Appliance for Equalising the Loads of the several Conductors of Rotary Phase Current Installations.
Year: 1892

page_text: Date of Application, 7th Jan., 1892
Complete Specification Left, 4th Oct., 1892-Accepted, 5th Nov., 1892
PROVISIONAL SPECIFICATION.
[Communicated from abroad by Messrs. SIEMENS & HALSKE, 94, Markgrafen-
strasse, Berlin, in the German Empire, Electrical Engineers.]
Appliance for Equalising the Loads of the several Conductors of
Rotary Phase Current Installations.
We, SIEMENS BROTHERS & CO. LIMITED, of 12 Queen Anne's Gate, West-
minster, in the County of Middlesex, Electrical Engineers, do hereby declare the
nature of this invention to be as follows:-
If it is required to supply a number of current consumers at one or more localities
by means of rotary phase currents, which consumers partly use all the conductors
carrying the said currents, and partly only use some of them; or, in other words,
if motors and lamps require to be worked simultaneously, the difficulty arises, that
either at least three lamps must always be put in or out of action, or one has to
put up with the comparative indifferent degree of action which results when a
motor is worked by unequally loaded rotary phase current conductors.
The present invention consists in an arrangement whereby the load of the
several rotary phase current conductors is maintained nearly constant, independently
(between certain limits) of any variation in the number of lamps in action supplied
thereby. Rotary phase currents have, as is well known, the property that the
sum of all the currents in the circuit operating at any moment is equal to zero.
Consequently if an iron core is surrounded by as many windings as there are
rotary phase conductors, and if each of the said windings be introduced between a
pair of rotary phase current conductors the magnetisation of the core will be at
every moment equal to zero, so long as the rotary phase current carried by the
conductors is norinal, that is to say, so long as the amplitudes of all the alternating
currents that form the rotary phase current are equal, and so long as all such
alternating currents are shifted relatively to each other to an equal extent, as
regards their phase. But as soon as changes take place either as regards the
amplitudes or as regards the shifting of the phases, between a pair of rotary
phase current conductors, or between several pairs thereof, the said iron core will
be magnetised and will produce, in a similar manner to transformers, secondary
electro magnetic forces in the other windings which are added to the primary
electro magnetic forces already existing therein.
In consequence of the secondary electro-magnetic forces thus produced, any
alteration in the load of one or more branches of the rotary phase current system
will necessarily produce alterations in the load in all the other branches thereof,
and the said secondary electro magnetic forces will be of such a nature that there
will always be a tendency to restore the original condition of the normal rotary
phase current, namely equal amplitudes, and equal shifting of the phases.
The above described arrangement, which may be appropriately termed an
"equalizer" can be carried out in a variety of ways. Thus according to one
arrangement with three rotary phase current conductors, in which the lamps are
arranged in parallel, the three windings of the equalizer are also arranged in
parallel and are made to constitute a continuous winding upon a ring of iron, to
which winding leads connecting the same with the three conductors, are connected
at equidistaut points. Within the iron ring is placed an iron core.
According to another modification of this arrangement the lamps are placed in
series in the rotary phase current conductors, as are also the three windings of the
iran ring of the equalizer

page_text: According to another arrangement, the three windings of the equalizer are
placed upon separate parallel straight iron cores that are connected together by
iron rings at their ends. With this construction also the connections may either
be in parallel or in series.
ABEL & IMRAY,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Appliance for Equalising the Loads of the several Conductors of
Rotary Phase Current Installations.
We, SIEMENS BROTHERS & Co. LIMITED, of 12, Queen Anne's Gate, West-
minster in the County of Middlesex, Electrical Engineers, 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 :-
If it is required to supply a number of current consumers at one or more
localities by means of rotary phase currents, which consumers partly use all the
conductors carrying the said currents, and partly only use some of them; or, in
other words, if motors and lamps require to be worked simultaneously, the
difficulty arises, that either at least three lamps must always be put in or cut of
action, or one has to put up with the comparative indifferent degree of action
which results when a motor is worked by unequally loaded rotary phase current
conductors.
The present invention consists in an arrangement whereby the load of the
several rotary phase current conductors is maintained nearly constant, independently
(between certain limits) of any variation in the number of lamps in action supplied
thereby. Rotary phase currents have, as is well known, the property that the
sum of all the currents in the circuit operating at any moment is equal to zero.
Consequently if an iron core is surrounded by as many windings as there are
rotary phase conductors, and if each of the said windings be introduced between
a pair of rotary phase current conductors the magnetisation of the core will be
at every moment equal to zero, so long as the rotary phase current carried by the
conductors is normal, that is to say, so long as the amplitudes of all the alternating
currents that form the rotary phase current are equal, and so long as all such
alternating currents are shifted relatively to each other to an equal extent, as
regards their phase. But as soon as changes take place either as regards
the amplitudes or as regards the shifting of the phases, between a pair of
rotary phase current conductors, or between several pairs thereof, the said iron
core will be magnetised and will produce, in a similar manner to transformers,
secondary electromagnetic forces in the other windings which are added to the
primary electro-magnetic forces already existing therein.
In consequence of the secondary electromagnetic forces thus produced, any
alteration in the load of one or more branches of the rotary phase current system
will necessarily produce alterations in the load in all the other branches thereof
and the said secondary electro-magnetic forces will be of such a nature that there
will always be a tendency to restore the original condition of the normal rotary
phase current, namely equal amplitudes, and equal shifting of the phases.
The above described arrangement, which may be appropriately termed an
equaliser can be carried out in a variety of ways. Taking for example, the case
of three rotary phase current conductors, each supplying a service consisting of
one or a number of lamps or other current consumers, the required equalisation is
effected according to our invention as shewn diagrammatically by Fig. 1. Each
of the three conductors A' A' A' divides into two branches, the one branch in
each case going as entering wire to supply one of the services B¹ B' B³, the other

page_text: branch in each case going as entering wire to one of three equal coils C¹ C³
wound on an iron ring R. The leaving wires of all the coils C' C² C³ are
connected together to a point D where the leaving wires of all the services B¹ B'B'
meet.
The coils of the equaliser, instead of being wound on a closed ring R, as shewn
in Fig. 1, may be wound, as shewn in Fig. 2, upon parallel cores connecting a pair
of rings or they might be wound on the cores of transformers of other known
forms. When there are more than three conductors, there is a corresponding
number of coils on the equaliser connected in a similar way to the several
services.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we would have it understood
that we make no general claim to the construction of equalisers such as are
hereinbefore referred to, but what we claim is :-
In combination with three or more couductors of rotary phase currents supplying
services of lamps or other consumers of electricity, an equaliser arranged as
a closed magnet transformer with as many coils as there are conductors, each of
the coils having its entering wire connected to one of the conductors at a point
whence it branches to enter its service, and all the coils having their leaving wires
connected together to the leaving wires of all the services, substantially as and for
the purpose herein set forth.
Dated this 4th dow of October 1802