US1723858A - Circuit breaker - Google Patents

Description

Au .6,1929. w, UL 1,723,ssa

' CIRCUIT BREAKER Filed Aug. 4, 1921 Fig.1.

R, Y I V V I! 40 HEMP k Fig. 5. E Inventor: Albert WQHUII,

1 /r fi /Vm/ MAG/V5776 HELD i His Attorney- Patented Aug. 6, 1 929.

' UNITED STATES PATENT OFFECE.

ALBERT W. HULL, OF SCHENECTADY, NEW YORK, ASSIGNOR T GENERAL ELECTRIC COMPANY, A CORPORATION OF N EW YORK.

cmcui'r BREAKER.

Application filed August 4, 1921. Serial No. 489,823.

My present invention comprise a circuit breaker or switch which is particularly adapted for the interruption of high voltage urrents. It is the object of my invention to provide anapparatus for safely interrupting powerful electrical currents with a minimum of disturbance to the transmission line.

In accordance with my invention I have provided an apparatus whereby the current is reduced to zero by a field of force operating on an'electron discharge in a vacuum, thereby preventing arcing, with no accompanying surges or other disturbances.

everal embodiments of my invention have been shown in the accompanying drawing in which Figs. 1 and 2 illustrate respectively by diagram an alternating current system and a direct current system equipped with a circuit breaking apparatus embodying my invention; Fig. 3 is a graph of electrical characteristics involved in the operation of my new apparatus; and Fig. 4 illustrates diagran'imatically a system in which the circuit is opened automatically when an unusual rise of current occurs.

Fig. 2 represents one of the simplest embodiments of my invention; namely, a direct current system comprising a generator connected to mains 5 and 6, an electron discharge tube 7 being adapted to be intercalated in the conductor 6 by opening a switch 7. The electron device 7 comprises a cylindrical anode 8 surrounding a filamentary linear cathode 9 and an enclosing evacuated envelo e 10. The cathode is connected by a CODClTlCtOl 11 to a source of en ergy, represented by a battery 12, whereby the cathode may be rendered incandescent. Surrounding the envelope is a helical magnetic winding 18 connected to a source of.

current, such, for example, as a battery 1 1 by a circuit 15 containing a switch 16.

The device 7 is known as a magnetron and is hereinafter in this specification and claims referred to by this term. The magnetron in a general aspect is described and tainied in my Patents No. 1,523,77 6 issued Januar 20, 1925, and No. 1,523,778 also issued anuary 20, 1925 and in the Trans actions of the American Institute of Electrical Engineers, for September, 1921. In the preferred embodiment of a magnetron illustrated in the drawings, the cathode is substantially equidistant from the anode at all points along its length. Other constructions affording circular symmetry of the electrodes may be used. The evacuation of the devi e preferably is so complete that positive ionization of residual gas is negligible although this is not essential.

Assuming the double pole switch 17 in the mains 5 and 6 closed and the switch 7 closed, the following sequence of steps may be carried out when it is desired to open the circuit which may be of high voltage. The switch 18 in the cathode heating circuit 11 is closed thereby bringing the cathode of the magnetron to a state of incandescence at which it emits electrons. The switch 7 in parallel with the magnetron is thereupon opened, causing the current in the conductors 5 and 6 to be carried entirely by the magnetron. The opening of this switch 7 is unaccompanied by sparking or disturbances due to the relatively low voltage drop in the magnetron. The switch 16 in circuit with the winding 13 is next closed, generating an electromagnetic field substantially parallel to the cathode. Theeifect of this field is to deflect the electrons carrying the current in the space between the electrodes causing the electrons to assume circular paths about the cathode and preventing them from reaching the anode. 4

Fig. 3 shows the relation between-current in the device and the magnetic field, the current values being plotted as ordinates and the values of the magnetic field being plotted as abscissae. It will be noted from the curve 20 that up to a value it of the magnetic field, the current is substantially unaflected but a further increase of the mag netic field causes an abrupt decrease of current so that at a value 70 the current has fallen to substantially zero. The value oi the magnetic field generated by the winding 13 is chosen to cause the current to fall to Zero orsubstantially so. v

A double pole switch 17, which may be mechanically operated, finally may be.

ened disconnectin the mains 5 and 6 ermanently. The switches 16 and 18 there u on ma be disconnected if desired takin P y a 3 they electron discharge tube out of service. The action of the magnetic field in reducing the current is unaccompanied bysurges and other disturbances in the circuit and of I course'being in a vacuumis free from the conditions.

danger which is present when arcing takes place in the open air.

Fig. 1 shows two magnetrons 21, 22, connected to an alternating current circuit 23,

24, these devices being oppositely connected in series with the alternating current circuit and'being adapted to carry current derived from the secondary winding of a transformer 25. The anode of the tube 21 and the. cathode ofthe tube 22 are both connected to the main 23, the cathode of the tube 21 and the anode of tube 22 being connected to the conductor 26, which isa continuation of the conductor 23. When the switch 27 isopened current of one polarity will pass through the tube 21 and current-0f opposite polarity through the tube 22. The cathodes of tubes 21, 22 are respectively heated by batteries 28, 29, or other suitable sourcespf current. When it is desired to disconnect the alternating current circuit.

from the load 30 the switch 27 is opened, inserting the magnetrons in circuit.

switch 31 then is closed energizing the ma gnetic windings 32, 33, and thereby setting up in the current carrying path'of each tube a field of force which deflects the electrons, as already explained, and reduces the current to zero or substantially so. The mechanically operated switch 34 in the conductor 26' may thereupon be opened. The magnetrons having performed their function and being cut out of circuit may be deenergized if desired.

Fig. 4 shows a magnetron adapted to be connected automatically. with the mains 36, 37 which carry current froma direct current generator 38. The cathode 9 is energized by a suitable source of. current such as a battery 39 in circuit with conductors- 40, 41, containing a mechanically operated contact 42. This contact is operated by a magnet 43, which is one of a group of sequentially operated magnets connected in series with the main 36. The electric and magnetic characteristics of the magnet 43 and its armature are so chosen that the contact 42 is open during normal current When an unusual rise of current occurs in the mains 36, .37, the magnet 42 pulls up its armature closing the contact 42, thereby heating to incandescence the cathode 9 of the magnetron. The magnet 45 is timed to next attract its armature 46 and open normally closed contact 47, thereby causing current to flow through themagnetron instead of through the conductors 48, 49. The magnet 50 will next attract its armature, closing thecontact 51 ina circuit 52, energizing the magnetizing winding 13, and cutting oil'current in the magnetron 35. The magnet 53 will operate next by opening the contacts 54 in the circuit 55, 56. -The switch 57 may finally be opened manually or otherwise, thereby permanently opening the current carrying mains.

It is is desired to open the circuit very quickly, as in case'of a short circuit, the cathode of the magnetron may be maintained continually at incandescence by permanently closing the contact 42, or means may be used for auxiliary heating depend ing on the rate of change of current in the line 36, 37. I have indicated'as illustrative netron cathode a transformer 60 having a primary connected in the line 37 and containing a condenser 61 in thesecondary to of auxiliary heating means for the mag-,

prevent discharge of the battery. A choke coil 62in the battery circuit may also be provided topreve'nt discharge of the transformer current through the battery, circuit.

When in the accompanying claims I have inserting the same into said circuit and en- Y erglzing the field winding of said magnetron to a strength sufficient to interrupt said current, and means for thereupon disconnecting said magnetron.

. 2. A switching apparatus comprising a.

circuit to be opened and closed, a magnetron, connections for including said magnetron in said circuit and a plurality of sequentially operated contactors, constituted first,

.by a contactor having a. contact included in the cathode heating circuit of said magnetron? second, a contactor having a contact in multiple with, said magnetron; third, a contactor having a contactin the magnetizing circuit of said magnetron and fourth,a contactor in series with said magnetron, said contactors being timed to operate in the order named.

3. A current control apparatus including a normally energized circuit to be opened and closed, a normally deenergized magnetron, means for inserting and withdrawingsaid magnetron. from said circuit and means controlled in accordance with an electrical condition of said circu1t for creating 1n said magnetron a magnetlc field vof sufficient value to reduce the current the cathode and magnetic winding of said magnetron, and a second contactor in series with the electrodes of said magnetron.

5. The combination of-an electrical power circuit, a switch connected in said circuit, an electron discharge device including an anode connected to one terminal of said switch and a cathode connected to the other terminal of said switch, means for energizing said device, means for opening said switch, and means for dcenergizing said device, said means being responsive to a predetermined electrical condition of said circuit.

6. The combination of an electrical power circuit, a switch connected in said circuit, an electron discharge device including an anode connected to one terminal of said switch and a cathode connected to the other terminal of said switch, means for energizing said device, means for opening said switch, means for deenergizing said device, and means for opening said circuit, said means being responsive in sequence in the order named, to a predetermined electrical condition of said circuit.

In witness whereof, I have hereunto set my hand this 3rd day of August, 1921.

v ALBERT W. HULL.

Images