Improvements in Electro-magnetic Motors.
Year: 1890

page_text: Date of Application, 13th Feb., 1890
Complete Specification Left, 13th Nov., 1890-Accepted, 7th Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in Electro-magnetic Motors.
I, GEORGE RICHARD POSTLETHWAITE, of 124 Park Road, Aston-juxta -
Birmingham, Mechanical Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to improvements in the form and also the construction of
electro magnets and the entirely new or novel way of arranging such magnets for
the purpose of obtaining a much greater increase of motive power from a given
current of electricity than has hitherto been accomplished.
In electro-motors hitherto introduced for actual work, they consist chiefly of but
one or two lines of attraction and even where the force of repulsion is utilised in
motors that are so constructed, the combined effects are but extremely small
Therefore the object
compared with what may be obtained by this, my invention.
of my invention is to so form and arrange such magnets as to increase the effect
without in any way increasing the cost for electric current required to work the
same, and thereby cheapen the usefulness of such motors for ordinary use or
purposes.
The principles of my invention consist of forming such a circuit or magnetic field,
of any unlimited number of such magnets, so that any relative number of such
magnets, can be made to operate upon a revolving armature, made up with an
equal number of bars, so that each such magnet attracts each of such armature bars
simultaneously, and so successively as to equal one continuous field of attraction of
a most powerful nature throughout its entire revolution and without any release or
dead point.
In explaining the principles of my invention, I will first proceed to describe the
manner in which I construct my magnets, commonly called field magnets:-
These magnets which are entirely novel in shape or design, and which are much
more powerful from a given amount of wire in their manufacture than those of any
other shape, consist of two poles. Each pole is in the shape of a web or blade,
each web or blade projects at right angles to, but in a direct line with one common
base or yoke. The length of the webs or blades may vary proportionately to any
extent, but I prefer them to be extremely thin as compared to their length; so that
I obtain a much wider field of attraction by the extra length of such blades, and
being thin, I get a greater number of magnets in a given space, consequently more
lines of attraction, or a greater number of pulls. Each blade is made about one third
thicker at its base or union with the yoke than at its face, or that part forming the
surface of attraction. And each magnet may be cast complete in malleable iron, or
made up in parts from good wrought iron. They are lapped with insulated copper
wire, and one of the ends from each coil is joined up in the usual manner, to form
the continuity of the wire round both webs thus forming one complete magnet.
The other two terminal wires from such a magnet, I name as north and south.
The south wire meaning the end by which the current enters the coils for traversing
round the magnet, and the north wire, the end the current leaves by.
I arrange any desirable number of such magnets as just described, to form a
circle, as closely packed as possible; the yoke of each magnet at each of their ends
are made to project about 1 inch longer than what is necessary to form the magnet,
and each such end is secured to a circular metal casting or perforated disc and thus
I form the body of the motor, and with the end castings perforated sufficiently
large enough to take in the armature; so that with the yokes of the magnets
outwards and their attractive faces inwards, and each directed centrally, they are
now ready for joining up, but whatever number may be chosen to form such a
circle, or magnetic field, that number must be divisible by three, as for instance, to
CO

page_text: form a two pull motor, 6 such magnets are required, and to form a three, pul
motor, 9 magnets are required, or a thirty pull motor, 90 such magnets would be
required, and so whatever number of magnets may constitute the circle or field
they are divided into three distinct series, each quite independent of the other. I
then construct an armature capable of revolving round its own axis, and consisting
of as many horizontal bars placed at equal distances around its circumference as
there are magnets in each series, so that we now have three magnets to each
armature bar, so that when the armature is in its position and surrounded by the
circle of magnets, and each bar, if placed face to face, with as many magnets, there
are two spare magnets between each two armature bars; now the magnets which
face each bar of the armature, cannot help but be those which constitute one
complete series out of the three, and the next series would consist of those
immediately before each of the armature bars in a forward direction, and the third
and last series would consist of those immediately behind each bar of the armature,
so that while matters rest in this position, if the current be supplied, the contact at
the commutator is such that every magnet in front of cach armature bar becomes
immediately magnetised, and every magnet behind each bar being neutral, a
forward motion of the armature is imperative, not by the impulse of a single
magnet upon a single armature bar, but by the united efforts of the whole series of
magnets upon the whole of the bars surrounding the armature simultaneously.
Then as soon as this series of magnets has done its work, the armature bars are not
left to travel any atom of space alone, before they are immediately acted upon by
the next forward series of magnets, so that each series of magnets are always
magnetised in advance of the armature bars so long as the current is supplied so
that by the adoption of my new system of magnets arranged in three seperate
series, all the difficulties and impossibilities of obtaining motion from more than a
small number of magnets in a circle is entirely overcome, for upon any other
system, the magnets forming the circle or magnetic field must necessarily be placed
far apart so to prevent counter attraction in a backward direction, or neutral effects,
and therefor a considerable portion of the revolution of the armature has to be
performed while the actuating current is allowed to remain idle, hence the weakness
of motors so constructed, but upon my system, the magnets are purposely made to
occupy much less space so as to get them as close together as possible in the
formation of a circle, so close in fact, that the marginal lines of attraction may
overlap each other, so that when one series has done its work, the next in advance
immediately operates upon the armature bars without loss of time or space, so that
the whole circle of attraction may be said to be continuous and with the additional
advantage that each series may consist of any number of magnets, all of which act
simultaneously upon every bar surrounding the armature, so that the power
obtainable by such means may be said to be unlimited. It may be admitted that
the time required in the demagnetisation of the magnets has a retarding effect upon
the armature, and therefor a certain amount of loss must result, but this only
occurs at very high speeds, as when running unloaded, or a good portion of the
work suddenly thrown off, which in either case is favourable in preventing what may
be termed racing, and the same effects go to prove that the slower the speed, the
greater the power, so that in any case it becomes a desirable advantage, in the
sense of a self-governing motor, for it prevents the tendancy to racing or
unnecessary high speeds when unloaded, and acts with its greatest force when
started under a full load and will soon therefore attain its maximum speed.
In describing the way in which the wires to and from each magnet which forms
the circuit or magnetic field, it will be remembered that I termed the wires of each
magnet as north and south; the south wires being those by which the current enters
the coil surrounding each magnet, and the north wire the one by which the current
leaves the coils, and now by numbering each magnet forming such a circle, say for
the construction of an eight pull motor, from 1 to 24 consecutively, the method of
joining up will be readily understood. It is desirable to begin with the first
magnets nearest the positive or south binding screw, and to this I join the south

page_text: wires of the magnets, Nos. 1, 2, and 3, as one terminal. Then I join the north
wire of number I to the south of No. 4, and the north of this to the south of No. 7,
and so on to magnet No. 22, leaving the north end of this for after considerations.
Now I join the north wire of No. 2 magnet to the south of No. 5, and the north
of this to the south of No. 8, and so on to No. 23 magnet, the north of which is left
as before. Then I join the north wire of No. 3 magnet to the south of No. 6 and
the north of this to the south of No. 9 and so on to No. 24 magnet, leaving the
north wire as before, so that the first series of magnets consists of Nos. 1, 4, 7, 10,
13, 16, 19, and 22, and the second series of Nos. 2, 5, 8, 11, 14, 17, 20, and 23, and
the third series of Nos. 3, 6, 9, 12, 15, 18, 21, and 24 magnets.
The commutator, which is for the purpose of closing the circuit of each
respective series in turn, may be made of any hard wood, or other non-conducting
material, is mounted upon a gun metal bush, and this bush is made to fit upon one
end of the armature shaft or spindle, and sufficiently free as to rotate thereon, and
upon the outer circumference of the commutator 4 metal strips are fixed at equal
distances apart, each strip is also joined to a metallic facing or flange, attached to
the bush and body of the commutator, the 4 metal strips being thus secured to the
commutator. There are 3 contact pieces attached to, but insulated from the body
of the motor and to the first of these contact pieces, is joined the remaining wire
from the magnet No. 22, forming the end of the first series, and the remaining wire
from No. 23 magnet is joined to the second contact piece, and the remaining
wire from No. 24 magnet is joined to the third contact piece, and the terminal ends
of each contact piece, are made to press upon the face or periphery of the
commutator, at equal and certain distances apart. The width or space between
each of the four strips is such, that as one strip is just leaving the third contact
piece, the next strip is in connection with the first contact piece, and before this
strip leaves the first contact piece, it is in connection with the second contact piece,
and before it leaves the second, it is in connection with the third, and before it
leaves the third, the next strip is in connection with the first contact piece, so that
the circuit is never broken, but always flowing out of one series of magnets into
the other, so that one continuous field of attraction is maintained, and the position
of the 4 strips upon the armature, taken in relation to the armature bars, is such
that the current always takes the lead of the said bars, so that the said bars are
bound to follow the current.
The bush upon which the commutator is mounted, is made to fit freely upon the
armature shaft or spindle for the purpose of reversing the action of the motor,
when required, which is accomplished as follows:-In the body of the said com-
mutator, a slot is formed in a diametral line in relation to its position. A stud pin
is made to fit freely into this slot, and one of its ends is secured to the end of the
armature. Then the length of the slot should include the thickness of this stop pin,
and just sufficient space as to allow a partial rotation of the commutator upon the
axis of the armature, so as to give the lead of the 4 strips to the other side of the
armature bars, or from one side to the other, the commutator being held in either
position by means of a fork lever and pin clutch, so that by this means, the action
of a motor so constructed, may be reversed while going at any speed and by the
same means, may be made to act as a powerful and efficient brake when required.
A further advantage which may be obtained from the principles of my invention,
as herein described and set forth is, that by the same, or slightly varied means, any
other form of motion besides that of a rotary one, can be very readily accomplished,
either reciprocating, as that of the piston of a steam engine, or alternating, or for
the actuating of forging hammers, drop hammers, or stamps.
Dated this 12th day of February 1890.

page_text: COMPETE SPECIFICATION.
Improvements in Electro-magnetic Motors.
I, GEORGE RICHARD POSTLETHWAITE, of 124, Park Road, Aston, near the
City of Birmingham, 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:-
This invention relates to improvements in the construction of electro-magnetic
motors, and in the component parts of them, including the electro or field magnets
employed, which are so constructed and arranged, that increased motive power is
obtained from a given current of electricity.
The magnets of ordinary electro-motors, have but one or two lines of attraction,
and even when the combined efforts of both attraction and repulsion are utilized, the
result is small, when compared with the power obtained in my motor, as hereinafter
described.
The essential features of my invention, consists in forming the magnetic field, of
an unlimited number of web cored electro-magnets, in manner, that any relative
number of them, is made to act successively upon a like number of arms of a
revolving armature, made fast upon the driven shaft which carries the armature.
By such an arrangement, a continuous, or an almost continuous field of attraction
of a most powerful character, is attained, during the revolution of the shaft, which
is without dead points.
The motor consists of upright end framings, supported upon a base or feet, and
provided with a longitudinally directed stay.
The end framings are provided with bearings, wherethrough and whereby, the
shaft is supported.
The field magnets, which consist of two web or blade shaped poles, disposed in
the same plane, and united at their outer or base ends, by a yoke or connection bar,
are disposed radially between, and are supported by, the said framings.
The middle part of the shaft as aforesaid, carries a longitudinally directed bar
armature, whilst one end carries a pulley, and the other end has a commutator, with
reversing clutch arranged with it.
The commutator, which is for the purpose of closing the current, has in connection
with it, roller contact slides.
Figure 1 of the accompanying drawings, represents a transverse vertical section
of a four-pull electro-motor, constructed and arranged according to my said inven-
tion, and which said view shows the arrangement of the field magnets with respect
to the unmagnetized revolving armature, which has radiating longitudinally
directed bars.
Figure 2 represents an end elevation of the motor, showing the commutator and
the contact slides, with rollers at their inner ends, for making and interrupting the
current at predetermined positions.
Figure 3 represents the said motor, partly in side elevation, and partly in longi-
tudinal vertical section. This view represents the configuration of the soft iron
cores of the electro or field magnets, which are formed web like, and the north to
the south pole, united by a yoke or cross bar. This view also shows the disposition
of the armature, and the bars of it, and also the position of the commutator, and
the accessory parts of it, whereby the circuit of the current is made or
interrupted.
a is the framing of the motor, consisting of end uprights a², and provided at their
middles, with bearings at, wherethrough and whereby the armature shaft b, is
supported, whose left-hand end is provided with a pulley 62, and the right-hand end
with a clutch 63, and operating lever b, having a stud 6, upon it, which takes
within the groove ', of the said clutch end, whose inner face, has studs, which
are adapted to engage with a metallic facing c², of the commutator c, as hereinafter
described.

page_text: The shaft b, has made fast upon it, an armature d, with longitudinally directed
bars d', directed parallel with, and a little beyond the field magnets e, each of which
consist of two web or blade shaped soft iron plates e², e³, disposed in the same plane,
and united at their base ends by a yoke e, with extensions e', which rest upon the
metallic part of the framing.
These magnets taper from their base or outer ends, to their inner ends, and are
disposed in the direction of radii, and with their extreme inner ends, presented to
the bars of the armature.
Thus, each blade is made about one third thicker at its base or junction with the
yoke, than at its front edge, or that part forming the surface of attraction.
By the employment of thin webs or blades, I obtain a much wider, and extensive
field of attraction, consequent upon the length thereof; and further, by the said
magnets being greater in length than breadth, a greater number can be employed
in a given space, and further, the lines of attraction are consequently more numerous,
and an increased number of pulls, thereby obtained.
The cores of the magnets as aforesaid, may be cast complete in malleable soft
iron, or made up in parts of good wrought iron, and which webbed-shaped cores,
are wound or wrapped with insulated copper wire e, with one of the ends from each
coil, joined up in the usual manner, to form the continuity of the wire around both
webs, thus forming a complete magnet.
The terminal wires of the magnets, designated north and south, the latter
signifying that part, by which the current enters the coils, for traversing around the
cores, and the former, the wire the current leaves by.
The said electro-magnets, are arranged as aforesaid, in the direction of radii, and
as closely packed as possible, and whatever number is employed, or arranged to
form the magnetic field, that number must be dividable by three, as for example in
a four pull motor, twelve magnets as represented, are necessary, so that whatever
number of magnets are arranged to constitute the circle or field, they are divided
into three distinct series, and independent of each other.
The armature, which is marked d, has as many bars d², as there are magnets in
each series, so that there are three magnets to each armature bar, and when the
said armature is in position, and encircled by the magnets, whose acting ends are
presented to the bars, two spare magnets are left disposed between each of the said
bars. Now the magnets, which face each bar of the armature, cannot help but be
those which constitute one complete series, out of the three series.
The next series in order, would consist of those immediately before each of the
armature bars in a forward direction, and the third and last series, would consist of
those immediately behind each bar of the armature as aforesaid; so that if the
current be supplied, the contact of the commutator is such, that every magnet in
front of each armature bar, becomes immediately magnetised, and every magnet
behind each bar, remaining neutral, a forward motion of the armature is imperative,
created not by the impulse of a single magnet, upon a single armature bar, but
by the united attractions or efforts, of the whole series of magnets upon the
entire bars.
Thus, as soon as the first series of magnets has done its work, the armature bars
are acted upon by the next series, and so on, so that each series of magnets, are
always magnetized in advance of the armature bars, that is, during the time the
current is supplied.
By employing magnets arranged in three separate series, a great advantage
accrues, for upon any ordinary system, the magnets forming the magnetic field; must
necessarily be placed far apart, in order to prevent counter attraction rearwardly;
and further, in ordinary electro-motors, the current is allowed to remain idle, hence
a disadvantage in them.
The negative wire connecting the north pole, is marked f, and is passed to the
armature slide 9, which works within guides 92, and has a contact roller g³, at its
lower end, and is kept constantly upon the periphery of the commutator, by a
spring gt.

page_text: u is the collector.
23
The north and south poles, are connected by wires h, while the serial connection
of the magnets, is made by wires i, ², ³, i, j, j³, j, k, k², k³, k, and the connection
of the series in threes, is made by wires 1, m; that is to say, No. 1 magnet is
connected to No. 4, by the wire i, and No. 4 magnet to No. 7 magnet, by the
wire, and the No. 7 magnet, to the No. 10 magnet, by the wire, and the
No. 10 magnet to the No. 1 magnet again, by the wire . The second and third
series, are connected in the same manner as indicated,.while the primary magnets
of each series, are connected together by wires / and m.
From this it will be seen, that the attraction of the said field magnets, is
continuous, and acts simultaneously upon the bars of the armature as aforesaid, so
that the power obtainable by such an arrangement, is most considerable and almost
unlimited.
Further it may be admitted that the time required in the demagnetization of the
magnets, after attraction, has a retarding effect upon the armature, and therefore a
certain amount of loss, but this only occurs at very high speeds, and is therefore
favourable in preventing racing, which goes to prove that by my arrangement, a
slow speed is most favourable for obtaining the greatest power possible.
By this it will be seen, that the motor becomes self-governing, as the same may
act with the greatest force when started under a full load, before it acquires its
maximum speed.
As a further illustration of connecting the magnets one with another, in reference
to their polarity, that is to say, the way in which the wires to and from each
magnet, which forms the circuit of the magnetic field, are arranged as follows:-
The south wires being those by which the current enters the coils surrounding each
magnet, and the north wire the one by which the current leaves the coils, and now
by numbering each magnet forming such a circle, say for the construction of a four
pull motor, from 1 to 12 consecutively, the method of joining up will be readily
understood. It is desirable to begin with the first magnets nearest the positive
wire, and to this I join the south wires of the magnets Nos. 1, 2, and 3, as one
terminal. Then I join the north wire of No. 1 magnet to the south of No. 4, and
the north of this, to the south of No. 7, and so on to magnet No. 10, leaving the
north end of this wire, connected to No. 1 contact slide, of the commutator.
Now I join the north wire of No. 2 magnet, to the south of No. 5, and the north of
this, to the south of No. 8, and so on to No. 11 magnet, the north of which is
connected as before, to No. 2 contact slide, of the said commutator. Then I join
the north wire of No. 3 magnet to the south of No. 6, and the north of this to the
south of No. 9, and so on to No. 12 magnet, leaving the north wire to be connected
to No. 3 contact slide as before. So that the first series of magnets, consists
of Nos. 1, 4, 7, and 10. And the second series, of Nos. 2, 5, 8, and 11, and the
third series of Nos. 3, 6, 9, and 12 magnets.
The commutator c, which is as aforesaid, for the purpose of closing the current
of each respective series, in turns, and may be made of any hard wood or non-
conducting material, is mounted upon a gun metal bush c³, made to fit upon a
reduced end 67, of the armature shaft b, and clips the said shaft to be sufficiently
free to rotate thereon.
The periphery of the commutator has four metal strips let therein, which are
disposed at equi-distances apart, and are marked c, c, c, and c', and are joined
or connected respectively to a metallic facing plate c², with holes c¹, made within it,
wherein the studs 66, of the clutch end ³, take.
This said metallic facing plate c², which is attached to the bush and body of the
commutator, has two other holes passing through it, arranged in such positions, as
to admit of the opposite parts of the metallic strips, being reversed in position
with respect to the rollers of the contact slides, whereby the motor admits of being
driven in an opposite direction if necessary.
These contact slides are three in number, one for each series of magnets, and are
connected to one of the end framings, and insulated from it, by a wooden

page_text: insulator n, and which said contact slides, are marked y, and to which, the return
wires of the series of magnets are connected.
Thus the No. I contact slide, (on the right) is joined to the remaining north
wire, from the magnet No. 10, forming the end of the first series, and the
remaining wire from No. 11 magnet, is joined to the middle contact slide or piece,
and the remaining wire from No. 12 magnet, is joined or connected to the third
contact piece, and the rollers at the terminal ends of each contact slide or piece,
are made to impinge or press upon the periphery of the commutator, at equal
and determinate distances apart.
The distance between each of the 4 metallic strips c, c, c, c', is such that as
one strip is just leaving the third contact slide, the next strip is in connection with
the first contact slide, and before this first metallic strip leaves the first contact
slide, it is in connection with the second contact slide, and before it leaves the
second contact slide, it is in connection with the third contact slide, and before the
first metallic strip leaves the third contact slide, the second metallic strip will be
in connection with the first contact slide, so that the current is never broken, but
always flowing out of one series of magnets into the other, thus giving one
continuous field of attraction.
The positions of the four strips upon the commutator, when taken in relation
to the position of the armature bars, are such that the current always takes the
lead of the said bars, in manner that they are compelled to follow the current.
The
Referring again to the clutch arrangement for reversing the action of the motor
when required, two sets of radially disposed holes are formed within the metallic
facing plate c², wherein pins or studs carried by the clutch, are made to engage
respectively, according to whether being driven forwards or rearwards.
distance between the pair of holes is such, that the stop pin have sufficient space
to allow for the commutator face to make a partial rotation, so as thereby to give
the lead to the four metallic strips, to the other acting positions of the contact
slides.
The commutator is held in position by the forked lever b.
This clutch arrangement may if necessary be applied as a brake, by switching
the current, so as to act in opposition to its former direction.
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 :-
:-
First Making the cores, or the soft iron interiors, of electro magnets, or field
magnets, for electro-motors, in the form of webs, plates, or blades, preferably
tapering wedge-shape from the base to the acting end, whereby a wider and more
extensive field of attraction is thereby obtained, besides occupying less space
while doing duty, than ordinary electro magnets, substantially as described and set
forth.
Secondly-Making electro magnets, of a flattened and elongated figure, and
with the north and south poles of them, connected together by a yoke or cross
bar, whereby a greater magnetic field is augmented, a greater number of magnets
may be allowed to occupy a given space, and a greater power of attraction attained,
substantially as described and set forth."
now
Thirdly In armature, consisting of a plain body part, with bars or longitudinal
and radially directed ribbings, instead of permanent or other magnets, as
employed, whereby the attractive power is increased in the field magnets
employed with it, in manner that when worked in a series, they become energised
in advance of the bars of the said armature employed, and the two back series of
the said magnets, remaining neutral, so as to allow the free advance motion of the -
armature bars, substantially as set forth.
:-
Fourthly The combination with electro or field magnets, of the kind as
described, of a rotary unmagnetized armature, with radiating longitudinally
directed bars, substantially as described and set forth.

page_text: Fifthly Arranging electro or field magnets in series, of which each series may
consist of any number of such magnets, substantially as, and for the purpose, as
described and set forth.
Sixthly-The method or system of wiring and connecting, or connecting
together electro magnets, or electro magnets as described, in series, for the purpose
of magnetizing and demagnetizing such series, in succession, and always in advance
of a rotary armature as described, and which said wires or connections, are
controlled by a suitable commutator.
Seventhly A commutator, consisting of parts and accessory contact slides, or
pieces, substantially as described and set forth.
Eighthly The combination with the magnets in series, and the method of
connection and wiring up of the series, of the armature, and its cognate parts,
substantially as described and set forth.
Ninthly The general construction and arrangement of the parts of electro-
motors, as herein described and set forth.
Dated this 12th day of November 1890.
GEORGE RICHARD POSTLETHWAITE.
By Henry Skerrett,
6, Livery Street, Birmingham, Agent for Applicant.