US2046374A

US2046374A - Electrostatic bypass member

Info

Publication number: US2046374A
Application number: US717284A
Authority: US
Inventors: Foerste William
Original assignee: PACKARD PROPERTIES Inc
Current assignee: PACKARD PROPERTIES Inc
Priority date: 1934-03-24
Filing date: 1934-03-24
Publication date: 1936-07-07
Anticipated expiration: 1953-07-07

Description

July 7, 1936.

W. FOERSTE ELECTROSTATIC BYPASS MEMBER Filed March 24, 1954 'Ol'OOOOOOO' OOO'OIOO'O INVENTOR W/LL/AM FOERSTE I I I ATTORNEY Patented July 7, 1936 UNITED STATES PATENT OFFICE ELECTROSTATIC BYPASS MEIWBER of New York Application March 24, 1934, Serial No. 717,284

4 Claims.

The invention relates to by-pass members suitable for use in restoring to operation, for example,

the remainder of a bank of neon lamps after one or more lamps thereof have become inoperative, and also to protect transformer apparatus against possible excessive voltages under open circuit conditions of its secondary.

Various eXpedients have been proposed to meet these contingencies; and it is an object of the present invention to provide a simple, effective and relatively inexpensive member operating electrostatically, when these abnormal conditions obtain, to shunt or by-pass the defective element or portion subjected to excessive potential.

A further object of the invention resides in the provision of a member of this nature which will admit of being readily restored, either manually or automatically, to its normal-.state upon correction of the abnormal condition.

In carrying out the invention, an evacuated vessel is provided with two electrodes whose one pair of ends extend outwardly through the vessel for external connection while the other pair of ends are yieldable and juxtaposed, but separated sufficiently so as to be attracted only when abnormal voltage conditions prevail. This attraction, under excessive impressed voltages, will cause the yieldable free ends to move into contact with incandescence of the said wire ends and their welding together upon actual contact. The weld may be regulated to be only over an extremely small area so as to lend itself readily to separation and the restoration of the by-pass member to its original state, when the abnormal conditions are removed, as by a slight mechanical tap or blow directly upon the vessel or, as a matter of fact, upon any mechanically connected part. Furthermore, the said juxtaposed ends are caused to overlap slightly and may be helically coiled so as to obviate undesired breaking of the weld through flexing thereof upon cooling.

The nature of the invention, however, will best be understood when described in connection with the accompanying drawing, in which:

Fig. 1 is a more or less diagrammatic view illustrating the application of the novel by-pass member to a neon lamp lighting system; and Fig. 2 is a similar view illustrating a modification.

Fig. 3 is an enlarged view, in elevation, illustrating the novel by-pass member.

Referring to the drawing, more particularly Fig. 3 thereof, I0 designates an evacuated vessel, as a glass tube, the evacuation having been carried to such an extent as to provide for extremely high vacuum or a hard tube. Extending through the opposite ends of this tube are rigid metal electrode members H and I2 affording the terminals l3 and M, respectively, exteriorly of the tube for impressing voltage upon said electrodes.

The respective inner extremities l5 and I6 of these electrodes are yieldable or more or less flexible and may consist of separate wires and of a material such as tungsten, Nichrome, carbon, etc. This yielding property may be attained by providing them in the nature of the helically coiled portion shown, and the convolutions being of a diameter, for example, of .003 to .005".

Moreover, these ends l5 and B6 are juxtaposed, overlapping each other to a slight extent, say .075, and are also separated normally a very slight amount, the separation being of the order of magnitude of .050. These particular dimensions are, of course, subject to variation in accordance with conditions of operation. 2

Furthermore, it has been found desirable to so proportion these electrode extremities, as to weight or volume or both, that their natural periods of vibration shall differ appreciably from the frequency of any applied voltage or other disturbing influences and in order that they may not be tuned mechanically to a state to be set into vibration or actuation other than through the electrostatic attractions developed between the said cooperating electrodes.

Such attraction will be determined only by the abnormal conditions which it is the purpose of the by-pass member to protect against; and it is a function of the magnitude of the separation, degree of flexibility of the ends and the extent of their overlap.

The practical application of this novel by-pass member is indicated in Fig. 1 of the drawing wherein the secondary 20, of the usual magnetic leakage type transformer mounted in the casing 2|, is connected to the

terminals

22 and 23 of a neon lamp bank comprising the individual letters 24, 25, 26 and 21. Provision is made to ground to the lamp bank casing (not shown) and through a by-pass member 30 one or the other half of the halves of the lamp bank should failure occur therein. Thus, if a leak or crack should develop in the section comprising the lamps 24 and 25, the voltage on the remaining section would become overbalanced and the grounded bypass member 30 caused to function together with a similar by-pass member 3| connected to the midpoint 32 of the secondary of the transformer and grounded, for example, to the casing 2| thereof. This will leave the remaining sections,

comprising the lamps 26 and 2'6, illuminated and operative.

At the same time, the end portion of the secondary 28 of the transformer corresponding to the darkened lamps will be operating on open circuit and will set up an excessive voltage across a further by-pass member 33 which is connected between the terminal at this end of the secondary and the grounding casing 2| of the transformer, so that this open circuit becomes closed and excessive voltage upon the secondary coil portion is avoided. Similarly, a by-pass mem-- ber 34 connected between the opposite terminal of the secondary 2S and the casing 25 of the transformer will protect this particular end portion of the secondary in the event that the opposite section of the lamp bank, and comprising the letters 24 and 25, should remain operative and the letters 26 and 2? become inoperative.

In Fig. 2, the secondary 40 of the transformer, in casing GE, is shown connected as in the previous embodiment to the opposite terminals 42 and d3 of a lamp bank of individual letters 44, 65, it and it; but in this instance each individual letter is protected by a by-

pass element

48, 9, 50 and 5:, respectively, and no ground connection provided for secondary 36. In this embodiment, the novel by-pass element wiil shortcircuit, through the momentary high vol developed, an individual letter in the event of failure thereof, by-passing the said letter and permitting the remaining ones to remain illuminated. By this expedient, the voltage developed in the transformer secondary at is then reduced rather than increased. This is highly desirable as well as the fact that the by-pass members, having once been tripped, will remain so until restored and will therefore not be effected by any switching on or off of the sign as a whole, as in the case of flashing signs. The transformer and wiring voltages, therefore, will always be kept within their safe rating.

This property of the inner terminals of the lay-pass member to weld together under predetermined electrostatic conditions and maintain thereby a by-pass condition renders the protection permanent, and until again restored when the conditions have been corrected; and by constructing the said inner ends of the electrodes to be of a flexible nature, the permanency of the weld is insured as the cooling of the juncture and electrodes after welding will not cause flexing of the latter to an extent suificient to break the weld.

However, should it be desirable to provide for an automatic restoring action, the cooperating by-pass member for connection across a high voltage circuit, comprising a pair of normally separated relatively movable electrodes approaching each other solely in response to the electrostatic influence afforded by the circuit and of mass adapted upon contacting of the electrodes to weld the same together, and a vessel enveloping the electrodes and evacuated to a degree preventing arcing and ionization in the space between electrodes, the latter affording terminals externally of the vessel.

3. An electrostatic, removable circuit-closing by-pass member for connection across a high voltage circuit, comprising a pair of normally separated relatively movable electrodes approaching each other solely in response to the electro static influence afforded by the circuit and of mass adapted upon contacting of the electrodes to weld the same together, the said electrodes at their free ends being constructed to accommodate the effects of temperature changes so as to maintain the weld, and a vessel enveloping the electrodes and evacuated to a degree preventing arcing and ionization in the space between electrodes, the latter affording terminals externally of the vessel.

4. An electrostatic, removable circuit-closing by-pass member for connection across a high voltage circuit, comprising a pair of normally separated relatively movable electrodes approach ing each other solely in response to the electrostatic influence afforded by the circuit and of mass adapted upon contacting of the electrodes to weld the same together, the said electrodes having helically coiled free ends to maintain the weld. and a vessel enveloping the electrodes and evacuated to a degree preventing arcing and ionization in the space between electrodes, the latter affording terminals externally of the vessel.

WILLIAM FOERSTE.