Improvements in Dynamo Electric Machines.
Year: 1890

page_text: Date of Application, 22nd Dec., 1890
Complete Specification Left, 22nd Sept., 1891-Accepted, 31st Oct., 1891
PROVISIONAL SPECIFICATION.
[Communicated from abroad by EDMOND LÉON DES ROZIERS, of 74, Rue Condorcet,
Paris, Engineer.]
Improvements in Dynamo Electric Machines.
I, HENRY HARINGTON LEIGH, Assoc. M. Inst. C.E., Fel. Inst. P.A., practising
as Phillips & Leigh at No. 22 Southampton Buildings, Chancery Lane, London,
Engineer and Patent Agent, do hereby declare the nature of this invention to be
as follows:-
In the ordinary dynamo each set of coils or magnets is connected with the
armature by a special conductor. It is therefore generally impracticable to move
the brushes.
According to the present invention each conductor is wound on a self induction
device with a magnetic circuit more or less, closed and a suitable resistance is
combined with the magnets. This resistance can be wound wholly or partially on
the said self induction apparatus in the same or opposite direction of the helices
or magnets. Therefore whatever may be the position of the brushes whenever a
set of coils is short circuited under the brushes the excess tension of current is
forthwith modified. Then when the set of coils comes out of short circuit the
potential energy of the circuit and of the self induction apparatus passes into the
circuit of the said helices and resistances.
Numerous modifications are practicable:
(a). A portion of the armature circuit may flow into the self induction device.
(b). The positions of the resistances may be varied.
(c). The resistances may be omitted.
(d). The self induction device may be a single crown or ring.
(e). Two Paccinotti crowns or rings may be used one acting as the armature of
the other for each circuit and may also be adjustable:
Dated this 22nd day of Dogambo 1000
HENRY H. LEIGH.
COMPLETE SPECIFICATION.
Improvements in Dynamo Electric Machines.
I, HENRY HARINGTON LEIGH; Fel. Inst. Ch. P.A., Assoc. M. Inst. C.E.
(practising as Phillips & Leigh) of No. 22, Southampton Buildings, Chancery
Lane, in the County of Middlesex, Engineer and Patent Agent, 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 dynamo electric machines, and its
object is to prevent the sparking which occurs between the commutator and the
brush of a dynamo electric machine so as to render it practicable to fix the brushes
in the different parts of a very wide zone of the commutator.
Sparking occurs when a section of one half of the induction armature is short
circuited under the brushes and enters into the other half.
This phenomenon depends upon the position of the brushes upon the commutator,
that is to say, upon the variation of the magnetic current cut by the section in
short circuit under the brushes, and also upon the received current.
The devices which are made use of to effect the purpose of this invention are
illustrated in the accompanying figures.

page_text: Fig. 1 is a. sectional elevation through the axis of the dynamo, illustrating the
application of the invention to an induction armature.
Fig. 2 is an elevation from the rear, i.e., looking at the dynamo from the side a.
(of Fig. 1.).
Fig. 3 illustrates one position of the parts of Fig. 2.
Figs. 4 and 5 illustrate different methods of winding, used in combination with
the construction illustrated in Figs. 1 and 2. -
All the figures relate to bi-polar armatures.
The construction of multipolar machines would be similar, and the following
explanations would also apply to them. The usual method has been in respect of
this class of dynamos to connect each section of the armature D directly to a plate
of the commutator C by a wire H (see Fig. 1). Under these conditions, the
position of the brushes is fixed beforehand for a given current if it is desired to
secure a proper run.
Each wire His wound upon a corresponding section of a Paccinotti or analogous
type of ring, P, fast upon the dynamo-shaft, before it is coupled to the corre-
sponding member of the commutator C. This ring may be built up of sheets or
plates held together in a suitable way. They are perdendicular to the axis of the
dynamo. A second ring A is arranged externally and concentrically to the said
ring P. It is composed of sheets or plates which are parallel to the plates of the
ring P. The ring A stands off a short distance from the Paccinotti ring and
provides the armatures of the primary magnetic circuits of the said ring.
The ring A is fixed upon or to a movable cylindrical support M screwed internally
and carried by a ring F, externally screwed, on the dynamo shaft. Thus when
the support M is turned, the ring A is moved about the ring P.
✓
So the primary magnetic circuits of the rings A and P are more or less quite
closed. At the moment when one section of the induction armature-becomes-short
circuited under the brushes, the current, which is inclined to acquire by the coils S
of the conductor H, a power increased according to the closure of the primary
magnetic circuits of the rings A. and P. With each position of the brushes
corresponds a suitable position of the ring A, that is to say, a suitable adjustment
of the ring A.if a strengthening of the current is desired.
The effect of this adjustment counterbalances, within certain limits, the differences
of variation of the magnetic flow cut by the sections getting short circuited under
_ the brushes.
These differences, it is well known, become accentuated-as-the-brushes-are-moved
from their normal position.
In like manner, the-more the ring A-is moved away from its normal position in
respect of the ring P, the more do the magnetic circuits of the rings A and P close,
and the action of the coils S increase. Consequently, the brushes B are connected
to the movable support M by a suitable mechanical connection which may be
varied as the special case may require.
Also the brushes may be fixed upon the moveable support M.
The angular displacement of the brushes B and of the support M are therefore
equal. The brushes may be fixed to the moveable support in such a way that their
angular displacement shall be proportional to that of the support.
Finally generally speaking, the brushes B may be connected to the moveable
support Min such a way that-the-angular-displacement-of-the-brushes_shall be
relative to that of the moveable support, as knowledge and experience may dictate,
or the peculiarities of the particular case may require. Fig. 1 is therefore left
indeterininate as to the mechanical connection between the brush B and the
support M. Under these conditions, it is clear that whatever may be the position
of the brushes with reference to the commutator, the current in the conductor H
and in the section in short circuit under the brush can be controlled as much as may
be required. To avoid sparking at the moment when the brushes cease to be on
one of the plates of the commutator, a resistance R (see Figs. 1 and 2) is placed
upon the coils S, and which resistance absorbs a large percentage of what may be

page_text: termed the sparking energy. The resistance R is placed in a suitable position after
the method indicated in Fig. 4.
The wire N of this resistance is wound in the
opposite direction to the coils S of the wire H upon the corresponding section of
the Paccinotti ring P. It may, however, be wound in the same direction as the
said coils S. The remainder of the resistance, R, that is to say, the portion, r, is
placed in resistance without practically effective self induction.
Fig. 5 illustrates another method of regulating. The current which is constantly
present in each half of the induction armature, also influences the elementary
sections of the Paccinotti ring, either in the same way as the coils S or the reverse.
For this purpose, in the different sections of the induction armature, the conductor
is disconnected from this armature and makes a few turns t upon one of the corre-
sponding or equivalent sections of the Paccinotti ring, P, then returns to the
induction armature.
If the wires t constitute a part of the induction armature which is short circuited
under the brushes, a definite result is obtained. If the said wires, t, do not constitute
a part of the induction armature which is short circuited under the brushes, a
different result is obtained.
In Fig. 3 the several primary circuits of the rings A and P are distinct. They
are separated from each other as shewn throughout the figure.
It has been assumed that the Paccinotti ring would be used in its usual cylin-
drical form with its projections normal to the shaft, and surrounded by a moveable
breech-plate or its equivalent. In point of fact, any Paccinotti ring may be used.
Speaking generally, any self induction magnetic system may be used. They will
be varied according to the position of the brushes with regard to their normal
position, and will be excited by various kinds of coils such as S, N, and t.
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 I
claim is :
1. In dynamo machines, self induction devices each having variable magnetic
circuits by the relative displacement of a part of the said magnetic circuit, such dis-
placement being in mechanical connection with that of the brushes, each one of these
self induction devices being surrounded a certain number of times by a conductor
connecting a section of the induction armature to the corresponding part of the
collector in such a way that the momentary current flowing through the said
conductor shall act upon the said self induction device or devices for the purpose
of modifying them.
+
2. In dynamo machines, self induction devices having magnetic circuits variable
by the relative displacement of a part of the magnetic circuits, this displacement
being independent of that of the brushes each self induction device having wound
round it a certain number of times a wire connecting a section of the induction
armature with the corresponding plates of the collector in such a way that the
momentary current which flows along the said conductor shall act upon the said
self induction device by way of modifying it.
3. In dynamo machines, self induction attachment devices excited each one by a
conductor which connects a section of the induction armature to the corresponding
plate of the collector, and having a derived circuit from a resistance as specified.
4. In dynamo machines, with self induction attachment devices each one actuated
by a conductor which connects a section of the induction armature to the corre-
sponding plates of the collector, and provided with an electrical attachment
consisting of a resistance wound to some extent about or upon the said self induction
devices so as to excite them at suitable moments.
5. In dynamo machines devices with self induction attachments each one actuated
by a conductor which connects a section of the induction armature to the corre-
sponding plates of the collector and acted upon at the same time by the coils of a
conductor constituting a part of a section of the induction armature and through
which coils the armature current flows.

page_text: 6. In dynamo machines, devices with self-induction attachments each one by a
conductor which connects a section of the induction armature to the corresponding
plates of the collector in such a way that the influence of the conductor upon the
self induction device shall be combined with that of a resistance and that of a coil
which is a part of the induction armature as set forth in Claims 3, 4 and 5.
Dated this 22nd day of September 1891.
HENRY H. LEIGH,
Chartered Patent Agent.