US1690566A - Current-ballasting device - Google Patents

Description

Nov. 6, 1928.

A. W. ZIEGLER CURREN'J. BALLASTING DEVICE Filed O t. 1925 A /2 l w 7 @7 hue/#0? Arf/wr H. Z/y/er by Patented Nov. 6, 1928.

UNITED STATES PATENT OFFICE.

ARTHUR WILLIAM ZIEGLER, OF SOUTH ORANGE, NEW JERSEY, ASSIGNOR TO WEST- ERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y.. A CORPORATION Q1 NEW YORK.

CURRENT-BALLASTING DEVICE.

' Application filed October 5, 1925. Serial No. 60,476.

This invention relates to current ballasting devices and has particular application to the type employing an iron wire resistance element.

It has for an object to provide a current ballasting device which is easily constructed, possesses long life and operates efficiently over a wide rangeof voltages.

In the operation of a plurality of vacuum tubes it is usually customary to employ a single source of potential to supply heating current to all the filaments of said tubes. In many cases in such operations, it is desirable to regulate the heating current supplied very closely and current ballasting devices may then be connected in series with a source of potential for this purpose. One type of current ballasting or regulating device which has been heretofore employed is the iron wire ballast lamp comprising an iron wire resistance mounted in a chamber containing an inert gas, such as hydrogen. A discussion of the theory and uses of such a ballastiiig vice may be had from an article by A. Jones in the General Electric Review for Ma 1925 page 329.

uch devices, however, have a limited voltage range of effective or efiicient operation and when operating over their maximum effective range require greater care in their manufacture than .is suited for economical commercial production. Furthermore, the life of this type of ballast device has been found to depend substantially upon the temperature at which it operates or upon the voltage impressed upon it, and decreases rapidly as the operating voltage approaches the maximum efiective voltage.

A feature of the invention comprises a ballast lamp of the iron wire resistance type having two or more filaments adapted to be connected in series and shunts for normally shunting a predetermined number of said filaments and means for opening the shunt across one of said filaments when the voltage impressed upon the device exceeds the effective voltage of the filament in operation. Such a device may be connected for example in series with the source of heating currents for vacuum tube filaments to regulate the filament current within narrow .lirnits over a wide range of voltages.

Another feature of the invention is the use of a plurality of single filament lamps in place of multiple filaments in a single lamp as described above.

A fuller understanding of the invention will be had from the more detailed description to be given in connection with the accompanying drawings in which the same reference characters represent similar parts.

Fig. 1 shows a ballasting device comprising a multiple filament ballast lamp in accordance with one feature of the invention connected so as to regulate the filament current of a plurality of vacuum tubes connected in tandem.

Fig. 2 shows the manner in which the plurality of single filament ballast lamps may be connected to operate in place of the multiple filament lamp of Fig. 1.

Referring to Fig. 1 of the drawings, a plurality of vacuum tubes 1 comprising anodes 2, control electrodes 3, cathodes 4 are shown connected in tandem as is well understood in the art. Heating current is supplied to the cathodes 4 from a source of potential 5, through a retard coil 6, a suitable t'use 7 and a current ballasting device. The retard coil 6 operates to eliminate noises by ofi'setting sudden fluctuations in the battery current. In accordance with the invention, the ballasting device may comprise a ballast lamp 8 having filaments 9 and 10 adapted to be connected in series in the filament heating circuit and a high-resistance marginal relay l1 and a shunt 12 normally placed across one filament, 10 for example. Relay 11 is designed to operate when the potential across the circuit exceeds the effective operating voltage of filament 9. \Vhen relay 11 operates it opens shunt 12 thereby connecting filaments 9 and 10 in series.

I'Vhen a multiple filament ballast lamp as described above is employed for the primary purpose of regulating the filament current within extremely narrow limits, the first filament as filament 9 is preferably made longer than the second filament as filament 10 so that the change in the ballasting filament temperature resulting when relay 11 operates is not such as to cause an appreciable change in the ballasted current.

Furthermore, it is known that the life of a ballast lamp filament is dependent primarily upon the temperature or voltage at which it operates and that the life is greatly shortened as the operating voltage approaches or exceeds the maximum of the effective range. In the arrangement according to this invention, therefore, the life is substantially ncreased and the tendency for the characteristics for a lamp to change decreased, since the filaments operate at temperatures or voltages appreciably below their individual e ective maxima.

In the arrangement of Fig. 2 a plurality of single filament ballast lamps 13 and'let are substituted for the multiple filament lamp 8. As in the first arrangement, a relay 11 is employed to place the lamps 13 and 14 in series when the applied potential difference exceeds the effective voltage of lamp 13 by attractlng its armature 12, which in its un'attracted position shunts lamp 1%.

The filaments of the multiple filament lamp or of the single filament lamps are composed of some metal having a positive temperature coefficient such as ure iron wire and are mounted in a cham er containing an inert atmosphere such as hydrogen. A suitable lamp for use over a voltage range of from 2- to 9 volts might be, for example, two filaments of pure iron wire approximately six centimeters long and .0096 centimeters in diameter, in an atmosphere of hydrogen under a pressure of 20 millimeters of mercury. As an example of a satisfactory lamp for use when it is desired to maintain current within extremely narrow limits, a lamp having its first filament 6 centimeters long and a second filament 3.8 centimeters long, both filaments being approximately .0096 centimeters in diameterin an atmosphere of hydrogen under a pressure of 15 millimeters of mercury may be used.

It will be evident that other suitable contact making devices, such as contact makin voltmeters, may be substituted satisfactorily for the marginal relay shown herein.

It is also evident that the methods of ballasting currents in accordance with the invention may be modified to include the use of more than two filaments in a single lamp or the use of any number of ballast lamps containing single filaments. Similarly, the relay or relays operating the shunt or shuntspart of the circuit where le; in some cases, therefore, a sin le relay or contact makin device with a mu tiplicity of contacts may fie preferable where more than two filaments or single filamentballast lamps are employed.

he arrangements of the present invention have been found to be rticularly adapted for use for current regu ation within narrow limits over a wide range of voltage as desired. Tests have shown, for example, that the device represented in Fig. 1 may be employed to maintain the current within a variation of 10% over a voltage variation greater than 800%; further, if only the most efiicient opmay be placed in any it may seem desira g increasing the range of effective changes in said circuit necting additional of said elements in series crating range of the device was considered, the current was found to be maintained with 1.7% over a potential change of 250%.

While the invention has been described herein with reference to a particular type of regulating device and to a particular type of circuit to be regulated, it will be that it is not intended to limit the invention to these applications alone, but that of the invention are susceptible of various adaptations and modifications within the scope of the ap 'nded claims.

The term e ective voltage is employed herein to define any voltage within the range of applied voltages over which the device will maintain the ballasted current substantially constant.

What is claimed is:

1. In combination, an electrical circuit, a source of potential for said circuit, a plurality of ballasting elements adapted to be connected in series in saidcircuit, one of said elements being normally connected in said circuit, means for increasing the range of effective ballasting, said means comprising means connected in parallel with said one element and acting in response to voltage changes in said circuit for connecting another of said elements in ment when the voltage across said circuit exceeds the effective ballasting range of the said one element.

2. In combination, an electrical circuit, a source of potential for said circuit, a ballasting arrangement, said arrangement comprising)a plurality of ballasting elements adapted to e connected in series in said circuit, each of said elements having a positive temperature coeflicient, and one of said elements being normally connected in said circuit, means for ballasting of said arrangement, said means comprising means connected in parallel with said one element and acting in response to voltage for successively conwith said one element when the voltage across said circuit exceeds the effective ballasting voltage of the ballasting means already in said circuit.

3. In combination, an electrical circuit, a source of potential for said circuit, an iron wire ballasting element comprising a plurality of iron wire filaments adapted to be connected in series with said source, one of said filaments being normally connected in said circuit, means connected in parallel with said one filament and changes in said circuit for connecting another of said filaments in series with said circuit when the voltage across said circuit exceeds the effective ballasting voltage of the said one filament.

4. In combination, a plurality of electron discharge devices, each of said devices havacting in response to voltage all features series with said one eleing an anode and a cathode, a source of potential for supplying heating current to said cathodes, a ballasting arrangement for regulating said heating current over a wide range of voltages, said arrangement comprising a plurality of iron wire icsistance ballasting elements adapted to be connected in series,

one of said elements being normally comiected in series with said source, and means for increasing the range of efiective ballastmg of said arrangement, said means connected in parallel with said one element and acting in response to voltage changes in said source for bringing additional of said elements into serious relation with said source when the voltage across said source exceeds the effective ballasting Volta, e of said one element.

In witness w ereof, I hereunto subscribe my name this 3rd da of October, A. D. 1925.

AR UR W. 'ZIEGLER.

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