US3514553A - Controlled plasma moving electrical connector - Google Patents

Description

May 26, 1970 A. w. PENNEY, JR., EI'AL 3,514,553

CONTROLLED PLASMA MOVING ELECTRICAL CONNECTOR Filed Nov. 1. 1967 F/G.

L EI 5 8 2 5817/1 i A r: I H E Z 5 26 W Z0 F/G.3

POWER SOURCE 2 Kk/F AKJ) INVENTORS 7 ALBERT w. PENNEY, JR.

. ROBERT H. BULLIS EDWARD A.-PINSLEY ATTORNEY May 26, 1970 A. w. PENNEY, JR.. ET 5 5 CONTROLLED PLASMA MOVING ELECTRICAL CONNECTOR Filed Nov. 1. 1967 2 Sheets-Sheet 2 United States Patent U.S. Cl. 19156 2 Claims ABSTRACT OF THE DISCLOSURE Contact-type electrical connectors currently used to conduct electricity between a moving conductor and a fixed conductor, such as in rotary electric machinery or between stationary conductors and moving vehicles, are replaced by a highly ionized plasma of high electrical conductivity. Rotary electrodes ensure that all electrode surfaces have relative motion with respect to the discharge. In a moving vehicle embodiment, a rotary electrode is mounted on the vehicle and the discharge takes place to a stationary catenary wire; in a rotary machinery embodiment, a pair of rotary electrodes, each conducting through a plasma to the slip ring or commutator of a rotary machine, replace brushes or shoes normally used therewith. Electrodes of copper or other suitable conductor may have low ionization materials embedded therein to enhance the current carrying capability of the plasma.

BACKGROUND OF THE INVENTION Field of invention This invention relates to electrical connection between relatively moving electrical conductors, and more particularly to the use of a current carrying plasma therefor.

Description of the prior art State of the art moving electrical connectors are limited in operating range by several major problems. In order to maintain reasonable losses at the point of contact, mechanical systems require a large normal force between the stationary moving surfaces, such as between the brush and armature of a rotary electrical machine, or between the shoe and catenary wire of a moving vehicle. This large normal force produces an abnormally high amount of friction, which results in excessive wear and heating of the shoe or brush, as the case may be.

As is well known, even at moderate relative speeds, mechanical imperfections in the system result in uncontrolled arcing which causes severe degradation in the mechanical components of the system, resulting in highreplacement cost, and in some cases catastrophic failure while in operation.

An additional problem with moving vehicles relates to the sliding of a shoe along a suspended power transmission line since the force normal to the line applied by the shoe creates mechanical oscillations along the length of the line behind the point of contact. These induced mechanical oscillations add further difficulty in maintaining a good sliding contact between the shoe and the transmission line. Furthermore, the speed at which a shoe can slide along a transmission line is definitely limited by friction and contact problems, and, therefore, can impose a maximum operating speed on a moving vehicle. This can result from the maximum speed at which the mechanics of the system can function, or may result from limitations in power (and therefore speed) which can be transferred by such a sliding contact with are damage (which results from mechanical imperfections) that result at higher speeds. Additionally, due to the need for ice long lengths of large diameter electrical cable, it has heretofore been impossible to create an ideal contact situation for mechanical connections between a moving vehicle and a catenary transmission line.

At very high speeds, it is difficult and costly to develop a servo system or a spring-loaded system which will guarantee good electrical contact between a long whipping transmission line and the contacting shoe on a vehicle. At higher speeds, the ability of the system to repsond quickly enough to variations in height, diameter or condition of the conducting wire so as to insure good electrical contact is severly limited.

SUMMARY OF INVENTION The object of the present invention is to provide electrical connection between moving electrical conductors in which problems of uncontrolled arcing, excessive wear, mechanical alignment and lubrication are mitigated or eliminated.

Another object of the invention is the elimination of speed limitations imposed by the need for mechanical contact between relatively moving electrical conductors in rotary machinery and moving vehicles between which electrical contact must be made.

According to the present invention, contact between relatively moving eletcrical conductors is made by a controlled plasma having high current carrying capability. In further accord with the present invention, the position at which the plasma column impinges on the surface of an electrode, which is nominally stationary with respect to the plasma, is varied so as to mitigate heat and erosion problems therewith, and in addition, concomitant power. In accordance still further with the present invention, the electric current capability of the plasma is enhanced by providing low ionization materials or compounds thereof in the area of the plasma.

Still further aspects of the present invention relate to details of effecting rotary motion of a plasma electrode, and to gaseous deionization of the plasma area for the purpose of interruption of current through the plasma.

The present invention further contemplates use of a controlled environmental atmosphere in the area of the plasma to enhance the current carrying capacity and control thereover, including the ability to interrupt the current therein by introduction of a small, controlled amount of electro negative gas into the atmosphere. The controlled atmosphere may be combined with the flow of coolant gases utilized in heavy machinery in some cases. In order to avoid excessive heating and material depletion of the electrical contact with respect to which the plasma is normally moving, the invention also encompasses utilization of a solid contact during a startup operation and at low speeds, with the solid contact being withdrawn once a certain operating speed has been reached, plasma conduction taking over from mechanical sliding conduction at that point.

The foregoing and other objects, features and advantages of the present invention will become more apparent in the light of the following detailed description of preferred embodiments thereof, as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a simplified plan view of a rotary machinery embodiment of the present invention;

FIG. 2 is an elevation view taken along the line 22 in FIG. 1;

FIG. 3 is a pictorial block diagram of a moving vehicle system illustrating operation of the invention at high speeds;

FIG. 4 is a partial elevation view illustrating operation of the system of FIG. 3 at low speed;

FIG. 5 is a partially broken away and sectioned front elevation view of an electrode in accordance with the present invention suitable for use in the system illustrated in FIGS. 3 and 4;

FIG. 6 is a partially sectioned elevation view taken on the line 66 in FIG. 5; and

FIGS. 7 and 8 illustrate a variation of the embodiment of FIGS. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, a conventional rotary electric machine, such as a DC motor 10 includes an armature 12 and a pair of field windings 14, 16. A commutator or slip ring 18 of the machine 10, positioned between a pair of rotatable electrodes 20, 22, is in conduction with the electrodes 20, 22 through regions of plasma 24. Alternatively, the electrodes 20, 22 may be mounted on axes parallel with the axis of the motor, as in FIGS. 7 and 8, whereby the electrodes may touch the motor while it starts up and then be moved away from it thereby striking an arc to initiate plasma conduction, since the axes are parallel, the electrodes will roll with the motion of the commutator 18 until such time as they are moved away therefrom and the arc is struck. Thereafter, these discs would rotate under the eddy current forces described hereinafter. The discs may be moved into and out of contact with the armature 12 by any suitable linkage 80 (FIGS. 7 and 8) by a servo system 82 in response to a conventional centrifugal governor system (not shown). Other suitable arrangements may of course be selected from many known in the art. The invention may also be incorporated in a generator system as well as in a motor system.

In order to prevent destructive erosion of the electrodes 20, 22, a magnetic field (indicated by arrows 27 in FIG. 2 and arrows 27' in FIG. 7) is provided so as to permit eddy current motor action to turn the electrodes 20, 22. This results from the current being conducted by the electrode 20, 22 interacting with the magnetic field under the principle of Faradays disc dynamo. This is described in detail in Section 316 of Dawes, Electrical Engineering, McGraw-Hill, 1952.

The electrodes 20, 22 are suitably journalled on corresponding shafts 26, 28 by means of suitably electricalconducting bearings, an example of which is described with respect to FIG. 5 hereinafter. Briefly, suitable bearings might be sealed bearings filled with mercury so that conduction takes place on spatially uniform bases rather than through points of contact between the bearings and the bearing races. Therefore, metallic conduction into any sort of control or utilization system from the electrodes 20, 22 (and therefore electrical connection to the motor itself) can be made from the nonrotating shafts 26, 28 to which the electrodes 20, 22 are journalled. Of course, suitable mountings for the shafts must be provided in accordance with the teachings of the prior art, which havev been eliminated from FIGS. 1 and 2 for simplicity herein. As illustrated only in FIG. 2 for simplicity, the embodiment of FIGS. 1 and 2 may have gaseous control over the arc supplied thereto through the mechanism of a well-known controlled atmosphere system. As illustrated in FIG. 2, sources of a highly-ionizable gas 30, an electronegative gas 32 and regular coolant gas 34 may be supplied to a valve 36 which is positionable by control 38, as is well known in the fluid dynamics arts. Thus when the rotary machine 10 is started, the valve 36 may be positioned by the control 38 so as to pass highly ionizable gas from the source 30 into the controlled environment chamber 40. This enhances the establishment of a plasma discharge between each of the electrodes 20, 22 and the commutator or slip ring 18. Thereafter, the control 38 may position the valve 36 to supply ordinary coolant gas from the source 34 to the controlled environment chamber 40 so that the motor can run in a controlled environment as is well known in the art. When stopping of the motor is desired, rather than relying on complex and expensive switches, the plasma 24 may be extinguished by introducing an electro-negative gas from the source 32 through the valve 35 and into the chamber 40, whereby the plasma cannot be sustained and the machine will be turned off.

In FIGS. 3-6 is illustrated a moving vehicle embodiment of the present invention wherein a moving vehicle such as a train 50 is supplied with a pantograph member 52 including a servo mechanism 54 as is well known in the art. The servo mechanism 54 is used to make approximate adjustments in the height of a pantograph 52, such as when entering tunnels, and for high/low speed operational adjustments, as is described hereinafter with respect to one aspect of the present invention. The servo 54 may be controlled by suitable means known to the prior art so as to raise and lower it in response to a servo and start up control 56. The control 56 includes well known course positioning controls responsive to a position sensing means 57, and also includes means for overriding the normal raising and lowering by a small amount, the amount equal to the length of plasma which is desirable in any given utilization of the present invention. The sensing means 57 may be a simple arm guided by opposing rollers 59 so that the arm 61 pivots as the distance between the pantograph and catenary varies. The arm may operate any well-known transducer such as a potentiometer. Thus, when the train is at rest and just starting up, or when the train is slowing down to come to a stop, the pantograph 52 may be moved upwardly so that a rotary electrode 58 may be in contact with the catenary wire 60, conducting current more or less in the same fashion as is currently done with a sliding shoe. If required, for a larger current-conducting contact area, an auxiliary sliding shoe may be provided to assist the electrode 58 at low speeds. The catenary wire may be supported from a messenger wire 62 as is well known in the art.

In accordance with one aspect of the present invention, when a vehicle such as a train 50 is operating at low speed (such as below 60 miles per hour) the electrode 58 may be in contact with the catenary wire 60. However, once the speed of the train exceeds 60 miles per hour, then the control 56 causes the pantograph to lower from the normal position thereof by an amount equal to the length of plasma required, and in the process of lowering, an arc is struck between the electrode 58 and the catenary wire 60. Thus a full, current-conducting plasma will develop, so that when the electrode 58 is no longer touching the wire 60 current is conducted to the wire 60 from the electrode 58 through the plasma 64. Again, when the train 50 slows below some speed, such as 60 miles an hour, then the control 56 may move the pantograph 52 up so that the electrode 58 again contacts the wire 60. Thus, two objects are achieved: conduction is therefore achieved at very high speeds through plasma, without the problems referred to hereinbefore; conduction is also achieved at low speeds, through conventional means, without the problem of possibly burning up the catenary wire 60 which could result if a constant flow of plasma were directed at a single length of the line 60, or at too slow a rate along the line 60 (such as when starting up under high currents). Conduction from the catenary wire 60 to the motors within the train 50 may be made through the pantograph 52 as is well-known in the prior art. Conduction from the electrode 58 into the pantograph 52 may be made through suitable bearings, as described with respect to FIG. 5 hereinafter. Thus, the plasma 64 is used at higher speeds to complete the conduction from the catenary wire 60 through the pantograph 52 and the train 50 to ground, such as rails 66,

and return through the power source 68, as is known in the art.

Referring now to FIGS. and 6, the electrode 58 may comprise a drum 70 which includes an outer peripheral portion jointed to a shaft 72 by web structures 74. In the embodiment shown in FIGS. 5 and 6, the web structures 74 are rigidly mounted to the shaft 72, and the shaft 72 turns with the drum 70. The shaft 72 may be journalled in a bearing assembly or pillow block 76 which may in turn be suitably mounted to a frame 78 which is pivotably disposed on the pantograph 52. The bearing assembly or pillow block 76 includes a sealed ball bearing structure (of which there are plethora known in the prior art) having a valved entry nipple 80 through which mercury may be injected into the sealed area of the bearing race 82. The provision of a sealed bearing containing mercury gives a wide area of metallic conduction through which current flowing into the drum 58 from the plasma 64 may flow to reach the frame 78, and eventually pass to the pantograph 52. As is known in the prior art, current may be conducted from the frame 78 to members of the pantograph 52 through a strap 84, thereby bypassing the pivoting joints 86 between the frame 78 and the pantograph 52. On the other hand, any suitable conduction from the frame 7 8 to the pantograph may be made in accordance with the teachings of the prior art.

Disposed at either end of the drum 70 are a plurality of vanes 88. These vanes cause the drum 70 to turn in response to the relative motion of the electrode 58 with respect to the atmosphere. In other words, a common pinwheel type effect can be utilized to cause the drum to rotate continuously whenever a plasma 64 has been struck provided train is moving. This provides a new relatively cool metal surface to the area where the plasma 64 impinges on the drum 70 beneath the catenary 60, which eliminates hot spots and therefore eroding of the metal of the drum 70.

The drum 70 on the other hand may be suitably driven by electric motors or in any other fashtion, to suit the particular implementation of the present invention.

The drum 70 may be several feet long so that as the train proceeds underneath the catenary 60, any variation in alignment between the centerline of the train and the position of the catenary wire 60 will not prevent the drum 70 from being adjacent to the catenary 60. Also, as the train rocks back and forth proceeding down the track, some portion of the drum 70 will be immediately adjacent the catenary 60 so as to permit the contact therewith at low speed and a plasma flow therebetween at high speeds. The particular size and shape of the electrode 58 may be varied to suit the given implementation utilizing the present invention.

According to another aspect of the present invention, any one of a variety of low ionizing metal may be embedded in the surface of the drum 70, as indicated by the stippling at reference 90. Such metals may comprise any of the alkali metals such as:

Alkali metals Cesium Lithium Alkaline earths Sodium Barium oxide Potassium Calcium oxide Rubidium Strontium oxide The moving vehicle embodiment of the invention is described with respect to a catenary wire. However, the invention is equally advantageous in third-rail systems.

Although the invention has been shown and described with respect to preferred embodiments thereof, it should be understood by those skilled in the art that the foregoing and other changes and omissions in the form and detail thereof may be made therein without departing from the spirit and scope of the invention, which is to be limited and defined only as set forth in the following claims.

Having thus described typical embodiments of the invention, that which we claim as new and desire to secure by Letters Patent of the United States is:

1. In a vehicle having a pantograph or the like mounting an electrode adapted for conduction of electrical currents to or from a catenary wire, the combination comprising:

an electrode including a conducting surface having a dimension extending transversely with respect to the catenary wire;

positioning means including means for sensing the relative positions of said surface and the catenary wire and means responsive thereto for positioning said surface in proximity with the wire but separated therefrom by a gap suitable for plasma conduction therebetween; and

means for providing motion of said surface in a direction parallel with the wire.

2. The system according to claim 1 wherein said electrode includes aerodynamic vanes disposed on an end thereof and oriented so that motion of the vehicle relative to the atmosphere acting upon said vanes will cause rotation of said electrode.

References Cited UNITED STATES PATENTS Re. 25,088 11/1961 Ducati et a1. 219-121 X 873,668 12/1907 Janin 191-56 1,089,142 3/1914 Mattman 310-240 1,553,728 9/1925 Sjobring et al. 219-84 1,930,933 10/1933 Hartmann 310-219 2,459,841 1/ 1949 Rouse 313-346 3,158,727 11/1964 Woelz 219- 3,233,849 2/1966 Rubin 152-353 X 758,355 4/1904 Fletcher et a1 191-61 ARTHUR L. LA POINT, Primary Examiner G. H. LIBMAN, Assistant Examiner U.S. Cl. X.R. 313-346, 339-5

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