Improvements in the Regulation of Dynamo-electric Machines and other Electrical Apparatus.
Year: 1893

page_text: Date of Application, 28th Nov., 1893-Accepted, 14th Apr., 1894
COMPLETE SPECIFICATION.
[Communicated from abroad by THE THOMSON HOUSTON INTERNATIONAL
ELECTRIC COMPANY, of 620, Atlantic Avenue, Boston, Massachusetts,
. United States of America.]
Improvements in the Regulation of Dynamo-electric Machines and
other Electrical Apparatus.
1, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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 :—
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The present invention relates to an improvement in that class of dynamo
electric machines whether generators or motors which are compound wound, and
which consequently have a portion of their field magnetism furnished by a shunt
across the mains, or by a separate exciter kept at a fairly constant potential, while
the remaining portion of their field magnetism is due to the main current passing
through the second set of field coils, generally known as "series" coils and is
designed to adapt such machines to the conditions incident to their working in
multiple arc, and at the same time to provide for the relative adjustment of the
magnetic effects due to the series coils of the different machines, so that each one
may be kept at such potential as to take its proper proportion of the load. The
adjustment of the series field is also made for the purpose of adapting the electro-
motive force of the machines to variations in drop of potential, so that under light
load they may give a certain potential, and under heavy loads may increase the
potential by what is known as over-compounding" or compounding for increase of
potential at the terminals, or for constant potential at a distant point. Two or
inore such machines when running in multiple arc and feeding the same system of
mains, should be provided for stability of action, with an "equalizing connection
between those points in their circuits at which their series field terminals are
connected to the commutator brushes. With machines thus working in multiple
are and connected by an equalizer their series field coils are practically in multiple
arc, and if a shunt be thrown around one of them, such a shunt will act equally to
divert current from all the other field coils connected in the system. It does not,
in other words, individualize its shunting effect to the particular machine for which
it is intended. Evidently then, no proper adjustment of the relation to each other
of the series windings of the different machines can be obtained under the condition
mentioned. To avoid this difficulty is the aim of the present invention. The series
turns of such machines as are running in multiple arc are divided into two or more
sections, part of which are always in the main circuit and are not varied by
shunting, while around the remainder a variable shunt is provided, whereby in each
machine the total influence of the different sections of the series coil may be varied
by a proper variation of one such section. It is evident that in this way an
individual adjustment may be obtained which, while not absolute, may be made
approximately correct, and the proper balance of work between the machines
may be preserved by adjusting the relative effects of their series windings.
In the accompanying drawings illustrating the invention,
Fig. 1 shows a dynamo electric machine wound after the present invention.
Fig. 2 shows diagrammatically two machines similarly wound, and coupled up so
as to work in multiple are on a common circuit;
macking by itself similarly constructed.

page_text: Fig. 4 shows three machines operating according to the invention, and
Fig. 5 shows an improved means of carrying out its application.
The machine shown in Fig. 1 has four poles which are energized by shunt or
separate exciting coils S, and in addition by coils D D, E E, through which the
main current passes, and which are the series coils for compounding.
Variable
resistances R R are put in shunt around the coils E E, while the coils D D are
left unshunted and traversed by the main current in toto. Of course however,
these coils may be shunted by a permanent shunt at any time when the number of
ampere turns in D D. becomes too great for the existing condition of the circuit.
Referring now to Fig. 2, two armatures A', A² are shown with shunt field
magnet coils S', S', which, as before stated, may be replaced by separate exciting
coils furnishing an initial field. In series with the armatures are heavy series coils
divided into sections D', E' for the one machine, and D2, E' for the other. The
sections D', D are connected directly to the main M, and are never shunted.
Around the sections E', E' respectively are variable resistance shunts R', R2
whereby such sections may be more or less completely shunted and the desired
adjustment of the machines individually and relatively to one another be effected.
The equalizing connection is shown at Q. The variable resistances may be of any
desired type. They may in fact be shunts of definite value connected across the
sections E, E, such as strips of German silver shunting from 5 to 15 or 20% of
the current, one strip being removed and replaced by another as becomes necessary
to give the desired effect. In Fig. 3 a single machine A is shown diagrammatically
which has its field excited by a shunt coil Ŝ and a series coil divided into sections D
and E. The section E is shunted by a variable resistance R, and renders the effect
of the series coil variable.
The operation of the invention will be understood from the foregoing. Evidently
if the shunting resistance spanned the entire series coil it would not only divert the
current from the coil of that particular machine, but also would shunt substantially
the same amount of current around the corresponding coils of such other machines as
might be running in multiple therewith, for the resistance of the equalizing
connection is very low. The, field of each machine would therefore be corre-
spondingly affected. When only a portion of the series coil is shunted, as herein
described, the relative effect of the series coils upon the different machines may be
regulated, for any influence which a change of resistance R₁ or R² has upon a
companion machine is comparatively small, and may be rendered unimportant.
This invention is especially important when using machines in which the
characteristic curve, or curve of compounding, is different for the different
machines. In such case the machines might run together perfectly at half load
but at full load one machine would be found to be carrying more than its due share
of current. This condition of affairs should be rectified by lowering the potential
of that machine which is doing the greater part of the work, and this may be done
by simply adjusting the series field strength accordingly.
In Fig. 4, D, D' and D³ represent three compound wound electric generators
whose shunt field coils are indicated at S, S₁ and S2 and whose series coils or
compounding coils are represented at B, B' and B2 respectively. Rheostats R, R, R,
in the shunt field circuits permit the regulation of current flow therein as usual.
In series with each of the coils B, B and B are rheostats R', R', R. In shunt
relation to the coils B, B1, B2, or in shunt relation to a portion of such coils, are
other rheostats R, R2, R2, respectively. In a derived circuit around the coils B, B¹
and B is a circuit ed including a rheostat R³. One pole of each machine connects
to the omnibus wire O. The other pole of each machine connects to the omnibus
wire O2 through the series field coils. An equalizing connection O' connects all of
the series field coils in multiple. Assuming that the machines D and D' were
properly compounded with the apparatus in position shown, and the machine D'
required more current in its series field coils B' to properly compound it, if the
resistance R' were diminished it would be found that the current would be diverted
from the series field coils B and B of the machine D and D', which current would

page_text: flow through the coil B' to omnibus wire O' by way of the equalizing connection O¹.
It would therefore be necessary to adjust the rheostats R' of the machines D and D'
every time the rheostat R' of the machine D was changed, and in fact the operator :
would be required to make a large number of adjustments of the rheostats R
passing from one machine to another to balance the compounding accurately. It
is evident that the necessity for such a large number of adjustments has been
occasioned by changing the resistance of the circuit B', R' of the machine D', and
that if the amount of current flowing through the coil B' could be varied without
changing the resistance from 01 to 0³, no such difficulty of adjustment as has been
mentioned would be experienced. This result is in fact accomplished by using an
accessory resistance R placed in shunt around, the series coil B', B³ or in shunt
around a portion of such series coil, as around coil B.
Now, if when the resistance R' has been diminished, the resistance R³ is increased
to a like extent, then the resistance between the equalizing connection O' and O³
will have been unchanged, but it is evident that the current flowing through the
coil B will have been altered. In the same manner, suppose it were required to
decrease the compounding current flowing through the coil B of the machine D,
then the resistance R' in shunt around a portion of the coil B would be diminished,
and the current would be diverted through R. But this would result in a decrease
of resistance between O' and O' which would disturb the proper compounding of
the machines D and D' by diverting current therefrom. This effect is prevented
by increasing the resistance R¹ of the machine D just as much as R had been
diminished, and by this means the compounding effect of the series coil B may be
increased or diminished, while the effect on the machines D1 and D2 is nil. To
afford a quick adjustment of all the machines D, D' and D', to a like extent, a
rheostat R is provided with a circuit c, d, connecting O' and 0%. In case of a
very heavy load or short circuit existing on the external circuit connected to the
point a b, the attendant would increase the resistance R³, diverting current from all
the coils B, B' and B' to prevent an over-compounding action.
This invention also relates to an apparatus for adjusting the current passing
through a coil without altering the amount of resistance in circuit in carrying out
the method described.
In Fig. 5 of the drawing D, D' and D³ represents three dynamo electric machines
or generators connected in multiple between the omuibus wires 0, 02, from which
lead the external circuit wires ab going to the work, represented here by electric.
railway motors C and C¹. S, S¹ and S are the shunt field magnet coils of the"
machines D, D' D³, respectively, connected in derivation to the brushes on the
machines and included in whose circuit may be placed rheostats N, N, N, for
regulation. B, B1 and B' are the series coils of the machines D, D' and D'
conveying the main current to the circuit a, b. O₁ is an equalizing conductor,
connected in the circuit in the usual manner.
A resistance R', R³, R' is placed in shunt around a portion of the series coil of
cach machine, as shown at R¹ in the machine on the left hand side of the drawing,
which resistance R¹ shunts a portion of the series coil at e, f. Such resistance Ri
is used in conjunction with a resistance R, which latter is in series with the coil B,
as shown. It is evident that the resistances R and R' may be simultaneously
varied, so that while R is increasing in amount R' would be diminishing, or vice
versa; and while the total resistance between 0 and O¹ remains unchanged, the
amount of current flowing through the series coil B would be changed by the
diversion of current through R'. The compounding action of the coil B of
the machine D may be in this manner increased or diminished without affecting the
compounding action of the other machines D' and D. The machines D' and D'
would of course be provided with regulating appliances similar to those described.
While the resistances R and R' may be adjusted separately, it is preferred to
make their action interdependent and automatic, and any arrangement for accom-
plishing this will answer the purposes of this invention. Any suitable arrangement,
mechanical or electrical, may be employed to obtain this interdependent action,

page_text: whereby any movement of the rheostat arm operating to change the resistance of R
would cause a compensating change in the resistance R' or vice versa, and in such a
manner as to maintain the resistance between O and O¹ practically constant.
In the figure, the arms A, A' of the rheostats R and R' are shown adapted to
be operated by a single handle H. These arms are independently pivoted at the
point P, the arm A moving with the handle H, while the arm A is disconnected
therefrom. A slotted yoke Y is secured to the arms A A' by thumb-screws X, X¹
clamping the arms thereto and cause them to move simultaneously with the
operation of the handle H. When the machine D is placed in position in multiple
with the other machines, the arms A and A¹ are independently adjusted to give the
proper balance to the resistances R and R' in accordance with the drop of potential
in the omnibus wires, and cther conditions: the position of compensation being
ascertained, the thumb-screws X and X' are tightened, and thereafter any
regulation of the current through the series coil B of the machine D will not affect
the compounding action of the other machines in multiple therewith, the total
resistance between O' and O' remaining unchanged as described.
It is manifest that the method herein set out may be applied to the regulation of
coils other than those of a dynamo electric machine, where such regulation is
desirable.
Having now particularly described and ascertained the nature of this said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
1. The combination of two or more compound wound dynamo electric machines
working in multiple are and connected by an equalizer, with means for adjusting
individually, and with relation to one another the field strength of the different
machines due to their respective windings, as set forth.
2. The combination of two or more compound wound dynamo electric machines
working in multiple are and connected by an equalizer, with means for shunting
portions of the series windings of such machines individually, and thereby altering
the relation between their respective series fields, as required.
3. The combination of two or more compound wound dynamo electric machines
working in multiple arc and connected by an equalizer, and having their series
windings divided respectively into sections, part of which are always in the main
circuit of the machine, and another part of which are shunted by shunt connections
of variable resistance.
4. A compound wound dynamo electric machine having its series winding divided
into sections, and a shunt connection of variable resistance around a part only of
such series winding, as set forth.
5. The method of adjusting an electric coil, which consists in varying the
compounding effect of the coil while maintaining a constant resistance between its
terminals.
6. The method herein set out, of adjusting compound dynamo electric machines,
which consists in maintaining a substantially constant resistance in circuit with the
series coil between the brush and line, while varying the current passing through
the series coil.
7. The method of individually regulating the compounding effect of the series
coils of a number of dynamo electric generators feeding in the same work circuit
in multiple, and connected as described, consisting in separately varying the
current flowing through said series coils without changing the resistance between
the omnibus wire and the equalizing connection, substantially as described.
8. The method of individually regulating the compounding effect of one of the
series coils of a number of dynamo electric generators feeding the same work
circuit in multiple, which consists in inversely varying two resistances, one in
series with said series coil and the other in shunt thereto, substantially as set
forth.
9. The method of regulating a group of compound-wound electric generators

page_text: feeding the same work circuit in multiple, consisting in simultaneously varying the
current flowing through the series coils of said generators by changing the
resistance of an alternative or derived circuit around all of said coils, substantially
as described.
10. The method of regulating a plurality of compound-wound electric generators
connected in multiple to the work circuit, consisting in separately varying the
current flowing through the series field coils of said generators, without changing
the total resistance between the terminals of said coils, and then varying the
current flowing through all of said coils simultaneously, by changing the resistance
of an alternative or derived circuit around said coils, in correspondence with the
conditions of load, substantially as set forth.
11. The combination with a number of dynamo electric generators feeding the
same work circuit in multiple, of one or more rheostats each one in series to the
series coil of one of said generators, substantially as described.
12. The combination with a number of dynamo electric generators feeding the
same work circuit in multiple, of two rheostats for each generator, one in series
with its series coil and the other in shunt thereto, substantially as set forth.
13. An apparatus for adjusting the current passing in an electric coil without
varying the resistance thereof, which consists of a resistance in series with the coil,
a second resistance in shunt to a portion thereof, and means, substantially as
described, for simultaneously and inversely varying the two resistances.
14. A compound wound dynamo having a series coil and an adjustable resistance
in series therewith, a second adjustable resistance in shunt around a section of the
coil, and means adapted to vary the resistances simultaneously and inversely,
whereby the resistance between the brush and the line is maintained substantially
constant, while the total current passing in the coil may be varied.
15. A plurality of dynamo electric machines having series coils connected in
multiple between an omnibus wire and the brushes and an equalizing conductor
between them, each machine provided with a resistance in series with the series
coil, a second resistance in shunt around a part thereof, and means adapted to vary
the resistances simultaneously and inversely; whereby the total resistance in each
circuit is constant while its distribution may be altered to vary the current in the
coil, thus permitting the adjustment of one machine without disturbing the others.
16. An apparatus for varying the current passing in an electric coil without
changing the resistance thereof, which consists of a resistance in series with the
coil, a second resistance in shunt to a part thereof, a pair of contact arms adjustable
towards or away from each other and connected to a common actuator adapted to
move them simultaneously and inversely and thus cut out a part of one resistance
and cut in a similar part of the other resistance.
Dated this 20th dow of Naomben 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.