Improvements in Dynamo-electric Machines.
Year: 1889

page_text: Date of Application, 7th Aug., 1889
Complete Specification Left, 7th May, 1890-Accepted, 2nd Aug., 1890
PROVISIONAL SPECIFICATION.
Improvements in Dynamo-electric Machines.
I. FREDERIK VILHELM ANDERSEN, of 14 Westdown Road, Catford, in the County
of Kent, Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention for Improvements in Dynamo Electric Machines has for its objects to
construct the brushes by which the current is taken off or conducted to a dynamo
electric machine of an improved shape and in an improved manner, to arrange the
brushes in such manner that they shall not be damaged by the rotation of the machine
in either direction, to preserve the original shape of the brushes where they come in
contact with the commutator collector or distributor however great the wear, to firmly
secure the brushes in their holders, to automatically feed forward the brushes as they
and the commutator collector or distributor wear or are otherwise diminished in size,
and to arrange the brushes and their holders in conjunction with magnets in such a
manner that in an electric motor they are automatically adjusted to the requisite angle
on the reversal of the motor.
The brushes are constructed in the shape of an are of a circle and are manufactured
by winding copper or other wire or conducting strips or tape into a round reel and
soldering the wire or strips or tapes together at as many places as the number of
brushes intended to be cut out of the reel, and finally cutting the reel into the intended
number of pieces so that a soldered portion is at or near one end of each piece and the
other end is unsoldered.
The brushes are arranged in such manner that the end that comes in contact with
the commutator is radial to it, consequently they will not be damaged by the rotation
of the machine in either direction and the extent of the surface in contact with the
commutator will not be increased by wear as is the case with brushes constructed in
any of the known ways.
The
The brush holders are secured to brackets pivotted in a frame-hereinafter called
the brush-holder frame-mounted on the end of one of the bearings of the machine
and so that they can be rotated iogether concentrically round the commutator.
centre on which each bracket is pivotted is in the tangent plane to the commutator at
the line of contact of the brush when the commutator has worn down one half of the
total wear allowed and is at a distance from the said line of contact equal to the radius
of the reel from which the brush was cut, and the brush is secured in the bracket in
such a position that it forms an are of a circle at the said centre, consequently it
always bears radially on the commutator however much worn it may be.
The brushes are insulated from the bracket. The jaws in which the brushes are secured
are connected to the bracket by screws passing through insulating bushes and a block of
Each brush is
insulating material is inserted between the bracket and the jaws.
secured in its jaws by a screw passing through the jaws and the brush and a nut is
screwed on the end of the screw and is firmly locked in position by a spring on the
jaws which prevents it from turning.
One end of a long helical spring is secured to the pivot of the bracket or to the
brush holder frame and the other end is secured to the bracket in such a manner that
the brushes are always forced against the commutator, and as the spring is long the
pressure of the brushes against the commutator is practically constant notwithstanding
wear.
A flat plate is secured at one end to the brush-holder frame or to the pivot of the
bracket and a slot is formed in its free end opposite the line of contact of the brush
and at a short distance from the commutator so that the end of the brush passes
through this slot and is kent in the proper shape.

page_text: When applied to an electric motor, an electro or other magnet is connected by links
or levers or in any other suitable manner to the brush-holder frame, in close proximity
to a limb of the field magnets or to a special magnet in such manner that, when the
current is reversed through the field magnets or through the armature in order to
reverse the motor, the action of the said inagnets causes the frame to be moved round
the commutator to the requisite angle for the reversal. The brush holders and brackets
are counterbalanced to reduce the power required to operate them. The special con-
struction of brushes renders it possible to reverse the motor without first bringing it
to a standstill and changing the brushes and the advantage is thus ensured that the
electric power can be employed for quickly reversing the direction of rotation which
in certain cases (for instance when the motor is used for propelling vehicles or boats)
is of great importance. When using the ordinary hitherto known devices of brush
gear on a motor, the motor has to be stopped, the acting brushes raised off the
commutator, and a fresh set of brushes, constructed for acting in the reverse sense,
applied before the power can be put on in the reverse direction. The second pair of
brushes cannot be brought into action until the motor is stopped because they would
be injured by the motor revolving in the opposite direction to that for which they were
made.
Dated thi. 711
C
1900
WHEATLEY & MACKENZIE,
156, Strand, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Dynamo-electric Machines.
1, FREDERIK VILHELM ANDERSEN, of 14 Westdown Road, Catford, in the County
of Kent, 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 for Improvements in Dynamo Electric Machines has for its objects to
construct the brushes by which the current is taken off or conducted to a dynamo
electric machine of an improved shape and in an improved manner, to arrange the
brushes in such manner that they shall not be damaged by the rotation of the machine
in either direction, to preserve the original shape of the brushes where they come in
contact with the commutator collector or distributor, however great the wear, to firmly
secure the brushes in their holders, to automatically feed forward the brushes as they
and the commutator collector or distributor wear or are otherwise diminished in size,
and to arrange the brushes and their holders in conjunction with magnets in such a
manner that in an electric motor they are automatically adjusted to the requisite angle
on the reversal of the motor.
The brushes are constructed in the shape of an arc of a circle and are manufactured
by winding copper or other wire or conducting strips or tape into a round reel and
soldering the wire or strips or tape together at as many places as the number of
brushes intended to be cut out of the reel, and finally cutting the reel into the intended
number of pieces so that a soldered portion is at or near one end of each piece and the
other end is unsoldered.
The brushes are arranged in such manner that the end that comes in contact with
the commutator is radial to it, consequently they will not be damaged by the rotation
of the machine in either direction and the extent of the surface in contact with the
commutator will not be increased by wear as is the case with brushes constructed in
any of the known ways.
The brush holders are secured to brackets pivotted in a frame-hereinafter called
the brush-holder frame-mounted on the end of one of the bearings, of the machine
and so that they can be rotated together concentrically round the commutator. The
centre on which each bracket is pivotted is in the tangent plane to the commutator at
the line of contact of the brush when the commutator has worn down one half of the
total wear allowed and is at a distance from the said line of contact equal to the radius

page_text: of the reel from which the brush was cut, and the brush is secured in the bracket in
such a position, that it forms an arc of a circle at the said centre, consequently it
always bears radially on the commutator however much worn it may be. A flat insulated
guide plate is secured at one end to the brush-holder frame or to the pivot of the
bracket and a slot is formed in its free ond opposite the line of contact of the brush
and at a short distance from the commutator so that the end of the brush passes
through this slot and is kept in proper shape.
The brushes are insulated from the bracket. The holders in which the brushes are
secured are connected to the brackets by screws passing through insulating bushes
and blocks of insulating material are inserted between the brackets and the holders.
Each brush is secured in its holder by a stud fixed in the holder and passing
through the brush and a loose plate and a nut on the end of the stud forces the plate
on to the brush and is firmly locked in position by a spring on the loose plate which
prevents it from turning.
:
One end of a long helical spring is secured to the pivot of the bracket or to the
brush holder frame and the other ond is secured to the bracket in such a manner that
the brushes are always forced against the commutator, and as the spring is long the
pressure of the brushes against the commutator is practically constant notwithstanding
wear.
When applied to an electric motor an electro or other magnet is connected by links
or levers or in any other suitable manner to the brush-holder frame in close proximity
to a limb of the field magnets or to a special magnet in such manner that, when the
current is reversed through the field magnets or through the armature in order to
reverse the motor, the action of the said magnets causes the frame to be moved round
the commutator to the requisite angle for the reversal.
The brush holders and brackets are counterbalanced to reduce the power required to
operate them.
The special construction of brushes renders it possible to reverse the motor without
first bringing it to a standstill and changing the brushes and the advantage is thus
ensured that the electric power can be employed for quickly reversing the direction of
rotation which in certain cases (for instance when the motor is used for propelling
vehicles or boats) is of great importance.
When using the ordinary hitherto known devices of brush gear on a motor, the
motor has to be stopped, the acting brushes raised off the commutator and a fresh set
of brushes constructed for acting in the reverse sense applied before the power can be
put on in the reverse direction. The second pair of brushes cannot be brought into
action until the motor is stopped because they would be injured by the motor revolving
in the opposite direction to that for which they were made.
In the accompanying sheet of illustrative drawings
:-
Fig. 1 is a sectional elevation of a brush holder frame shewing the holders and brushes
in position constructed according to my invention, and
Fig. 2 is a horizontal section of the same.
Figs. 3 and 4 are diagrammatic views shewing an arrangement for automatically
adjusting the position of the brushes on the reversal of the motor.
The brushes a constructed as described above in the shape of an are of a circle are
supported in holders & secured to brackets c pivotted on bolts d fixed in the brush-
holder frame e which is mounted, so as to be capable of rotation concentrically round
the commutator i on a brass sheavej fixed on the hearing of the dynamo electric
machine. The cover plate keeps the frame e in position on the sheave j.
In order to preserve the proper shape of the brushes at the part where they make
contact with the commutator their free ends pass loosely through slots in plates r
secured on the flat sides of the bolts d by screws but insulated therefrom by the
insulating brushest and insulating plates x.
The brush holders and brackets c are insulated from one another by means of
insulating blocks, the screws securing the two together being insulated from the
brackets by means of the bushes y. The brushes a are secured in the holders b by
means of the studs screwed into the holders band over which are passed flat plates m

page_text: forced on to the brushes by the nuts o locked by means of the springs n.
One end of
each of two long helical springs are secured to the frame e and the other ends are
secured to the brackets e so that the brushes a are always forced against the commutator
with a practically constant pressure.
The axis of each bolt d is parallel to the axis of the commutatori and is in a tangent
plane to the commutator at the line of contact of the brushes which are fixed at such
distance from the said axis and in such manner that every point is equidistant from
the said axis consequently they will always bear radially on the commutator notwith-
standing wear. The brackets c are counterbalanced by the hollow pieces y which may
be filled with lead.
In order to adjust the position of the brushes to the requisite angle on the reversal
of the motor, the brush holder frame e is made of iron and is provided with two
extensions which project between the poles of the field magnets at opposite extremities
of a diameter of the armature and are wound in opposite directions with insulated
conducting wire to connected to the terminals of the brushes. The circuit of the field
magnets is connected to the terminals and the armature circuit is connected to the
terminals :.
the
On passing the current to the motor through the terminals v v 22,
extensions u become magnetised and are attracted to one side or the other of their
neutral position, according to the direction of the current through the armature, to set
the brushes to the proper angle. If the current through the armature be reversed to
reverse the motor the extensions u will be attracted to the opposite side to set the
brushes in proper position for the reversal. Stops secured to the brass sheave ; and
acting in conjunction with the nuts of the bolts d limit the motion of the frame e to
the proper angles.
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 arrangement for collecting or distributing the current from or to a dynamo
electric machine consisting of brushes so mounted in brackets pivotted to a frame
capable of motion concentrically round the commutator that all points of the said
brushes are equally distant from the axis of the said pivot which is parallel to the axis
of the commutator and in a tangent plane to the commutator at the point of contact of
the brushes which are forced to bear against the commutator with a practically constant
pressure however short they may have worn substantially as described and for the
purposes specified.
2. The arrangement for collecting or distributing the current from or to a dynamo
electric machine consisting of brushes constructed and arranged so as always to bear
radially upon the commutator notwithstanding wear and having their free ends passing
loosely through slots in insulated plates secured to the brush holder frames so as to
keep the component parts together substantially as described and for the purpose set
forth.
3. The arrangement of brushes whereby the position of the brushes is automatically
adjusted on the reversal of the electric motor consisting of brushes bearing radially on
the commutator and mounted in a frame capable of being rotated concentrically round
the commutator and connected to an electro or other magnet in close proximity to a
limb of the field magnets or to a special magnet so that on the reversal of the current
through the field magnets or through the armature and electro-magnet the frame is
rotated to adjust the brushes to the proper position for reversal substantially as
described.
4. The construction and arrangement of apparatus for collecting or distributing the
current from or to a dynamo electric machine substantially as described with reference
to the drawings.
D
T
1900