Improvements in and relating to Dynamo Electric Machinery.
Year: 1895

page_text: Date of Application, 2nd Apr., 1895
Complete Specification Left, 30th Dec., 1895-Accepted, 8th Feb., 1896
PROVISIONAL SPECIFICATION.
Improvements in and relating to Dynamo Electric Machinery.
We, P. R. JACKSON & CO., LIMITED, Steel Manufacturers, JOSEPH SLATER
LEWIS, Engineer, and GEORGE KEMP, Electrical Engineer, all of Salford Rolling
Mills, Hampson Street, Salford in the County of Lancaster, do hereby declare the
nature of this invention to be as follows :-
Our invention relates to dynamo electric machinery and comprises the various
improvements hereinafter indicated.
The object of our invention is to provide means for constructing the various parts
of dynamos and motors in a cheaper more efficient and stronger manner than here-
tofore. Also to provide an improved method of constructing the field magnets,
bed-plate, brush holders, core, magnet-formers or bobbins, and pedestals of a
dynamo or motor, and a motor or dynamo which shall be. particularly adapted for
use in coal mines and other places where it is desirable to protect them from dust
and to prevent the sparking at the commutator from igniting inflammable and
explosive gases.
According to the first part of our invention we provide for securing to the shaft
washers of sheet metal, preferably iron, of which the core of an armature of
a dynamo or motor is constructed, by means of an improved spider constructed
somewhat as follows, that is to say, it consists of a sleeve to which are secured
three or four or a suitable number of wings or vanes, the radial depth of which is
approximately equal to the internal radius of the washers of which the magnetic
portion of the armature is composed. On or near each end of said wings or vanes,
a radial slot is provided, the longitudinal depth of which is equal to the thickness
of one of the end washers of the armature. The external radius of the said end
washers is equal or approximately equal to that of the armature washers aforesaid;
the central orifice of each end washer being preferably of the same size as the
orifices in the said washers and is of a radius equal to that of the bottom of the slot
in the ends of the wings or vanes.
In the internal circumference of the end
washers are formed slots corresponding in number, position and size to the wings
or vanes of the spider. In building up the armature, one end washer or a number
of the core discs is or are slipped on the wings or vanes from the end, the said
wings or vanes passing through the slots formed in the internal circumference
of the said end washer or core dises until the same coincides or coincide with
the slots in the ends of the wings. The washer or core discs is or are turned
round through the slots in the ends of the wings until the slots in the internal
circumference no longer coincide with those in the wings or vanes, The discs
or washer may be secured in this position if desirable by a screw or other
suitable device. The armature washers, together with paper or other insulating
washers if required, are now slipped on to the spider from the other end in the
usual manner until a sufficient number are in position. They are now compressed
longitudinally by any suitable means, and the other end washer or discs slipped
on and turned round in the manner hereinabove described with reference to the
first end washer or discs. When the second end washer or discs is or are in position
the pressure on the armature washers is removed, and the said washers consequently
expand longitudinally, and are thereby very tightly gripped between the two end
plates or discs.

page_text: According to the second part of our invention, we provide an improved brush-
holder for dynamo electric machines by means of which the brushes can be
adjusted on the commutator with very great case and accuracy. In carrying out
this part of our invention we provide on each end of the rocker, which may be of
any ordinary type, a spindle on which is supported a disc or circular box of
suitable size. On the periphery of said disc or box is pivoted a rocking saddle
or brush carrier proper through which the brush rod is adapted to slide, the
saddle being provided with an adjustable spring which tends to press the brush
against the commutator. At the opposite end of the saddle is pivoted a rod or strip
adapted to slide in a groove provided in the said disc or box, the said rod or strip
being notched at the end, or otherwise formed, so as to be capable of engaging
with a spring catch bolt. When the saddle or carrier is tilted on its pivot against
the force of the spring aforementioned, so as to withdraw the brush from the
commutator, the rod or strip engages with the spring catch bolt thereby preventing
the said spring from bringing the brush into contact with the commutator again.
When the spring catch bolt is operated to release the said rod or strip the sait
spring acts to apply the brush to the commutator. In some instances we form the
catch so that a downward pressure has to be exerted on the said rod or strip before
the catch bolt can be released. The brush is preferably mounted and clamped in
a rod of circular section adapted to turn in a circular hole in the carrier or saddle.
By this means we are enabled to use very short brushes, and also to rotate the brush
on its axis in order that it may be applied to touch the commutator in a line
parallel to the axis of the armature. The brush is fed forward to the commutator
by means of a screw or other suitable device. When we employ carbon brushes,
we prefer to provide saw-cuts in the end thereof which is to be clamped to the rod
aforementioned previous to electro-plating the said brushes. This prevents the
pressure of the clamp from cracking or splitting the brush. We preferably make.
electrical connections between the said saddle and the spindle or box by means of
flexible copper cable or the like which is soldered or otherwise secured at each
end to the saddle and spindle or box. The brush-holder is adjusted laterally as
follows: The spindle is screw threaded and nuts are provided thereon which grip
the box or boxes (as for instance where more than one brush-holder is used) in any
desired position.
In the third part of our invention we provide improved self-oiling pedestals in
which the shaft of a dynamo or motor is supported. The said pedestals have at
the bottom a reservoir for oil, which is transferred or thrown to an oil cup at the
top of the pedestal above the bearing in the manner hereinafter described. For
this purpose the bearing is furnished with a slot perpendicular to its axis, which
slot forms communication between the said oil reservoir and the said oil cup.
A paddle-wheel fixed to the shaft supported in the bearing rotates in this slot and
gradually sweeps or throws the oil from the reservoir to the said cup, from which
cup it descends by suitable holes or grooves to the top of the shaft. The waste
oil, which exudes from the ends of the bearing is caught in suitable channels and
led back to the reservoir below in a well-known manner.
In the fourth part of our invention we provide for constructing the bed-plates,
field magnets, pole-pieces, and if necessary the pedestals for supporting the spindle
in an improved manner as follows:-that is to say, 'we cast the whole of the said
parts, which may be of steel for instance, in one piece and then saw, or otherwise
divide the casting in such places as is necessary in order to place the field magnet
coils in position on the cores. Before so dividing the parts, we drill and tap holes
for the bolts which are to unite the said parts together. By these means we reduce
the number of separate parts and to a large extent obviate the necessity of marking
out and locating the positions which the various bolts and parts are to occupy,
which generally occasions considerable expenditure of time and.labour.
We very often design the main frame or the bed-plate in such a manner that the
same can be readily fixed against the wall or to the beams of a ceiling or against
a pillar without having to resort to the use of special brackets, and in connection

page_text: therewith, we sometimes provide a counter-shaft driven, preferably, by bevel
gearing, and arranged to turn on an axis.which is coincident with the axis of the
dynamo or motor shaft. By these means we are enabled to save very considerable
floor space and to very readily adjust the belt to run in any direction.
Where the dynamo or motor is supported or clamped to a circular pillar it can
be readily turned round the same by slacking the clamping screws, and an axial
or radial counter-shaft such as that hereinabove described is not required.
Where a dynamo is so supported that the shaft thereof is vertical, we provide a
foot-step bearing for the lower end of any suitable type, preferably with ball
bearings. We, however, arrange for lubricating the said bearing by means of
oil from a cup or vessel at the top of the shaft, the oil travelling through the shaft
to the lower bearing through an axial hole provided for that purpose.
We pre-
ferably provide an annular cup, with turned-in.edges, encircling the dynamo or
motor shaft just below the top bearing. The lowest part of the interior of the cup
communicates by a radial passage with the axial hole in the shaft so that oil flowing
from the top bearing is caught by the annular cup and passed through the axial
hole to the lower bearing. By this means we prevent the commutator and
armature being fouled with oil. The turned-in edge of the annular cup also
prevents the oil being throw therefrom when the spindle is rotating.
In the fifth part of our invention, we provide for enclosing the dynamo or motor
in the following manner: We provide a cover, preferably of non-magnetic
material, for the machine, which consists merely of a top plate cut approximately
to the shape of the bed-plate of the machine. The sides of the case are formed of
two or more sheets of metal which are bent to the shape of the top plate and the
bed-plate of the machine. These may be secured to the bed-plate and to the.top
plate by strips. of metal of angular section if desired by bolts or other means.
a modification of this part of our invention, we arrange that the pedestals
supporting the shaft shall be of square or rectangular shape, so as to form the ends
of-the case.
The case will then consist, preferably, of six pieces, viz.-a top,
bottom, two ends, and two sides. We prefer to use zinc for such cases; any other
suitable metal however may be employed if desired. In such enclosed dynamos
when used in coal mines the case may become, after some time has elapsed, filled
with an explosive or inflammable gas. In order therefore to prevent explosions we
provide for blowing out such explosive gases before starting the machine. We
accomplish this as follows:- -We provide a cylinder of compressed air and connect
the saine with one side of the case. An exit valve for the foul air and gases inside
the casing is also provided. When operating, the compressed air from the cylinder
rushes through the inside of the case and sweeps out through the exit valve any
foul air and gases which may have collected therein. This is done periodically
before the machine is started, and preferably once a day, or at the beginning of
every shift.
We rotate the brushes inside the case by means of suitable gearing. We also
provide, in the case, windows and doors for use when the machines are not running,
and we arrange these so that they cannot be operated when the dynamo or motor
is excited. This we accomplish by means of iron bolts or catches which are
attracted and held by the field magnets when they are excited. The cables.are
led into the case through stuffing boxes.
The magnet bobbins or formers upon which the field magnet wire is wound we
construct as follows :- We provide washers of wood, fibre, or of any suitable
material. These washers we connect by sheet metal screwed to the said washers.
This metal is provided in halves and so formed that by taking out the screws at
the ends they may be removed, and the coil of wire detached for examination or
repair.
In the last part of our invention, we provide improved means for preventing
sparking at the commutator. For this purpose we arrange a coil or coils of wire
of suitable dimensions on the pole-pieces in the manner hereinafter described so as.
to neutralise the cross-inductive effect of the current flowing through the amature

page_text: coils. The effect of arranging this coil or coils in this position is that the current
flowing therein will oppose the currents in the coils that are being short-circuited
by the brushes, thereby preventing the spark due to such short-circuiting.
The coils are arranged on the pole pieces at right angles to the air spaces of
the machine, one coil being placed on each neck of the poles.
The current is arranged to flow in the coils on the pole-pieces, in such a manner
that the magnetic field due to such currents is opposed in direction and equal or
variable in strength to the magnetic field produced by the current flowing in the
armature coils. We thereby ensure that the magnetic field in which the armature
is rotating, is that due to the field magnet coils alone. By this means we entirely
prevent sparking at the commutator, and we moreover save a considerable amount
of copper owing to the fact that fewer turns are required on the field magnet coils
in consequence of the inductive effect of the armature being neutralised.
Dated this 2nd day of April 1895.
W. P. THOMPSON & Co.,
31, High Holborn, London, W.C., Patent Agents for the Applicants.
Improvements in and relating to Dynamo Electric Machinery.
We, P. R. JACKSON & CO., LIMITED, Steel Manufacturers, JOSEPH SLATER
LEWIS, Engineer, and GEORGE KEMP, Electrical Engineer, all of Salford Rolling
Mills, Hampson Street, Salford, in the County of Lancaster, 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:-
Our invention relates to dynamo electric machinery and comprises the various
improvements hereinafter indicated.
The object of our invention is to provide means for constructing the various parts
of dynamos and motors in a cheaper more efficient and stronger manner than
heretofore. Also to provide an improved method of constructing the field magnets,
bed-plate, brush holders, core, magnet-formers, or bobbins, and pedestals of a
dynamo or motor, and a motor or dynamo which shall be particularly adapted for
use in coal mines and other places where it is desirable to protect them from dust
and to prevent the sparking at the commutator from igniting inflammable and
explosive gases.
In order that our invention may be clearly understood we will now proceed to
describe the same with reference to the accompanying drawings in which
Figure 1 is an elevation the upper half being in section of the core of an
armature constructed according to our invention the armature shaft being
removed.
Figure 2 is an end elevation of the same.
Figure 3 is an elevation partly sectional of a brush holder constructed according
to our invention parts being removed to shew the internal construction and
Figure 4 is a plan of the same.
Figures 5 and 6 are views similar to Figure 3 shewing modified forins of
brush-holder.
Figure 7 is a vertical central section of our improved self-oiling pedestal and
Figure 8 a section on the line 8-8 Figure 7 the shaft being removed.
Figure 9 is a side elevation and
Figure 10 an end elevation of a dynamo frame constructed according to our
invention.
Figure 11 is an elevation of the armature and shaft of a vertical dynamo shewing
our improved method of oiling the footstep bearing.

page_text: Figure 12 is a detail view hereinafter explained.
Figure 13 is a perspective view of our improved bobbin for field magnet coils.
Referring now to Figures 1 and 2 A, A are sheet metal discs composing the
ármature core. These are secured to the shaft by a spider B consisting of a
sleeve B¹, to which are secured three or four or a suitable number of wings or-
vanes B, the radial depth of which is approximately equal to the internal radius:
of the iron washers of which the magnetic portion of the armature is composed..
On or near each end of the said wings or vanes, a radial slot B³ is provided, the
longitudinal depth of which is equal to the thickness of one of the end washers of
the armature. The external radius of the said end washers is equal or approximately
equal to that of the armature washers aforesaid; the central orifice of each end
washer being of a radius equal to that of the bottom of the radial slot B in the
ends of the wings or vanes aforementioned. In the internal circumference of the
end washers are formed slots A' corresponding in number, position and size to the
wings or vanes of the spider.
Instead of using special end washers a suitable number of thin plates like the.
armature discs may be used cut to the proper shape and size and rivetted.
together.
In building up the armature, one end washer or a number of thin dises as.
aforementioned is or are slipped on the wings or vanes from the end, the said wings.
or vanes passing through the slots formed in the internal circumference of the said
end washer or discs until the same coincides or coincide with the slots in the ends:
of the said wings or vanes. The washer or discs is or are turned round through
the slots in the ends of the wings until the slots in the internal circumference no.
The discs.
longer coincide with those in the wings or vanes as shown in Figure 2.
or washer may be secured in this position if desirable by a screw B₁ or other-
suitable device. The armature washers, together with paper or other insulating
washers if required, are now slipped on to the spider from the other end in the
usual manner until a sufficient number are in position. They are then compressed
longitudinally by any suitable means, and the other end washer or discs slipped on.
and turned round in the manner hereinabove described with reference to the first
end washer or discs. When the second end washer or discs is or are in position the-
pressure on the armature washers is removed, and the said washers consequently
expand longitudinally, and are thereby very tightly gripped between the two end
plates or discs.
According to the second part of our invention, we provide an improved brush--
holder for dynamo-electric machines by means of which the brushes can be adjusted.
on the commutator with very great ease and accuracy. In carrying out this.part.
of our invention we provide on each end of the rocker, which may be of the ordinary
type, a threaded and key-grooved spindle C Figure 3 on which is supported by a.
feather key C¹ a disc or circular box D of suitable size. On the periphery of said:
dise or box is pivoted a rocking saddle D¹ through which the brush rod or holder E.
is adapted to slide, the saddle being provided with an adjustable spring which tends
to press the brush against the commutator. To the end of the saddle is pivoted a.
rod or strip D adapted to slide in a groove provided in the disc or box D, the
said rod or strip is formed with a projection D³ which can engage with a spring
catch bolt F. When the saddle D' is tilted on its pivot against the force of the
spring aforementioned, so as to withdraw the brush from the commutator, the rod
or strip D engages with the spring catch bolt F thereby preventing the said spring-
from bringing the brush into contact with the commutator again. When the
spring catch bolt F is operated to release the said rod or strip the said spring acts.
to apply the brush to the commutator.
In some instances we form the catch D' so that a downward pressure has to be
exerted on the rod or strip D' before the catch bolt can be released. In the
drawing the spring for bringing the brush against the commutator is applied to
the lower end of the strip as shewn at G being adjusted by means of a screw and.
lock nuts G¹. In some instances we dispense with the rod or strip D' and apply.

page_text: the spring direct to the saddle a part of which saddle may be inserted in the
aforesaid box for that purpose. In this case we employ a rocking-catch to keep
the brush from touching the commutator, the catch engaging with that portion of
the saddle which is inside the box D. The brush is preferably mounted and
clamped in a sliding rod E of circular section adapted to partially turn in a
circular hole in the carrier or saddle D¹. By this means we are enabled to
rotate the brush on its axis in order that it may be applied to touch the commutator
in a line parallel to the axis of the armature. The brush is moved forward and
backward to the commutator by means of a screw or other suitable device as shewn
at E and the tip is prevented from turning up by a spring E' which is clamped in
the desired position by the screw or set pin E³ that secures the brush to the sliding rod.
When we employ carbon brushes, we prefer to provide saw-cuts in the end
thereof which is to be clamped to the rod aforementioned previous to electro-
plating the said brushes. This prevents the pressure of the clamp from cracking or
splitting the brush. We preferably make electrical connection between the said
saddle and the spindle or box by means of flexible copper cable or the like which
is soldered or otherwise secured at each end to the saddle and spindle or box. The
brush-holder is adjusted laterally as follows:-Nuts C2 are provided on the
spindle C which grip the box D or boxes (as for instance where more than one
brush-holder is used) in any desired position. When two or more brush-holders
are used in one spindle distance collars or sleeves are employed to keep the brush
holders apart.
In Figures 5 and 6 we shew modified forms of our improved brush-holders in
which the box or disc D is dispensed with the part D being mounted direct on the
stud at the end of the rocker. Referring now to Figure 5 said stud has a collar C³
secured thereon which carries the notch or catch C. The lever D2 with its
projection D is mounted as shewn. G'is a spring secured at one end to the
collar C and at the other end to the carrier or saddle D' which tends to bring the
brush towards the commutator. In Figure 6 a form more suitable for use with
carbon brushes is shewn in which no provision is made for tilting the brush-holder
on its stud. The spring G³ however maintains the brush closely applied to the
commutator. As the brush wears the tension in the spring is maintained by turning
the nut E' so as to keep the spring of the proper length. The slot E through
which the pin D³ passes is made wide enough to admit of the tube E being
rotated a sufficient amount so as to bring the brush to bear properly on the
cominutator.
In the third part of our invention we provide improved self-oiling pedestals in
which the shaft of a dynamo or motor is supported. As shewn in Figures 4 and 5
the said pedestals have at the bottom a reservoir H for oil, which is transferred or
thrown to an oil cup or gallery I at the top of the pedestal above the bearing in
the manner hereinafter described. For this purpose the bearing is furnished with
a slot J perpendicular to its axis which slot forms communication between the oil
reservoir and the oil cup or gallery I. A paddle-wheel or plain collar K fixed to
or running loose on the shaft supported in the bearing rotates in this slot and
gradually sweeps or throws the oil from the reservoir to the cup or gallery from
which cup it descends by suitable holes or grooves I' to the top of the shaft. The
waste oil, which exudes from the ends of the bearing is caught in suitable channels
such as Hand led back to the reservoir below in a well-known manner. In place
of the two collars generally used on the shaft at either end of one of the said
pedestals for preventing lateral motion of the shaft we employ one collar and in
the centre of the pedestal. This collar acts as one of the paddle wheels or collars
for throwing up the oil to the cup or gallery or a paddle wheel or collar may be
fixed over the said shaft collar proper. This arrangement enables us to employ
V-collars on the shaft at the ends of the pedestals as shewn at L for example, thus
preventing the oil from flowing along the shaft such oil being thrown from
the shaft by the centrifugal action of the V-collars and caught in the channels H'.
In the fourth part of our invention we provide for constructing the bed-plates,

page_text: field magnets, pole-pieces, and if necessary the pedestals for supporting the spindle
in an improved manner as follows:-that is to say, we cast the whole of the said
parts, which may be of steel for instance, in one piece, and then saw, or otherwise
divide the casting in such places as is necessary in order to place the field magnet
coils in position on the cores. Before so dividing the parts, we drill and tap
holes for the bolts which are to unite the said parts together. By these means
we reduce the number of separate parts and to a large extent obviate the
necessity of marking out and locating the positions which under ordinary
conditions the various bolts and parts occupy, which generally occasions con-
siderable expenditure of time and labour, and forms a source of mechanical
weakness. The design we prefer to employ is shewn in Figures 9 and 10
where K. K are the magnet cores K' the bed-plate and K2, K2 the pole-pieces,
these latter are held and adjusted in position by short bolts K, K³ the heads
of which are received in recesses K, K' formed for that purpose in the
pole-pieces.
We very often design the main frame or the bed-plate in such a manner that
the same can be readily fixed against the wall or to the beams of a ceiling or
against a pillar without having to resort to the use of special brackets, and in
connection therewith, we sometimes provide a counter-shaft driven, preferably, by
bevel gearing, and arranged to turn on an axis which is coincident with the
axis of the dynamo or motor shaft. By these means we are enabled to save
very considerable floor space and to very readily adjust the belt to run in any
direction.
Where the dynamo or motor is supported or clamped to a circular pillar it can
be readily turned round the same by slacking the clainping screws, and an axial or
radial counter-shaft such as that hereinabove described is not required.
Where a dynamo is so supported that the shaft thereof is vertical, we provide
a foot-step bearing for the lower end of any suitable type, preferably with ball
bearings. We, however, arrange for lubricating the said bearing as shewn in
Figure 11 by means of oil from a cup or vessel L at the top of the shaft, the oil
travelling through the shaft shewn at M to the lower bearing through an axial
hole M provided for that purpose. We preferably provide an annular cup, N with
turned-in edges, N¹ encircling the dynamo or motor shaft just below the top
bearing. The lowest part of the interior of the cup communicates by a radial
passage M2 with the axial hole M' in the shaft in such manner that oil flowing
from the top bearing is caught and transmitted by the annular cup and passed
through the axial hole to the lower bearing. By this means we prevent the
commutator and armature being fouled with oil. The turned-in edge of the
annular cup also prevents the oil being thrown therefrom when the spindle is
rotating.
In Figure 12 we shew a modification in which the cup N is not secured to the
shaft but is independently supported a pipe N delivering the waste oil to a suitable
receptacle provided for the purpose. The shaft has a collar M³ secured thercon
which discharges any oil on the shaft by centrifugal force into the cup N.
A groove M in the underside of the collar prevents the oil from creeping round
and down the shaft to the commutator when the dynamo is not running.
In the fifth part of our invention, we provide for enclosing the dynamo or motor
in the following manner-We provide a cover, preferably of non-magnetic
material, for the machine, which consists merely of a top plate cut approximately
to the shape of the bed-plate of the machine. The sides of the case are formed
of two or more sheets of metal which are bent to the shape of the top plate and
the bed-plate of the machine. These may be secured to the bed-plate and to the
top plate by strips of metal of angular section if desired by bolts or other means.
In a modification of this part of our invention, we arrange that the pedestals
supporting the shaft shall be of square or rectangular shape, so as to form the ends
of the case.
The case will then consist, preferably, of six pieces, viz. :—a top,
bottom, two ends, and two sides. We prefer to use zinc for such cases; any other

page_text: suitable metal however may be employed if desired. In such enclosed dynamos
when used in coal mines the case may become, after some time has elapsed, filled
with an explosive or inflammable gas. In order therefore to prevent such
explosions we provide for blowing out such explosive gases before starting the
machine. We accomplish this as follows:-We provide a cylinder of compressed
air and connect the same with one side of the case. An exit valve for the foul air
and gases inside the casing is also provided. When operating, the compressed
air from the cylinder rushes through the inside of the case and sweeps out through
the exit valve any foul air and gases which may have collected therein. This is
done periodically before the machine is started, and preferably once a day, or at
the beginning of every shift.
We rotate the brushes inside the case by means of suitable gearing. We also
provide, in the case, windows and doors for use when the machines are not running,
and we arrange these so that they cannot be operated when the dynamo or motor
is excited. This we accomplish by means of iron bolts or catches which are
attracted and held by the field magnets while electrically excited. The cables are
led into the case through stuffing boxes, thus making the whole machine perfectly
gas-tight and air-tight.
One of our improved magnet bobbins or formers upon which the field magnet
wire is wound are shewn in Figure 13, O, O are washers of wood, fibre, or of any
suitable material, connected by sheet metal pieces P, P secured to the said
washers by screws P', PI. It will be readily seen that by taking out the screws
at the ends of the metal pieces they may be readily removed from the washers and
the coil of wire detached from the bobbin for examination or repair.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. For a dynamo-electric machine, an armature having a core consisting of discs
supported on a spider constructed substantially as described.
2. For a dynamo-electric machine a brush-holder in which the brush is mounted
on a saddle or carrier which is pivoted at or near the edge of a disc capable of
rotation on a stud fixed to the rocker, substantially as described.
3. A brush so mounted on its holder as to be capable of rotation on an axis
perpendicular to the shaft of the machine and parallel with the length of brush for
the purpose specified.
4. A brush-holder constructed substantially as described with reference to
Figures 3 and 4 or to Figure 5 or to Figure 6 of the accompanying drawings.
5. The combination with a pedestal having a reservoir for oil in its base and a
cup or gallery at the top, of a shaft rotating in bearings in the pedestal and a ring
on the shaft secured or not thereto adapted to convey the oil from the said
reservoir to the said cup or gallery whence it is supplied by suitable channels to
the bearing, substantially as described.
6. The method of constructing the iron parts of a dynamo machine by casting
the same in one piece and then dividing the casting in the desired places by any
suitable means, substantially as, and for the purpose, specified.
7. A dynamo having its fixed magnetic parts constructed substantially as
described with reference to Figures 9 and 10 of the accompanying drawings.
8. The arrangements for lubricating the footstep bearing of a vertical shaft
which consists in supplying the oil through an axial channel in the shaft, either
with or without an annular cup for catching the waste oil from the top bearing
and transmitting it to the axial channel or to another receptacle, substantially as
described.
9. The method of preventing explosions inside the casing of an enclosed
dynamo-electric machine, which consists in blowing out the air and gases contained
in said casing before the machine is started substantially as described.
10. In an enclosed dynamo electric machine making the bolts or catches of the

page_text: doors of the casing of magnetic material so that when the magnets are excited
said bolts or catches cannot be released, substantially as, and for the purpose
specified.
11. For field magnet coils, bobbins or formers constructed substantially} as.
5 described with reference to Figure 13 of the accompanying drawings.
Dated this 30th day of December 1895.
W. P. THOMPSON & Co.,
31, High Holborn, London, W.C., Patent Agents for the Applicants.