Improvements in Means for Automatically Regulating Electric Generators.
Year: 1886

page_text: Date of Application, 18th Dec., 1886
Complete Left, 19th Sept., 1887
Complete Accepted, 28th Oct., 1887
PROVISIONAL SPECIFICATION.
Improvements in Means for Automatically Regulating Electric
Generators.
We ROBERT PERCY SELLON Electrical Engineer WILLIAM MORRIS MORDEY
Electrician and CHARLES EDMUND WEBBER Major General R.E. C.B. all of Victoria
Works Belvedere Road in the County of Surrey do hereby declare the nature of our
said Invention to be as follows:―
Our Invention relates to the regulation of the supply of electrical energy derived
from alternate current machines.
In a system of distribution of Electrical energy for lighting heating or other
purposes it is usual to work either on the "series" system that is where the various
devices such as arc or incandescent lamps or groups of them are placed in electrical
series with one another or on the "parallel" system that is where the devices are
placed in derivation across the main wires supplying electricity.
In the first case the desideratum is to maintain a constant strength of current
throughout the circuit.
In the second case the desideratum is to maintain the electro motive force constant
at the points of consumption and approximately constant at the Dynamo Generators.
This Invention consists in means or methods of regulating the supply of electrical
energy from alternate current machines so as to attain either of these ends.
According to our Invention the excitation of the field magnet coils of the generator
or generators is obtained from a separate dynamo machine: the exciting current
yielded by this second machine is varied by means of an automatic regulator which
operates as follows
A magnet or magnets (wound in "series" relation to the main
wires supposing constant current to be the desideratum or in "shunt" relation to the
main wires supposing constant potential to be the desideratum) or other suitable
device cause by their action upon an armature or armatures the field magnets of the
second or exciting dynamo to be varied in strength such as by the action of a
resistance placed as a shunt or in series with the field magnets the extent of which
resistance is varied by the varying attracting force of the magnet or magnets.

page_text: Thus a variation from the constancy of the conditions of supply of the primary
generators will cause a corresponding variation in the magnet or magnets of the
automatic regulator: this again will cause a variation in the strength of the magnet
field of the second or exciting dynamo and so cause the latter to yield an increased or
diminished exciting current to the primary generator until the required conditions of
supply whether of constant current or constant potential are reestablished. The
tendency will be always to automatically maintain the conditions of supply as nearly
as possible constant.
Or we may employ an additional magnet (wound in "series "relation to the main
wires if constant current is required or in "shunt" relation to the main wires if
constant potential is required) or other suitable device which under small variations
from the normal conditions of supply may throw into operation suitable electrical or
mechanical devices for varying the strength of the magnet field of the second or
exciting dynamo as above described.
The above additional magnet thus operates as a relay. Or we may obtain the
major portion of the exciting current for the primary generator viz. that portion
constituting the fixed or minimum strength of field usual to all compound wound
self regulating machines-from the primary generator direct the current used for
this purpose being commuted so as to make it continuous within the machine; the
variable or correcting strength of field necessary to produce constant current or
constant potential under variations of external work being obtained by either of the
two methods already described. In place of employing the devices alluded to for
the purpose of varying the strength of the field of the separate excitor we may use
them for the purpose of varying the field of the alternate current generator directly
or by the alteration of a resistance placed in or across it. By this method a smaller
exciting Dynamo is required than would otherwise be the case.
Dated this 18th day of December 1886
J. HENRY JOHNSON,
Agent for the said Robert Percy Sellon,
William Morris Mordey, and Charles E. Webber.

page_text: COMPLETE SPECIFICATION.
Improvements in Means for Automatically Regulating Electric
Generators.
We ROBERT PERCY SELLON Electrical Engineer WILLIAM MORRIS MORDEY
Electrician and CHARLES EDMUND WEBBER C.B. Major General R.E. all of Victoria
Works Belvedere Road in the County of Surrey 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:-
Our Invention relates to the regulation of the supply of electrical energy derived
from alternate current machines.
In a system of distribution of electrical energy for lighting heating or other
purposes it is usual to work either on the "series" system that is where the various
devices such as are or incandescent lamps or groups of them are placed in electrical
series with one another or on the "parallel" system that is where the devices are
placed in derivation across the main wires supplying electricity-In the first case the
desideratum is to maintain a constant strength of current throughout the circuit.
In the second case the desideratum is to maintain the electro motive force constant
at the points of consumption and approximately constant at the electric generator or
generators. This Invention consists in means or methods of regulating the supply of
electrical energy from alternate current generators so as to attain either of these
ends. The accompanying drawings will serve to make clear the various methods
herein described for obtaining regulation of the supply of electrical energy from
alternate current dynamo electric machines. In the figures similar letters indicate
similar parts throughout.
According to our Invention the exciting current for the field magnet coils of the
generator or generators is usually obtained from a separate Dynamo machine. The
exciting current yielded by this second machine is varied by means of an automatic
regulator which operates as follows:-A magnet or magnets or other suitable devices
(connected in "series" relation to the main wires; supposing constant current to be
the desideratum, or in "shunt relation to the main wires supposing constant
potential to be the desideratum) cause by their action upon an armature or armatures
the field magnets of the second or exciting dynamo to be varied in strength such as
by the action of a resistance placed as a shunt or in series with the field magnets the
extent of which resistance is varied by the varying attracting force of the magnet or
magnets.
The controlling electro-magnet or its equivalent must be such as to be actuated by
alternating currents and we may make use of any device or principle such as the
expansion of a wire traversed by the current. Thus a variation from the constancy
of the conditions of supply of the primary generators will cause a corresponding
variation in the magnet or magnets of the automatic regulator, this again will cause a
variation in the strength of the magnetic field of the second or exciting generator and
so cause the latter to yield an increased or diminished exciting current to the

page_text: primary generator until the required conditions of supply whether of constant current
or constant potential are reestablished. The tendency will be always to automatically
maintain the conditions of supply as nearly constant as possible.
In figure 1A is the armature of an alternate current generator supplying electrical
energy to the mains at M M F the field magnet or magnets of the same supplied
with currents by the separate exciting dynamo D. The field winding of D being
shunted by the variable resistance R. The magnet S which controls the variable
resistance R is magnetized by being placed in connection with the mains M M'.
Suppose the conditions of supply in the main circuit M M depart from the normal
owing to variations in the number of lamps or other translating devices in operation,
then such variation will affect the magnet S causing it to alter the amount of resistance
in the shunt circuit at R so altering the strength of the exciting current passing in
the field magnet F until the normal conditions are again restored in the external
circuit M M Or any other suitable manner of control of F may be adopted, thus:-
The resistance by the variation of which regulation is obtained may be placed in the
exciting circuit F: Or the field F may be wound with a number of separate coils the
number of which in operation may be varied automatically for the same purpose and
by the same means. A Carbon resistance is preferred because the range of motion
required is small. Or we may employ an additional magnet or other suitable devices
connected in series" relation to the main wires if constant current be required or in
"shunt" relation to the main wires if constant potential be required which under
small variations from the normal conditions of supply may throw into operation
suitable electrical or mechanical devices for varying the strength of the magnetic
field of the second or exciting dynamo as above described. The above additional
magnet or other controlling device thus operates as a relay. Figure 2 illustrates this
part of our Invention. Variations from the normal in the external circuit M M'
which affect the magnet S cause the lever arm to close the circuit of either one or
other of the magnets e e¹ according as the conditions exceed, or fall short of, the
standard conditions in the external circuit M M¹. are the contacts for the lever
arm and m² m² are the circuit wires for the coils e e' led off the mains as shewn. By
a suitable devico such as the clutch C to which rotary or reciprocating motion is
imparted in any convenient way engaging in one or other of the clutch wheels W W
the resistance R in the exciting circuit is varied until equilibrium is again restored in
the external circuit. The arrangement shewn consists of a centered armature n
attracted to one side or the other by the cores of the coils e or el, according to which
coil receives current, so as to move the clutch C into gear with either the wheel W or
the wheel W which are mounted loosely on the shaft by which the clutch C is rotated
and so drive the wheel p and worm p² and so the quadrant and arm of the contact
maker for the resistance R in one or other direction to cut resistance in or out. Or
this arrangement may be employed to automatically control the field F in any other
suitable manner but the most economical and efficient is we consider that herein before
described viz.-by the variation of the field magnets of the separate exciter. Or we
may obtain the constant portion of the exciting current for the primary generator
viz. that portion constituting the fixed strength of field usual to all compound wound
self regulating machines from the primary generator direct, the current used for this
purpose being commutated so as to make it continuous within the said fields; the
variable or correcting strength of field necessary to produce constant current or
constant potential under variations of external work being obtained by either of the
two methods already described. Thus in Figure 3A represents the armature of
the alternate current dynamo machine a portion of the current produced by which as
shewn at a is used to excite the field F as shewn at f the current used for this purpose
being rendered continuous by the commutator K. "This provides the fixed portion of
the field magnetism. The variable portion as shewn at 1 may be obtained and
controlled as in either of the methods shewn in figures 1 and 2. Or we reverse the
arrangement and regulate by varying the exciting current obtained by commutation
from the alternate current generator-In place of employing the devices hereinbefore
described for the purpose of varying the strength of the field of the separate exciter

page_text: we may use them for the purpose of varying the field of the alternate current
generator directly as by the alteration of a resistance placed in or across it. This is
shewn in Figure 4. The whole of the exciting current necessary for the field F is
obtained from the armature A of the alternate current generator either from a separate
coil or winding or as a shunt from the mains or terminals. This exciting current is
rendered continuous by the commutator K and the necessary variation in strength is
produced by the resistance R either directly or by means of a relay placed either in
series with or as a shunt on the circuit of the field F but preferably the former. The
magnet S is as before described and shewn connected to the external circuit M M' as
a shunt on the mains, the arrangement being for parallel or constant electro-motive
force working For constant current working the coil S will be in series connection
with the mains. Any other suitable method of varying the field F may be used, for
example instead of using the resistance R the field F may be varied by being wound
with several coils or windings or sections the number of which in operation may be
varied automatically. The control may be either direct or by means of a relay
arrangement as described with reference to the previous figures.
Having now particularly described and ascertained the nature of our said Invention
and in what manner the same is to be performed we declare that what we claim is:-
First In a separately excited alternate current dynamo electric machine the
means for the automatic control of the field magnetism of the separate exciter
substantially as herein before described with reference to Figure 1 of the accompanying
diagrams.
Second In a separately excited alternate current dynamo electric machine the
automatic control of the field excitation by directly varying the resistance or the
number of coils in the exciting circuit substantially as hereinbefore described.
Third In a separately excited alternate current dynamo electric machine the
automatic control of the field magnetism of the separate exciter by means of a relay
device substantially as described with reference to Figure 2 of the accompanying
diagrams.
Fourth In a separately excited alternate current dynamo electric machine the
automatic control of the field magnetism by a relay device substantially as herein-
before described.
Fifth In a separately excited alternate current dynamo electric machine regulation
by partial excitation of the field by a commutated current from the alternate current
arniature and partly by current supplied from a separate exciter the automatic control
being exerted on either (or both) of these as bereinbefore described with reference to
Figure 3 of the accompanying diagrams.
Sixth-In a separately excited alternate current dynamo electric machine regulation
by automatically varying the strength of the field substantially as herein before
described.