Improvements in the Regulation of Electric Currents.
Year: 1889

page_text: Date of Application, 14th Mar., 1889
Complete Specification Left, 14th Jan., 1890-Accepted, 14th Apr.,
1890
PROVISIONAL SPECIFICATION.
Improvements in the Regulation of Electric Currents.
I, WILLIAM MORRIS MORDEY, of Victoria Works, Belvedere Road, Lambeth, in
the County of Surrey, Electrician, do hereby declare the nature of this invention to
be as follows :-
The object of this invention is to provide means for maintaining a constant potential
difference at the lamps or other utilisation devices on alternate current parallel
systems.
The method of working which offers the greatest advantages.and which is most
oxtensively employed, is what is known as the constant potential parallel system in
which the primary circuit has a much higher tension than the secondary circuit or
circuits and in which the potential difference at the transformers or at some point on
the mains is sought to be maintained constant. This invention applies equally
whether the object is to transform up or down, or to the direct use of alternate
ourrents without transformers.
In this system as employed with transformers, there are certain losses which cause
a variation in the light of the lamps, even when the primary mains are maintained at
a constant potential. These losses are in the transformers and in the conductors both
primary and secondary, and the effect on the lamps is such that when a small number
of lamps is in circuit the light of each lamp is greater than when a large number is in
circuit.
The object of this invention is to overcome this defect. It will be seen that no
system of automatic or other regulation of the dynamo or of the primary circuit as a
whole can possibly compensate for the variations in the individual transformers and
secondary circuits; inasmuch as even if the primary potential difference at any point
or points is kept constant, or is adjusted to allow for any given load, it will not
equally and suitably affect all the transformers, some of which may be lightly loaded,
while others are doing their full work. The present means of regulation, however,
acts in each individual case according to the requirements of the case.
In addition to the transformers I use a small apparatus which I call a corrector,
resembling a transformer in construction, and consisting of a suitably laminated iron
core or sheath provided usually with two coils of wire, and I usually avail myself of
the property of magnetic saturation possessed by the iron. I may carry out this
invention in several ways, one of which is as follows:-
The corrector is wound with two windings, one of comparatively fine wire, which is
connected as a shunt to the secondary terminals of the transformer and thus is in
parallel with the lamps. The other coil is of a thicker conductor and has a smaller
number of turns, and is connected in series with the lamps, that is to say, it is
connected between one of the secondary terminals of the transformer and one of the
secondary mains, the other secondary main being connected directly to the other
secondary terminal of the transformer. The shunt winding may be connected across
the secondary and the series winding combined, that is across the lamp terminals,
instead of to the secondary terminals. The two circuits of the corrector are arranged
to be traversed by currents in the same direction. The shunt or fine wire winding,
of the corrector, which I call the initial winding, is designed so that when connected
to the transformer alone, it receives such a current that the iron receives a certain
initial magnetisation. In this condition the corrector opposes a certain impedance,
opposing E.M.F., or choking action to any small current through its series winding,
the effect, when a small number of lamps is switched on, being to reduce the potential
difference available in the secondary circuit, to a value somewhat below that existing
at the secondary terminals of the transformer. On the passage of a larger current iq

page_text: the secondary circuit, as when more lamps are switched on, the opposing E.M.F. or
choking action of the corrector becomes reduced on account of the saturation of the
iron and a larger potential difference is made available in the secondary circuit. This
effect is produced with only a trifling expenditure of energy, and the corrector is not
to be taken as equivalent in this respect to a resistance.
In order to prevent any considerable current traversing the shunt winding of the
corrector when saturation is reached or nearly approached, I may insert in series
with that winding, a small impedance coil working at a low magnetic density, or a
resistance, but preferably the former. Or I may place the initial coil of the corrector as a
shunt on the primary terminals of the transformer, the other winding of the corrector
being in series with the secondary circuit as before. With this last mentioned
arrangement I may place a non-saturation impedance coil, or a resistance, in series
with the initial coil of the corrector and between this coil and the primary terminals of
the transformer, for the purpose of preventing an excessive current traversing the
initial coil when saturation is reached or nearly attained.
Or the initial coil of the corrector may be connected to the secondary terminals of
the transformer, either direct or through a non-saturation impedance coil, the second
coil of the corrector being placed in series with the primary of the transformer.
According to another arrangement I place the initial winding of the corrector in
series with the primary coil of the transformer, and so design it that the iron of the
corrector is brought up to the required initial magnetic density by the open circuit
current of the transformer (that is, the current which traverses the primary when
the secondary is on open circuit), and I connect the other coil of the corrector as
before, in series with the secondary circuit.
Or I may dispense with a second winding on the corrector, placing. its single
winding in series with the primary of the transformer, the socondary of which may
be joined direct to the secondary circuit.
Or I may use a single coil on the corrector placing it in series with the secondary
of the transformers and so proportioned that the sinallest current required (e.g. that
necessary for one lamp) will provide the necessary initial magnetisation.
By suitably proportioning the corrector any required correction may be obtained.
Thus the available E.M.F. impressed upon the secondary circuit may be kept constant
or may be made to rise slightly, in order to compensate for any loss in the conductors,
and an effect produced on individual parts of a distribution system such as, in
continuous current working is obtained by "compounding" a dynamo, except that in
the latter case the effect is only capable of acting on a circuit as a whole, and not
as in this case soparately on its individual branches. It will be understood that this
device acts in such a way as to compensate for losses in any part of the circuit,
acting in one direction on the secondary circuit, and in the other on the trans-
former, on the primary mains, and on the dynamo. One very useful result attained
by the invention is, to enable conductors to be used of a size less than would
otherwise be necessary to maintain the required degree of constancy of potential, as,
for instance; where considerable distances have to be traversed by either the primary
or the secondary circuits.
This invention may be sometimes applied to a portion only of a secondary circuit.
Thus where one branch is of greater length than another, as when a transformer hns
to supply lamps in its immediate vicinity as well as other lamps at a distance, I may
connect only the longer circuit to the corrector. Similarly when a number of
circuits radiate from one point, whether it be a dynamo or transformer supplying
lamps or other devices, or a transformer arranged at a centro and transforming down
or up to other primary circuits (as in distribution at a very high tension) I employ
a separate corrector for each circuit, suited to the requirements of such circuit.
Dated this 14th dow of Mauch 1000

page_text: COMPLETE SPECIFICATION.
Improvements in the Regulation of Electric Currents.
I, WILLIAM MORRIS MORDEY, of Victoria Works, Belvedere Road, Lambeth, in
the County of Surrey, Electrician, 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 :-
The object of this invention is to provide means for maintaining a constant
potential difference at the lamps or other utilisation devices on alternate current
parallel systems.
The method of working which offers the greatest advantages and which is most
extensively employed, is what is known as the constant potential parallel system in
which the primary circuit has a much higher tension than the secondary circuit or
circuits and in which the potential difference at the transformers or at some point on
the mains is sought to be maintained constant. But this invention applies equally
whether the object is to transform up or down, or is to the direct use of alternate
currents without transformers.
The term constant-potential parallel systems is to be taken as including what are
known as the multiplo series modifications of that system.
Although for simplicity of description the following explanation refers principally
to the use of transformers, it is to be understood that similar results are obtained
when the invention is applied to the direct use of alternate currents.
In this
latter case the alternate current generator is the apparatus directly acted on.
This
arrangement may be used whether the circuit has transformers or not.
In the alternate current system as employed with transformers, there are certain
losses which cause a variation in the light of the lamps, even when the primary
mains are maintained at a constant potential. These losses are in the transformers
and in the conductors both primary and secondary, and the effect on the lamps is
such that when a small number of lamps is in circuit the light of each lamp is
greater than when a large number is in circuit.
The object of this invention is to overcome this defect. It will be seen that no
ordinary system of automatic or other regulation of the dynamo or of the primary
circuit as a whole can possibly compensate for variations in the individual trans-
formers and secondary circuits; inasmuch as even if the primary potential difference
at any point or points is kopt constant, or is adjusted to allow for any given load,
it will not equally and suitably affect all the transformers, some of which may be
lightly loaded, while others are doing their full work. According to this invention,
however, the means of regulation employed, act in each individual case according to
the requirements of the case.
In addition to the transformers I use a small apparatus which I call a corrector,
resembling a transformer in construction, and consisting of a suitably laminated
iron core or sheath provided usually with two coils of wire, and I avail myself of the
property of magnetic saturation possessed by the iron. I may carry out this
invention in several ways, one of which is as follows:-
:-
The corrector is wound with two windings, one of comparatively fine wire, which
is connected as a shunt to the secondary terminals of the transformer, and thus is
in parallel with the lamps. The other coil is usually of a thicker conductor and has
a smaller number of turns, and is connected in series with the lamps, that is to
say, it is connected between one of the secondary terminals of the transformer and
one of the secondary mains, the other secondary main being connected directly to
the other secondary terminal of the transformer. The shunt winding may be
connected across the secondary and the series winding combined, that is across the
lamp terminals, instead of to the secondary terminals. The two circuits of the
corrector are arranged to be traversed by currents in the same direction. The shunt
or fine wire winding, of the corrector, which I call the initial winding, is designed
so that when connected to the transformer alone-that is when no lamps or other

page_text: apparatus are in use-it receives such a current that the iron attains a certain high
initial magnetisation. In this condition the corrector would set up a certain impedance,
opposing E.M.F., or choking action to any small current through its series winding,
the effect, when a small number of lamps is switched on, being to reduce the potential
difference available in the external secondary circuit, to a value somewhat below that
existing at the secondary terminals of the transformer. On the passage of a larger
current in the secondary circuit, as when more lamps are switched on, the opposing
E.M.F. or choking action of the corrector becomes reduced on account of the greater
degree of saturation of the iron and a larger potential difference is thus made available
in the secondary circuit.
In order to prevent any considerable current traversing the shunt or initial winding
of the corrector when saturation is reached or nearly approached I prefer to insert in
series with that winding, a small impedance coil which may be arranged to work at
a low magnetic density, or a resistance or both arranged with due regard to any lag
or difference of phase which may exist, or tend to exist, between the initial and main
currents, so as to assist to give the desired effect. The amount of this inductional
resistance so required depends to some extent upon the character of the secondary
or other circuit which it is proposed to supply and upon the amount of correction
required. By varying it to suit each case the same construction of corrector may be
used on circuits requiring different amounts of correction.
The accompanying drawing shews this arrangement diagrammatically.
T is a transformer the secondary circuit of which it is desired to regulate. P is the
primary winding, S the secondary winding, C is the corrector wound with an initial
winding and a correcting winding c. L, L are the lamps or other utilisation devices
arranged on the secondary circuit. In series with tho initial winding i is a resistance
or inductional resistance R.
It will now be understood how the principle underlying this invention is applied,
this principle consisting in providing a back electromotive force, whose opposing action
diminishes with the increase of the current sent through it. The regulating effect is
produced with only a small expenditure of energy, the corrector acting in this respect
as an opposing E.M.F. and not as an actual resistance.
The above described way of carrying out this invention is a useful one for ordinary
purposes, hut other ways, which are modifications of the above, will present themselves
which will suffice for some purposes, although I consider them loss advantageous than
that above described. For instance, I may place the initial coil of the corrector as a
shunt on the primary terminals of the transformer, the other winding of the corrector
being in series with the secondary circuit as before. With this last mentioned
arrangement I may place a non-saturation impedance coil, or a resistance as above
described in series with the initial coil of the corrector and between this coil and the
primary terminals of the transformer, for the purposes already mentioned.
Or the initial coil of the corrector may be connected to the secondary terminals of
the transformer, either direct, but preferably through a non-saturation impedance coil
or resistance or both, the second coil of the corrector being placed in series with the
primary of the transformer.
According to another arrangement I may place the initial winding of the corrector
in series with the primary coil of the transformer, and so design it that the iron of the
corrector is brought up to the required initial magnetic density by the open circuit
current of the transformer (that is, the current which traverses the primary when the
secondary is on open circuit), and I connect the other coil of the corrector as before,
in series with the secondary circuit.
Or 1 may dispense with a second winding on the corrector, placing its single
winding in series with the primary of the transformer, the secondary of which may be
joined direct to the secondary circuit.
Or 1 may use a single coil on the corrector placing it in series with the secondary
of the transformer and so proportioned that the smallest current required (e.g. that
necessary for one lamp) will provide the necessary initial magnetisation.
By suitably proportioning the corrector any required. correction may be obtained.

page_text: Thus the available E.M.F. impressed upon the secondary circuit may be kept constant
or may be made to rise slightly, in order to compensate for any loss in the conductors,
and an effect produced on individual parts of a distribution system such as in direct
current working is obtained by what is known as "Compounding "a dynamo, except
that in the latter case the effect is only capable of acting on a circuit as a whole, and
not as in this case separately on its individual branches. It will be understood that
the regulating device constituting this invention acts in such a way as to compensate
for losses in any part of the circuit, acting in one direction on the secondary circuit,
and in the other on the transformer, on the primary mains, and on the dynamo. One
very useful result attained by the invention, is to enable conductors to be used of
a size less than would otherwise be necessary to maintain the required degree of
constancy of potential, as for instance where considerable distances have to be traversed
by either the primary or the secondary circuits.
This invention may be sometimes applied to a portion only of a secondary circuit.
Thus where one branch is of greater length than another, as when a transformer has to
supply lamps in its immediate vicinity as well as other lamps at a distance, I may connect
only the longer circuit to the corrector. Similarly, when a number of circuits radiate
from one point, as in the case of a large transformer, or transformer battery placed at
a distribution centre and transforming up or down to those circuits, I may employ a
separate corrector for each circuit suited to the requirements of such circuit.
Thus I am enabled to supply circuits of different lengths or resistances and by
using one and the same potential difference at the distribution centre I am able
without appreciable loss to supply each circuit under the conditions that it demands.
Again when the distributing apparatus is a dynamo of either high or low tension, I
apply this invention at the dynamo itself using a corrector for the circuit or circuits
supplied by the said dynamo. Thus in the case of an alternator driven at a constant speed
and having a contant excitation I succeed in obtaining a constant potential difference
that increases with the load, giving a result similar to that known, in connection with
direct-current dynamos as "over-compounding." In this application of the corrector
to alternators the initial winding is connected to the terminals of the alternator
armature or to a portion only of the armature winding, preferably through a resistance
coil having some impedance while the other winding of the corrector is included in
the main or external circuit of the alternator. When several circuits radiate from one
alternator or from one common generating source 1 may use a separate corrector for
each circuit, suited to the requirements of such circuit.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
:-
1. In a parallel system of alternate current distribution such as herein referred, to
the combination with a transformer, or with an alternator, of a corrector or apparatus
constructed with magnetic material and with one or more coils or windings in such a
manner as to produce an opposing E.M.F., the amount of which diminishes as the
current increases, for the purposes herein set forth.
2. The use with a corrector or apparatus of the kind referred to in the preceding
claim constructed with two coils or windings of an impedance coil, or resistance, or
both, arranged in series with one of such coils or windings, substantially as herein
described for the purposes specified.
D:
1900
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.