Improvements in Dynamo Electric Machines.
Year: 1891

page_text: Date of Application, 24th Feb., 1891
Complete Specification Left, 24th Nov., 1891-Accepted, 24th Dec., 1891
PROVISIONAL SPECIFICATION.
Improvements in Dynamo Electric Machines.
I, JOHN AUGUSTINE KINGDOx of 29 Marlborough Hill, St. John's Wood in
the County of London, Electrical Engineer do hereby declare the nature of this
invention to be as follows:-
:-
My invention relates chiefly to dynamo electric machines constructed to generate
low tension continuous currents for the purposes of electrodepositing metals and of
electric welding.
The ordinary forms of armature such as the Gramme ring or the Siemens drum
have their windings connected in series and are suitable for voltages of from five
to say 500 volts, but are unsuitable for machines of low voltage such as one or
two volts.
In order to construct an efficient and practical dynamo for such low voltages
I wind the armatures of my improved machines with coils of wire quite distinct
and insulated from one another instead of being connected each with the next as in
the Gramme & Siemens armatures.
The commutator of iny improved dynamo may have twice as many sections as
there are distinct windings on the armature in which case, when the machine has
two poles the ends of each winding are connected with opposite sections of the
commutator.
be
Two sets, each consisting of a number of brushes of suitable construction, may
arranged to rub against the commutator so as to make contact with the sections
connected with those coils which are passing in front of pole pieces and therefore
cutting lines of force, and to collect the current from all these coils in parallel ;
one set of brushes being on one side of the commutator & collecting the positive
current, the other set of brushes collecting the negative current. Or I may employ
two large brushes, blocks or other suitable rubbing collectors.
In some cases I may employ two commutators, one on each side of the armature,
corresponding sections of each being connected with the two ends of the bars or
windings on the armature. Each commutator has then as many sections as the
armature has windings, and there are four sets of brushes, two making contact on
each commutator.
Each bar or winding on the armature and its two commutator sections are
insulated from the rest.
I thus construct a dynamo which has the voltage of one bar or winding and
gives the sum of the currents generated in all the active coils or windings.
The brushes, instead of being thin and making contact with only one or two
sections of the commutator as is usually the case, may be thick or many in number,
and may extend round and make contact with a considerable part of the commutator
the proportion depending on the amount of the armature embraced by the pole
pieces of the magnets.
Instead of connecting all the active windings of the armature in parallel by means
of a set of brushes mounted on one metal frame, I may insulate one or more brushes
from the rest and connect them with separate circuits.
Arrangements may be made for shifting the brushes so as to alter their lap
and lead so as to avoid sparking and obtain the maximum output & efficiency.
The armature may be constructed, with the modifications herein before described,
in the form of the Siemens drum armature or similar to a Gramme or Paccinotti
ring or to any other known type of armature.
The poles, which in small machines are two in number, and magnets may be of any
known type. In large machines I may use four or any higher even number of poles,

page_text: in which case I increase the number of brushes and modify the connections of the
windings with the commutator sections.
The magnets may be excited by current from the machine either by shunt or
series or compound windings, or they may be excited by the current from a smaller
dynamo, which may have its magnets wound with a winding carrying the current
of the main dynamo.
·
Where a number of brushes are employed they may be mounted independently
on a frame and one in advance of the other so as to touch different sections of the
commutator. Two or more such frames may be used, side by side.
Dated thin 21th 1 of a 1001
J. A KINGDON.
Improvements in Dynamo Electric Machines.
1, JOHN AUGUSTINE KINGDON of 29 Marlborough Hill, St. John's Wood 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 chiefly to dynamo electric machines constructed to generate
continuous currents of low electro motive force for the purposes of plating and
electro depositing metals and of electric welding.
Fig. 1. of the accompanying drawings represents an end view of a dynamo
machine constructed according to my invention with one bearing removed so as to
show the commutator, brushes armature and field magnets.
Fig. 2. is a diagram of the method of winding the armature and connecting the
coils with the sections of the commutator.
In order to construct an efficient and practical dynamo for such low voltages as
one or two volts, instead of winding my armatures with coils connected each in
series with the next as is the case with armatures of the Gramme or Siemens type,
I wind the armatures of my improved low voltage dynamos with coils of wire or
.metal bars, and I connect the ends of each coil with a separate and distinct pair of
sections of the commutator, so that in a machine with two poles a section of the
commutator is connected with only one armature coil, instead of being connected
directly with two armature coils and through them with all the other armature coils
as in the Gramme ring or Siemens drum armature.
I collect the current generated in such coils as are passing the magnet poles and
therefore cutting lines of force, in parallel by means of a number of bruslies which
are placed at the active points instead of at the neutral points.
I thus construct a machine which has the voltage of one armature coil and gives
the sum of the currents of a number of armature coils.
In Fig. 1. N and S are the field magnets of a two pole dynamo, which are
constructed according to any well known design.
They are magnetised North and South either by means of shunt or series coils
or by coils separately excited by another dynamo.
A is the armature which may build up of a number of thin soft iron discs
insulated from one another and clamped and keyed on a spindle, like the well known
Siemens drum.
The commutator C is built up of say 32 sections insulated from one another in
the usual manner. They are clamped by means of a ring R screwed on to a bush D
fitted to the spindle H.
In order to allow air to circulate inside the commutator so as to keep it and the
armature cool make the bush D hollow and provide openings E. The commutator
sections may have slots communicating with the hollow chamber of the bush D, so
that the air may pass through them from the openings E, I sometimes place vanes

page_text: It the openings to proper air through the commutator slots when the armature is
rotating.
The armature is wound with coils of copper wire, ribbon or tape insulated with
cotton or otherwise.
Each coil makes one, two or more complete turns and has its ends connected with
opposite sections of the commutator.
:
Thus in Fig. 2. where A is the core of the armature and NN and S S are the
field magnets, F, is an armature coil and has its ends connected with the commutator
sections 1 and 17 which are opposite sections of the commutator.
Besides the coil F, the armature has fifteen other coils which are connected in a
similar manner with the remaining 30 commutator sections, but each coil and its
two commutator sections are insulated from all the others.
A number of brushes B, B, B,
and b b b . . of any well known type
are mounted in brush holders supported by a metal plate or bracket in any
convenient manner. The brushes are so adjusted that they make contact with those
sections of the commutator which are connected with those armature coils which
are cutting lines of magnetic force and have an electromotive force generated
in them.
The field magnets may embrace one half of the periphery of the armature so
that one half of the. armature coils are active and current may be collected from
them by the positive brushes B, B, B, and returned by the negative brushes
b₁ b₂ b3
სვ.
The current may be conducted from the brushes by one pair of leads or by
separate leads for each brush and may be passed through one tank or any number
of tanks connected in parallel or in series as desired.
The armature coils connected with the sections of the commutator not in contact
with the brushes are on open circuit and carry no current.
In an ordinary dynamo the brushes would have been adjusted to make contact
with the sections 8 and 24 or thereabouts.
When a higher electromotive force is desired the coil F in Fig. 2. may make two
or more turns round the armature.
As a rule the commutator has twice as many sections as there are coils on the
armature, in a two pole dynamo.
I may place a commutator at either end of the armature, each armature coil or
bar being connected with a section of each commutator and four sets of brushes
being provided.
I may construct machines according to my invention with four, six or any higher
even number of poles, and with a corresponding number of sets of brushes.
I may employ an armature built up according to my invention in the manner of
a Gramme ring, instead of a drum and I may vary the shape and arrangement of
field magnets and the number of the commutator sections, and brushes.
Instead of a number of brushes I may employ one metallic or other conducting
block on each side of the commutator.
The middle points of the armature coils being all at one potential may be
electrically connected if desired.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what
1 claim is :-
1. The combination in a dynamo electric machine of a number of open circuit
armature coils with sets of brushes arranged to collect the current from the active
coils substantially as described and illustrated.
2. Collecting the current from a number of coils of an armature in parallel.
3. Constructing an armature with a number of open circuit coils each of which
has its ends connected with distinct commutator sections.
4. The combination of a number of armature coils with twice that number of
commutator sections connected substantially as described.

page_text: 5. The armature and commutator substantially as described and illustrated in the
accompanying drawings.
6. The combination in a dynamo of any even number of magnet poles, with an
armature having a number of open circuit coils and brushes arranged to collect
current from active coils.
30
.
1001
J. A. KINGDON.