US2043822A - Circuit breaker apparatus - Google Patents

Description

June 9, 1936. H. E. YOUNG 2,043,822

CIRCUIT BREAKER APPARATUS Filed Match 24, 1954 1720673757": if ya zzyz j I @W fflfi/w Patented June 9, 1936 j UNITED STATES PATENT OFFICE 12 Claims.

This invention relates to circuit breakers, and more particularly to a form of circuit breaker wherein the arc is dissipated electronically within an arc rectifying tube.

One feature of this invention is that, through the action of a controlled arc rectifying tube, it reduces the current to a substantially negligible value before the circuit is completely broken by a switch or other form of circuit breaker; still another feature of this invention is that it operates within a very small fraction of time, serving to completely quench any are within a half cycle of an alternating current; still other features and advantages of this invention will be apparent from the following specification and drawing.

Heretofore much trouble has been experienced with switches and circuit breakers which are upon being opened. Various means have been devised for dissipating the arc in oil or some other insulating medium, but all such mediums have been found to break down after'a certain period of use. This invention, however, permits a switch to be opened in air, and quences or dissipates the arc withina half cycle on an A. C. line.

In the particular embodiment of this invention illustrated a source of A. C. current is represented by the numeral ID from which extend two leads H and [2, the lead I! connecting with the load through the contact I 3, the switch blade l4, and the lead H5. The lead l2 connects with the contact It of the three pole knife switch 11, then through the blade 46 to a cathode l8 and the anode it in a controlled arc rectifying tube 20. This tube has an anode 2i co-operating with the cathode i8, and a cathode 22 co-operating with the anode i9, both of which are connected to a common point 23 from which a lead 24 completes the circuit to the load. The cathode l8 and the anode it are also connected to a common point 25. I

The primary 2B of a transformer 21 is connected across the lines H and I2. The secondary 28 of this transformer is connected to a phase splitting circuit, one terminal of the transformer being connected to a resistance 29 and the other terminal to an inductance 30, the inductance and the resistance having a common return circuit through the primary SI 'of the transformer 32 to the center tap 33 of the secondary 28. The transformer 32 has a split secondary, one of the secondaries 34 being connected to the grid 35 and to the common point 25 of the cathode i8 and the anode iii. The other secondary 36 is connected to the grid 31 and to the common point 23 of the cathode 22 and anode 2|. A split secondary transformer is necessary here, since if both grid return leads were connected to a common center point they would short the tube out of operation completely. A' short circuit for the inductance 38 is provided by the lead 38, the contact point 39, the switch blade 40, and the return lead 4|.

Two separate but co-operating tubes may, of course, be used in place of the single tube 20.

The switch I1 is the common type of knife blade switch wherein control may be achieved through manual operation of the handle 42-. The main current load is carried by the contacts I3 and I6 and their cooperating blades I4 and 46, while the center blade or contact 40 and its contact 39 serve only to control the phase-splitting circuit. The switch is so arranged that the main blades I4 and 46 maintain their connection for a brief interval after the blade 40 has broken away from the contact 39, as is shown by the position of the switch in the diagram.

The operation of this form of the invention is as follows:

The phase splitting circuit is adjusted so that when the inductance 30 is shorted out the potentials applied to the grids 35 and 31 will be in phase with the line potentials of the anodes l9 and 2|, and so that when the short circuit is opened and the inductance 30 is thrown into the phase splitting circuit the potentials on the grids will be substantially out of phase with those on the anodes. Assuming the switch to be completely closed and the line to be carrying current, the tube 20 will cause practically no voltage drop in the line since the potential on the grids will be in phase with that on the anodes. The apparatus in this condition will thus aiford no appreciable resistance to current flow. When the switch starts-to open, however, through manual operation of the handle 42, the blade 40 will separate from the contact 39 while the main line current is still passing through the blades l4 and Q6. The separation of the blade MI from the contact 39 opens the short circuit on the inductance 30 and thus throws the grid potentials practically 180 out of step with the anode potentials. In this condition the tube 20 offers a very high impedance to current how and permits no line current to pass to the load. The current-is'completely broken, and the switch may be left in the illustrated position if desired. The usual practice, however, would be to continue the movement of the switch until the blades 14 and 46 had also separated from their contacts. This separation would occur with no arcing, since there would blades. Since the tube serves to quench the current within a half cycle, it is only necessary for the blades l4 and 46 to maintain their contact for a very small fraction of a. second after the contacts 39 and 40 have separated. In the commercial current in use today this time interval between the opening of the blade 40 and then of the blades l4 and 46 would not have to be over 1/120 of a second, since that interval would be sufficient to completely quench the current through the tube. This interval is so short, in fact, that the switch can be opened with one manual motion, no pause being necessary. When it is desired to again close the circuit the blades l4 and 46 would make contact while the tube held the current to a minimum, and then the closing of the contacts 39 and 40 would permit the full current to pass to the load, thus preventing any sparking upon closing the main line. There would never be any arcing at the contact points 39 and 40, since they only carry sufficient current to energize the grids, which would not exceed a few milliamperes.

The word impedance is used herein to distinguish the control of current through a controlled arc rectifying tube from that of ordinary forms of resistance. The tube can eifectively block the current flowing therethrough without introducing any 1 R losses, as would be the case if the tube interposed a resistance to current flow in the technical sense in which that-word is used in the electrical art.

The particular embodiment of this invention illustrated is designed for lines having their requisite overload protection in the form of fuses or a separate circuit breaker. The switch il may be eliminated entirely, if it is so desired, and the contacts 39 and 40 incorporated with the circuit breaker, provision being made for them to separate before the main contacts of the circuit breaker.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and 'arrangement may be made ,without departing from the spirit and scope of the invention as disclosed in the appended claims, in which it is my intention to claim all novelty inherent in my invention as broadly as permissible in view of the prior art.

What I regard as new, and desire to secure by Letters Patent, is:

1. A circuit breaker system of the character describedHncIuding; two controlled arc rectifying means through which alternating current passes to the load; a switch carrying the load current; auxiliary contacts on said switch adapted to open before the opening of said switch, and to close after the closing of said switch; and a control circuit including said contacts whereby said rectifying means permit unimpeded flow of current while said auxiliary contacts are closed, but whereby said rectifying means interposes a high impedance to said current when said auxiliary contacts are open.

2. A circuit breaker system of the character described, including; a controlled arc rectifying after the main contacts close; and a phase shifting circuit controlled by said auxiliary contacts, whereby said tube permits unimpeded flow of the load current when the auxiliary contacts are closed, but interposes a high impedance to the flow of current when said auxiliary contacts are open.

3. Apparatus for breaking an A. C. circuit, in cluding; an arc rectifying tube in said circuit, said tube having two anodes and two associated cathodes so connected that alternating' current is passed by said tube; a control grid in said tube;

a phase-splitting circuit for normally imposing on the grid an alternating voltage substantially in phase with the anode voltage of said tube, said phase splitting circuit including two branches having a common return; and means for throwing said grid voltage out of phase with respect to said anode voltage before said circuit is broken, said means including means for altering the potential drop across one of the branches of said phasesplitting circuit.

4. Apparatus for breaking an A. C. circuit, including; a switch; a pair of grid controlled rectifying means in said circuit so connected that alternating current passes therethrough; a control grid in each rectifying means; a phase-splitting circuit for normally imposing on the grids an alternating voltage substantially in phase with the anode voltage of said rectifying means, said phase-splitting circuit including two branches having a common return; and means for throwing said grid voltage out of phase with respect to said anode voltage before said circuit is broken, said means including contacts associated with said switch whereby a short circuit for one of said branches .may be opened.

5. Apparatus for breaking an A. C. circuit, including; a switch; an arc rectifying tube in said circuit, said tube having two cathodes and two anodes therein so connected that alternating current passes through said tube; a control grid in said tube; a phase-splitting circuit for normally imposing on the grid an alternating voltage substantially in phase with the anode voltage of said tube, said phase-splitting circuit including a resistance branch and an inductance branch, both of said branches having a common return circuit, and a short circuit for one of said branches; and means for throwing said grid voltage out of phase with respect to said anode voltage before said A. C. circuit is broken, said means including means for removing said short circuit to shift said voltage.

6. The combination with an alternating current circuit, of a switch in said circuit, grid-controlled electron tube means interposed directly insaid circuit comprising a reversed relation 0! anodes and cathodes for passing the alternating currentload of said circuit, a phase shifting circuit fed from said alternating current circuit for supplying a phase controlled potential to the grids 01 said electron tube means, and automatic means actuated by initiationof the operation of said switch for controlling said phase shifting circuitto render said tube means substantially non-conductive in advance of opening of the circuit by said switch.

'7. The combination with an alternating current circuit, of circuit interrupting means comprising main contacts and auxiliary contacts, said main contacts being connected in said circuit, gridcontrolled electron tube means interposed directly in said circuit comprising a reversed relation of anodes and cathodes for passing the alternating current load of said circuit, and a phase shifting circuit responsive to the operation of said auxiliary contacts and operating to supply a phase controlled potential to the grids of said electron tube means, said auxiliary contacts and said main contacts operating in sequence in the operation of said circuit interrupting means, whereby said auxiliary contacts operate through said phase shifting circuit to shift the grid potential of said tube means relatively to the anode potential prior to the separation of said main contacts.

8. The combination with an alternating current circuit, of circuit interrupting means comprising main and auxiliary contacts, said main contacts being connected in said circuit, gridcontrolled electric valve means connected in said circuit between said circuit interrupting means and the load, said valve means comprising multiple electrodes connected to pass the alternating current to the load, a transformer connected to said circuit on the line side of said valve means, and a phase shifting network fed from said transformer and supplying grid potential to said valve means, said phase shifting network being controlled by said auxiliary contacts, said auxiliary contacts having a lead of operation over said main contacts in the operation oisaid 'circuit interrupting means whereby to shift the grid potential of said valve means prior to the separation of said main contacts.

9. The combination with an alternating-current circuit, of circuit interrupting means comprising main and auxiliary contacts, said main contacts being connected in said circuit, grid-- controlled electric valve means connected in said circuit, said valve means comprising multiple electrodes connected to pass the alternating current to the load, and a phase shifting network supplying grid potential to said valve meansand being controlled by said auxiliary contacts, said auxiliary contacts having a lead of operation over said main contacts in the operation of said circuit interrupting means whereby to shift the I grid potential of said valve means prior to the separation oi. said main contacts.

10. The combination with an alternating cur spect to the anode voltage, and means responsive to the motion of said operating member in a circuit interrupting'operation for causing said phase shitting network to eiieet phase displacement of the grid voltage prior to the separation 5 or said contacts. a 11. The combination with an alternating cur rent circuit, of circuit interrupting means connected in said circuit for opening the latter, electric valve means 01' the grid-controlled arc rectiiying type connected in said circuit, said valve means comprising a plurality of anode and cathode electrodes connected to permit substantially unimpeded flowoi' alternating current to the load when the grid potential of said valve means is substantially in phase with the anode potential, said valve means interposing a high impedance to such flow when the grid potential is substantially out 01' phase with the anode potential, phase shifting meansior shifting the 20 phase relationship of the grid and anode potentials, and means responsive to the actuation of said circuit interrupting means for controlling said phase shifting means to throw-the grid Dotential substantially out of phase with the anode 25 potential in advance of interruption of the circuit by said circuit interrupting means.

12. In combination with a source of alternating potential (IO-l0), an alternating current circuit (I 5-24) connected to saidsource, of a 30 main switch (14-46) for opening and closing said circuit, electric valve means (20) of the arc rectifying type provided with firing control -means (35-31) for controlling the passage of current through the valve means, said valve means (20) being connected in series with said switch (H48), a controllable excitation circuit (32) for said firing control means, said circuit being energized solely from said source, controllable phase shifting means (30) for said excitation circuit (32) for determining the phase of excitation supplied to said firing control means (31-35), a circuit changer (40-49) for governing said phase shifting means- (30) and common means (42) for operating the circuit changer (4039) and the main switch (ll-46), said common means (42) invariably causing operation 01 the phase shifting means (30) whereby said excitation circuit (32) affects the firing control means (31-35) to render the valve means (20) non-conductive in advance of opening of the main switch (IHB), and conversely said com-- mon operating means (42) causing operation of the phase shifting means (30) to render the valve means (20) conductive in advance of closll ing the main switch (ll-46) HUGH E. YOUNG

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