Improvements in Dynamo Electric Machines.
Year: 1891

page_text: Date of Application, 12th May, 1891
Complete Specification Left, 12th Feb., 1892-Accepted, 26th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in Dynamo Electric Machines.
I GEORGE JOSEPH PHILPOTT of 39, Marlborough Place, Brighton, in the
County of Sussex, Electrical Engineer, do hereby declare the nature of this
invention to be as follows:-
The object of the said invention is to provide means of so connecting dynamos
that they shall whilst remaining self-exciting supply electric currents from their
armatures of three kinds direct alternating and pulsatory. This object may be
effected with a machine built in the usual manner either shunt series or compound
wound and the invention may be used to make an alternating current machine
self-exciting.
The method by which the connections are made are as follows, taking the case of
a two-pole Gramme machine as an example.
The brushes are set as usual upon a sectional commutator of any ordinary type
and in any desired position, from these brushes a continuous current is collected
which is used to excite the field magnet of the said machine and also to supply an
external circuit. Upon the spindle of the said machine are fixed tw) insulated
collector rings, one of the said rings is connected to any single segment of the
commutator, the other of the said rings is connected to a segment exactly opposite
to the first, and on the other side of the commutator. From brushes set 'on the
said rings may be collected an alternating current and the machine will still remain
self-exciting.
By using one pole of the continuous circuit and one of the alternating circuit a
pulsatory current may be collected.
From this description the connections of a multipolar machine may easily be
understood.
Doted this ih ur of May 1801
•
GEORGE JOSEPH PHILPOTT.
COMPLETE SPECIFICATION.
Improvements in Dynamo Electric Machines.
1, GEORGE JOSEPH PHILPOTT, of 39 Marlborough Place, Brighton, in the
County of Sussex, 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:-
This invention has reference to improvements in dynamo electric machines,
whereby such a machine, whilst remaining self-exciting, shall be capable of
supplying, at will, electric currents from its armature of three kinds viz., direct,
alternating, and pulsatory. For this purpose, the machine is constructed with
insulated rings and collecting brushes in addition to a commutator and brushes
therefor, the several parts and their connections being arranged as I will now
proceed to describe, taking as an example a two pole shunt wound Gramme
imachine.
The commutator brushes are set in the usual manner and in any desired position
upon the sectional commutator which may be of any ordinary or suitable type, and
from the brushes a continuous current is obtained in the usual way which can be
used to excite the field magnet of the said machine and also to supply an external
circuit. Upon the spindle of the said machine are fixed two insulated collector
1

page_text: rings, one of which is connected to any segment of the commutator or to the
armature coil in connection therewith, whilst the other is connected to a segment
of the commutator opposite to the first, and on the other side of the commutator,
or to the armature coil in connection with this segment. From brushes arranged
in rubbing contact with the said rings may be collected an alternating current, and
the machine will still remain self exciting.
By using one pole of the continuous circuit and one of the alternating circuit a
pulsatory current may be obtained.
From the following description the connections for a multipolar machine may
easily be understood.
My invention may be applied to a shunt wound or to a separately excited machine
built in the usual manner.
Fig. 1 of the annexed sheet of drawing shews diagrammatically a dynamo
machine constructed according to my invention, and further illustrates various
methods by which the currents it generates, may be usefully employed.
The armature is wound after the usual fashion of a Gramme ring, and con-
nected in the ordinary way to the commutator 2, on which there press two
brushes 3 and 4. From these brushes there proceed the external mains 5 and 6,
and the connections 7 and 8 of the shunt wound field magnet coils 8* and through
these mains and field magnet coils a continuous current will flow in the usual
way.
From two opposite coils of the armature, connections are made to two insulated
collecting rings 9 and 10 on the axis, as shown by the lines 9" and 10" respectively;
or the connection may of course be made to two opposite segments of the commutator.
These rings are each pressed upon by a brush 9 or 100 connected to an external
circuit.
11 represents a battery of accumulator cells; 12 a transformer, 13 a number of
lamps or other apparatus that can be driven or actuated by an alternating current;
14 a number of lamps or other apparatus that can be driven or actuated by a
continuous or by a pulsatory current, and 15 are switches. The battery 11 is fed by
a continuous current passing from the brush 4, through the conductor 6 and the
battery and back through the conductors 15 and 5 to the brush 3 in the direction
indicated by the arrows a. The transformer 12 is traversed by a primary
alternating current starting (say) from the ring 9 and flowing by the conductor 16,
the coils of the transformer, and the conductor 17 back to the ring 10 in the
direction indicated by the arrows b. The secondary coil of the transformer
supplies the lamps 13 or other translating devices.
When the devices 14 are to be worked by a continuous current from the machine,
the switches are so arranged that current flows say from the commutator brush 4
through the mains 6, devices 14 and main 5 to the brush 3 in the direction indicated
by the arrows e. When the devices 14 are to be driven or actuated by a pulsating
current the main 6 is connected as for example by a switch at 15 to one of the
collector brushes say 10 so that the pulsatory current produced between the
brushes 3 and 10" will flow say in the direction of the arrows d through the mains 6
and 5 and devices 14. The devices 14 may also, with the arrangement shewn, be
fed with a continuous current from the battery 11, this current flowing in the
direction of the arrows e.
Thus with the construction described, if the armature 1 be driven by mechanical
power, there may be obtained and utilized, at the same time, continuous, alternating
and pulsatory currents. Also if the machine be disconnected from the motor for
driving it, it can be driven by a current from the previously charged battery 11, at
which time each of the three kinds of currents hereinbefore mentioned can still be
obtained from its brushes.
It will be obvious from the foregoing description that two or more pairs of
opposite points on the armature winding, or opposite pairs of commutator segments,
may be connected to independent pairs of rings in the manner described.
With a dynamo such as described, there will be a complete period
--) of

page_text: current for each rotation of the armature.
frequency will of course be increased.
With a multi-polar dynamo the
Fig. 2 is a diagrammatic view of a four pole dynamo having an armature with
Mordey's winding the arrangement of which is well understood by electricians.
In such an arrangement the two insulated collector rings 9 and 10 which, for
convenience, are shewn as arranged concentrically, but which in practice would be
arranged as in Fig. 1, may be connected to any pair of the commutator segments
as for example 20 and 2 upon which for the time being the commutator brushes 3
and 4 bear, or to the parts of the armature winding directly connected to these
segments. Or two pairs of insulated rings may be employed, one pair connected
say to 2 and 2 and the other pair to 2° and 2.
Fig. 3 is a diagrammatic view of a four pole dynamo having an armature with
In this case
Perry's winding the arrangement of which is also well understood.
the insulated collector rings 9 and 10 may be connected to the commutator
segments 2 2d or direct to the armature coils connected thereto, or to any other
pair of conmutator segments upon which the commutator brushes 3 and 4
simultaneously bear during the rotation of the armature; or to two pairs of such
segments as for example 2-2ª and 2'-2'.
Thus it will be seen that in each case the pair of insulated rings are connected
to a pair of commutator segments (or to the parts of the armature winding directly
connected to these segments) upon which the commutator brushes during the rotation
of the commutator will, for the time being, simultaneously bear.
When the field magnet or magnets of the dynamo are separately wound, the
whole of the current flowing through the armature winding may be obtained as an
alternating current.
By my invention when the load on an external circuit is small, the motor
ordinarily employed for driving the dynamo supplying such circuit can be thrown
out of action, and the dynamo be driven by an electric current from any suitable
source, as from the secondary battery 11 previously charged by a continuous
current produced by the dynamo when it was being driven mechanically. Thus
the cost ordinarily involved when running dynamos with a comparatively small
external load can be considerably reduced.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
1. In a shunt wound or a separately excited dynamo electric machine, a com-
mutator and insulated collecting rings so connected to the armature coils either
direct or through commutator sections that at will either (1) the entire current
generated in the said coils can be obtained from the commutator as a continuous
current; or (2) the said entire current can be obtained from the collecting rings
as an alternating current; or (3) part can be obtained from the commutator as
continuous current and part from the collecting rings as alternating current;
or (4) part can be obtained from the commutator as continuous current, and part
as pulsatory current by using the commutator and a collecting ring jointly;
or (5) continuous, alternating and pulsatory currents can be obtained simultaneously,
whether the dynamo be driven, mechanically or electrically.
2. A dynamo electric machine of the kind referred to in the preceding claim,
constructed substantially as hercinbefore described with reference respectively to
and shewn in Fig. 1; in Fig. 2; and in Fig. 3 of the drawings annexed.
18th day of habowary 1800
G. J. PHILPOTT.
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.