature magnets being parallel to the plane of
rotation avoids the generation of the extra current or "back electromotive
force such as arises when drum or ring armatures are employed as the winding
of the latter is parallel to the axis and therefor cuts the lines of magnetic force
at right angles to the plane of rotation. With a motor and especially when
employed for traction it is necessary to be able to stop or reverse it at any
moment this I prefer to do by shifting the position of the contacts on the
commutator. That is to say if the + contact be made on the commutator section
connected with the rotor coils at A Fig. 1 and the connection at C the rotor"
will turn in the direction from D to A. If however the contacts are shifted
round an angle of 90° the + connection being at B and the connection
at D the rotor" ceases to rotate the attraction between the field & rotor
magnets being in direct line of pull acts as a powerful brake and when the
contacts are further shifted around the axis to an angle of 180° the + contact
being in connection with the coils at C & the contact at A the "rotor" will
turn in the reverse direction from B to A for this purpose I find that carriers
fitted with adjustable carbon connectors already an article of commerce are very
efficient contact makers and work equally well which ever way the motor be
driven. The " rotor made either of the squirrel cage form or built up of iron
discs or rings already described I also employ with an annular field, shown
diagramatically in Fig. 9 in which the front view of the field presents a complete
ring of N magnetism the rear being S. The horse shoe electro magnets of the
rotor" below the point of approach at C being of like kind of magnetism are
repelled, whilst those above C₁ are attracted the annular field acting as a
magnetized keeper to the horse-shoe magnets of the "rotor" a constant pull is
set up on the upper side of the axis, and likewise a constant push on the lower
side causing the rotor" to turn in the direction from A over to C. The
insulated wire of the annular field winding is connected to two slip-rings and
the exciting current maintained by rubbing contact brushes, not shown in draw-
ing. The field supported by four friction rollers rrrr is allowed to rotate with
the "rotor." Upon the electro-magnets arriving in succession at C the current
flowing through them is reversed at the commutator and each electro magnet of
the "rotor "in succession continues to move forward being repelled. The power
of the motor being derived from the direct pull between the electro-magnets and
the annular keeper above C and by the repulsion below that point. If the
frame F which carries the four friction rollers rrrr be move sideways the
"rotor" will come into close contact at A and then rotate in the opposite
direction from C over to A. If the frame F be moved to the intermediate position
central to the axis of the "rotor" rotation ceases. This form of motion I term
'single pull" as attraction is only on one side of the axis. In large motors
four or more field-magnets may be employed and four or more brushes or carbon
contacts made at the commutator, or batteries of field-magnets employed. Fig. 6
illustrates this in which a double field magnet is employed with a three pole
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66
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page_text: armature magnet, in the same way three field magnets with a four pole armature
or four field magnets with a five pole armature and so on may be employed in
order to maintain the highest paramagnetic conduction by means of a series of
short magnetic circuits.
These motors may also be used as dynamo generators.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is-
1. The special construction of multipolar armatures substantially as and for
the purpose described and shown with reference to Figs. 6, 7, 8.
2. The use of two or more winding wires for the armature or rotor coils to
reduce the tendency of sparking at the commutator substantially as & for the
purpose described.
3. The construction of field magnets with plates of soft permeable iron bent
at right angles placed alternately upon one another to form the yoke-such
yoke having twice the number of plates of each pole substantially as & for the
purpose described.
4. The use of a laminated core or cores for the yoke of field magnets in which
the number of plates is double that of each seperate pole for the purpose of
securing an effective field with alternate current excitation as and for the purpose
described.
5. The use of double pole multipolar armatures and double pole field magnets
which enable the winding to be parallel to the plane of rotation as and for the
purpose described.
6. And generally the invention described for obtaining an effecient motor
capable of being driven either by direct or alternating current.
Dated this 7th day of April 1899.
FREDERICK HENRY VARLEY.