Year: 1887

page_text: Date of Application, 12th July, 1887.
Specification Accepted, 2nd Sept., 1887.
[Communicated from abroad by GEORGE WESTINGHOUSE, Junr., of Pittsburg, County
of Alleghany, State of Pennsylvania, United States of America, Engineer.]
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool, and 6 Bank Street, Manchester, both in
the county of Lancaster, and 323 High Holborn, in the county of Middlesex, Civil
Engineer, 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 the invention is to provide means for determining the relative phases
of two or more electric generators for delivering alternating currents, for the purpose
of rendering it possible to bring them together in multiple-arc circuit without injury
to the circuits which they are designed to supply.
In operating systems of electric distribution supplied by alternate current generators,
it is sometimes desired to couple in multiple-are more than one generator with the
distributing conductors. In practice it has been found that two generators running
at approximately the same rate, or delivering approximately the same number of
alternating impulses per minute, will, when connected in multiple-are circuit, tend
to fall into synchronism with each other, and if a slight slippage of the belts be
allowed, they will continue to run in unison, when once started. As it is practically
impossible however to determine from observation of the machines themselves the
exact phases of the currents, there is a probability that the two machines would be
out of synchronism and possibility in opposite phases with reference to the main line,
when coupled together. This would result in such a combination of the currents as to
cause each machine to short-circuit through the other. In other words, the currents
of the two machines would combine and flow in the same direction through the
conductors connecting the two machines and practically no current would flow upon
the outside circuit. The machines might, however, ultimately come into synchronism,
but not only would there be caused irregularities in the action of the lamps or other
+

page_text: translating devices in the exterior circuit, but a more serious difficulty would result
from the combination of the two currents in the supply circuit, namely, the burning
out of the safety-catches by reason of the abnormal strength of the current. This will
become more evident upon a consideration of figure 1, in the accompanying drawings,
which is a theoretical diagram illustrating the resultant current produced by the
combination of the currents of two machines in varying phases. Figure 2 is a diagram
illustrating an organization of circuits and apparatus adapted to carry out the invention,
and figures 3 and 4 illustrate modifications. Referring first to figure 2, G and G¹
represent two alternate-current generators, and L and L' the two main lines to which
they deliver their currents. The generator G has its respective brushes a and b
connected by conductors 1 and 2, with two switch-points and k respectively. A
switch K serves, when closed, to place these two points in connection through
conductors 3 and 4 with the two lines L and L' respectively.
From the points i and k conductors 5 and 6 lead to two switch-points hand i
respectively. A switch H serves, when closed, to place these two points in connection
with the conductors 3 and 4 respectively, thus forming a shunt around the switch K.
In one of these shunt-conductors, the conductor 6, for instance, there is included the
primary coil p of an electric converter C. The secondary coils of this converter
includes in its circuit a lamp or other indicating device d.
The generator G¹ is equipped in precisely the same manner, corresponding letters
of reference having numeral 1 affixed, indicating corresponding parts.
From the lines L and L' are derived pairs of feeders 1, 11, 12, 13, 14, 15 etcetera. These
are designed to supply a system of translating devices of any desired character as for
instance, they are here represented as being derived from the secondary coils of
converters C, C3, C4, the primary coils of which are connected in multiple-arc with the
main lines Land L. Translating devices d², d³, d, are connected in the several
circuits in a manner well understood. The primary coils of the converters are
preferably capable of being connected with, and disconnected from the main lines by
means of switch-plugs o or in any other convenient manner.
For convenience of illustration, the lines and 13 are represented as connected in
circuit, in the present instance. The current flowing through these conductors will,
it is evident, be dependent upon the difference of potential between the two conductors
Land L'; but when one generator is connected therewith, this may readily be deter-
mined, being dependent entirely upon the current from that generator, but when a
second generator is connected in circuit, the currents of the two generators may
combine or they may to a greater or less extent oppose each other and produce a
resultant difference of potential lower than that from the single generator. This will
he more readily understood by reference to the diagram figure 1. In this figure the
full line represents the current from one machine, the machine G₁ for instance, and
the dotted line x¹ the current from the other machine G with reference to a normal y, 4
which represents the neutral condition of the lines L and L' relative to any flow of
current from one machine to the other. The heavy full-line z represents the resultant
current.
Now assuming the two machines to be connected with the line L and L' when in
opposite phases, that is to say, when the currents from the electric generator G instead 4
of combining with those from the generator G₁ to supply the intermediate branch
conductors and 13 (figure 2) as indicated by the arrows vv and v vl in figure 2,
are simply added to each other and flow in the same direction as indicated by the
arrows and the dotted arrows 22. These currents will, it is evident, flow from
one machine through the short circuit formed by the other, and will thereby not only 5
increase the current through the lines L, L' beyond the normal capacity, but will at
the same time withdraw the supply from the lamps or other translating devices, and
also endanger the safety devices shown at E E. These devices E consist of two fusible
strips E¹, E, one or the other of which is designed to be placed in circuit. These
strips are respectively fastened at one end to a plate E', and at their remaining ends 5
with two individual plates e² and e. These latter plates are designed to be placed in
connection with a central plato e by means of a switch-plug e accordingly as it is

page_text: designed to connect one or the other strip in circuit. The conductors leading to and
from the safety strip are respectively connected with the plates and e¹. In case,
therefore, one of the safety strips is burned out, the other may be substituted by
moving the pluge. The strips may be both short-circuited by a plug inserted at e*,
to connect the plates e¹ and e.
In the diagram (figure 1) the resultant current is illustrated by the heavy line z.
Assuming further that the phases of the current x, gain in frequency upon those of
the current x, then the resultant current will gradually approach more nearly to the
normal y, and the moment the two generators are in exactly opposite phases, the line =
will coincide with the normal y. If the two generators were coupled at this moment
no change of fluctuation in the light would be observed, and no current from the one
generator would flow through the other, since the line y, represents the absence of any
current through the circuit L, L' and the generators. Assuming the switch K¹ to be
closed and the switch K open, then if the switch H be also closed, a current from the
generator G will traverse the coil p of the converter and cause the indicating
device d to be operated. If this be an incandescent lamp it will burn with a certain
brilliancy. This brilliancy will depend, however, upon the combined action of the
two generators, for if the currents in the generator G¹ be such as to coincide with
those from the generator G, then the lamp will be operated by the current due to the
added electromotive forces of the two generators and it will burn at its highest degree
of brilliancy. When, however, the generators are synchronous, the lamp will be fed
by the current due to the difference of the electromotive force of the two generators
and will be at its lowest brilliancy. If the two machines are adjusted to give the same
electromotive force then no current will flow and the lamp will not light up.
For the purpose of determining the work being done by the respective generators,
two ammeters T and T' may be included in circuit with the respective generators.
The lamp d will thus indicate the proper period for closing the switch K and
connecting the generator G in full circuit with the conductor L, L', it being under-
stood that the coil has only enough inductive resistance to permit the flow of a
sufficient current to operate the device d in the required manner. By watching the
rise and fall of the visual indicator d for a few moments, the attendant may readily
determine the rate at which the phases change and the proper moment for closing the
switch, and when once thus brought into synchronism, the two machines will continue
to operate in unison owing to the dynamic effects which each machine exerts upon the
other. The switch H may then be opened or not as found desirable.
Were the generator G first in circuit, the generator G₁ would then be connected
in circuit at the proper moment by means of the indicator d' and switch K¹.
It will be understood that other arrangements of indicators may be used, for
instance, the indicator d may be placed as shown in figure 3 in the circuit of the
conductor 6, a resistance R being employed for determining the current which shall
flow through the conductor. Other methods of indicating the resultant current may
of course be employed.
the
Referring to figure 4 there is here shown a special device intended to be used for
purposes of this invention. A represents a suitable enclosing case or box for
containing the electric converter or induction coil C. This converter may be con-
structed in any well-known form, preferably, however, it consists of thin plates of
metal e enclosing a primary coil P and a secondary coil S. One terminal of the
primary coil P is connected permanently by a conductor 1 with a binding post B¹ at
the top of the box A, and this binding post is connected by a conductor 2 with one
of the conductors L¹ of a distributing circuit L'. The remaining terminal of the
rimary coil is connected by conductor 3 with a switch arm K' placed upon the door
f the box. This arm is provided with two contact points k³, k³, and a resting point k.
The point is connected through the hinge of the lid with a binding post B² and
be point is connected through the hinge with the binding post B³. When
herefore the switch arm K' is upon the point, the connections of the primary coil
ill be continued to the binding post B. It is designed that the circuit shall be

page_text: completed from the binding post B³ or B³ through a conductor 5 or 4 leading from
one pole of an electric generator G or G₁ accordingly as it is designed that the
generator G or G¹ shall be connected in circuit with the one already in operation.
If therefore the generator G¹ is delivering a current upon the lines L, L³, and it is
desired to couple the generator G' in multiple-arc, it is necessary that the two should
be made to coincide and deliver the same current at the moment the connections are
completed. To this end the connections of the respective dynamos with the lines L³, L
are through conductors to, te, t7 and 8, which include circuit interrupting switches
t, 1, 3, respectively. The switches t³ and being closed the switch 2 may also be
closed and the switch arm K³ placed against the point k². This will complete the
circuit of the primary coil of the converter. It is desired, however, that the circuit
of the secondary coil be completed through some indicating device which shall
determine whether or not the currents of the two generators combine to flow in the
same direction, or whether they unite to supply the feeders 1, 1, 1, 1, etcetera, which
include the translating devices d', d³, d, in multiple-are circuit. For this purpose
the respective terminals of the secondary coil S are connected with the terminals of the
incandescent electric light d, placed in a socket upon the top of the box.
In case the generator G is already in circuit, and the generator G¹ is to be con-
nected, the switch arm K' is moved to the point . In either case the full connections
are to be made by means of the switches t¹, t, substituting thereby the connection
directly with the lines L', L³, and the corresponding connection through the lines 5
and 4 may then be interrupted by moving the arm K to the point k.
Having now particularly described and ascertained the nature of the said Invention,
and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I declare that what I claim is :-
1. The hereinbefore described method of bringing an alternate-current electric
generator into multiple-arc with another similar generator when both are in action,
which consists in first connecting it through a circuit of high resistance, indicating
the current traversing this circuit, and thereby noting the relative phases of the two
generators, and at a moment when the phases are synchronous, connecting the
generator independently of the resistance.
2. The herein before described method of connecting alternate current electric
generators with a work-circuit when in action which consists in first connecting them
with each other through a resistance circuit, indicating the resultant current traversing
the circuit, and at the moment of minimum current through said resistance circuit,
shunting or cutting out the resistance.
3. The combination with an alternate-current generator, and a circuit supplied
therefrom, of a second alternate-current generator, a resistance-circuit through which
the second generator may be connected in multiple-arc with said circuit, an indicating
device operated by the currents traversing the resistance-circuit, and means for cutting
out the resistance and indicating device.
4. The combination of one or more alternate-current electric generators, a circuit
for the same, translating devices fed from said circuit, a second generator, a circuit
through which said generators may be connected in multiple-are with the translating
devices, an indicator in said circuit operated by the resultant current from all the
machines, and means for connecting the second generator independently of the
indicating device.
5. The combination of an alternate-current electric generator, a supply-circuit fed
therefrom, a second alternate-current generator, means for connecting the same with
said circuit in multiple-arc with the first, an electric converter, means for connecting
the primary coil of the converter in the circuit of the second generator, and an
indicating device included in the circuit of the secondary coil of the converter.
6. The combination substantially as described, of an alternate-current electric
generator, a supply circuit, a second generator, connections whereby the generators
may be connected with the circuit either independently or in multiple-arc with each

page_text: other, an indicating device for each generator, and means for causing at will the
current from either generator or the resultant current from both generators, to operate
the corresponding indicating device.
7. The combination with a system of electrical distribution, of two alternate current
electric generators, one connected in circuit with said system, circuit-connections
whereby the second may be placed in parallel circuit therewith, an electrical con-
verter having one terminal of its primary coils connected in circuit with said
distributing system, a switch for placing the other terminal in connection with the
other generator, and an incandescent electric lamp or other indicating device included
in the circuit of the secondary coil of said converter.
8. In an apparatus for connecting alternate-current electric generators in multiple-
are, an electric converter having one terminal of its primary coil adapted to be
connected with either generator, a switch for placing the other terminal in connection
with the other generator, and an indicating device included in the circuit of the
secondary coil of the converter, substantially as described.
9. The combination of two alternate-current electric generators, an electric
converter, means for placing one terminal of the primary coil of the same in con-
nection with either generator, a switch for placing the other terminal of the primary
coil in connection with the corresponding pole of the other generator, an electric
circuit with which the circuit of the first named generator is complete, means for
completing the connections of the other generator with said circuit in multiple-arc
with the first-named generator, and an indicating device included in the circuit with
the secondary coil of said converter.
10. The combination, substantially as hereinbefore set forth, with an inductive
electric resistance, a circuit including the same, and an indicating device operated by
the current traversing such resistance, of two alternate current electric generators,
switches for placing said generators in multiple-arc connection through said resistance
and means for placing the generators in multiple are connection independently of
said resistance.
11. The combination with two alternate-current electric generators, of a main
circuit, means for connecting either generator with said circuit at will in full circuit,
an indicating device consisting of a converter adapted to have its primary coil
connected in circuit with either generator at will, and an incandescent electric lamp
included in the secondary circuit of the converter.
12. A safety-device for electric circuits, consisting of two fusible strips, a binding-
plate with which they are both connected, two insulated plates with which the
remaining ends of said strips are respectively connected, and a second binding-plate
adapted to be placed in electrical connection with any of the other plates.
13. The combination with an alternate-current electric generator, of a circuit
supplied therefrom, a second alternate-current electric generator, a resistance circuit
through which the second generator may be connected in multiple arc with said
circuit, means for cutting out said resistance circuit, and a safety-plug applied to the
system of circuits consisting of a fusible strip and a short-circuiting device therefor
substantially as described.
1904