US1740494A - Hot-filament rectifier - Google Patents

Description

Dec. 24, 1929, E. w. BREISCH 0,

HOT FILAMENT RECTIFIER Original Filed Nov. 5. 1920 I 6 I 7 i; 47 I AZ J9 /0 WlTNES SES: {NVENTOR 4.66 44M fi/yzr W fira/sz W BY MW W.

ATTORNEY Patented Dec. 24, 1929 UNITED STATES PATENT. OFFICE EDGAR W. BREIS CH, OE EDGE'WOOD, PENN SYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC 8t MANUFACTURING COMPI sNY, A CORPORATION PENNSYLVANIA I Ho'r-rILAMEn'r RECTIFIER Application filed November 5, 1920, Serial No. 422,019. Renewed October 11, 1923.

- This invention relates to hot-filament rectifiers and, in particular, to means for increasing the rating and the life of such rectifiers. I

In the operation of a hot-filamentrectifier bulb, the current passes from the bulb anode to the filament and then, combining with the filament current, increases thetemp'erature of the filament. As the filament temperature determines the rating of the bulb, any method which will allow a greater rectified'current Without an increased heating of the filament will increase the capacity of the bulb or give a longer life at the same rating.

My invention relates particularly to filamentary rectifiers of the type wherein the 'fila- 'ment temperature tends 'to follow the wave form of the current traversing the filament. Where the filament of the rectifier is ener- 2 gized from a small auxiliary-coil on an alternating current transformer, and the load current is in phase with the heating current, the load current passes from'the anode to the filament and there combines with the filament I current to increase the temperature of the filament, particularly at the peak of the current wave.

The main object of my invention, therefore,

is to provide means whereby the rectified our- 30 rent and the filament current may be so dis: placedin time-phasethat, when the rectified current is maximum thefilament current is minimum. This may be done by means of an internal reactance 1n the transformer, or

35 by a separatereactance, so adjusted as to give the proper phase angle.

The single figure of the drawing is a sche-Y matic diagram of connections, showing a pre ferred form of transformer;

o i The alternating-current supply -is fed throu h leads 1 and 2 to the primary coils 3, 3 o a transformer 4. The secondary coils 5,5 are connected together and a mldpoint 6 of such connection is connected to the negative terminal of the battery7.'. The coils 5, 5 have their outer terminals 7 and 8 connected respectively, to the anodes 9 and 10 of the bulbs 11 and 12. The filaments 13, 13 of the bulbs are energized, respectively, from auxillo iary coils- 15, 15 of the "transformer. The

positiveterminal of the battery 7' is connect: ed to the filaments 13,13 through a junction point 14 that. connected also to the common terminal 16 of the coils 15, 15. The C0llS 5, 5 and 3, 3 may be separatedby ducting material. As shown, the auxiliary coils 15 are wound over the primary coils 3 in order to ensure good regulation therein,

In operation, the charging current for the 155 means of washers 17 of any suitable non-con- I battery? divides between thesecondary coils 5, 5 and the bulbs 11, 12, as iswell understood. That is, during one half cycle, when the terminal? is positive, the current flows through bulb 11 to the positive terminalof the battery 7 and thence backto thelneutral point 6 of. the secondary. In like manner;

when the tei'1'nina'l18 is positive'thecurrent flows through bulb 12 to the positivetermisecondary winding '5-on a portion of the I transformer core, which is separated from the primary winding 3 by a considerable in- I tervening space and by the, non-magnetic spacers 17, a substantial e to intervene between the primary and load secondary windings. Asa well-known con-g comltant of such a leakage flux" between transformer windin s, an internal impedance effect is produced w ereby the secondary has i a phase displacement with. respect to the primary, the amount of displacement being dependent upon load current in the secondary. Since the filament-heating current is very nearly in phase with the primary current, it will be seen that the rectified current passing from anode'to filament will not reach its maximum or peak value at the same time as the heating current of the filament. In this manner, the filament may be made from a I much finer wire than in other designs.

There are various ways of obtaining the desired result, with the reactance either internal or external to the transformer, and

my invention is not to be construed as being limited to the exact construction shown.

I claim as my invention "1L The combinatiomwith a transformer comprising a. primary winding, a main secondar Winding and an auxiliary second- My Win ing, of a filamentary rectifier bulb 'having its filament connected to said a'uX- iliary Winding and its oad circuit-connected" I to said main secondar winding, and meansfor providing a path r'considerably more leakage between said piimary Winding and said main secondary Winding than between said. primary Winding and said auxiliary winding 2. The combination with a rectifyingde Vice having a heated filament, of a' transformer comprising acore having t'woserially connected magnetizable portions'and'means for providing aleakage flux between said-1 portions, coils .on both of said portions, a

supply circuitfc'onnected across coils mainly on one of said portions, a filament-energizing circuit connected across coils superposed on said last mentioned .coils and a load circuit 4 including said rectifying device and' con- 2a nected across -coils -mainly on the other of;

' said portions. v

' 3. The combination with an electrical-discharge device havinga heated cathode and an anode, of a transformer comprising a core havingtwo serially-related magnetizableportions' and means "for providing a'leakage flux between-saidportions,coils on both. of said portions, a load circuit includingisaidanode and cathode and, connected acrosswindings on one of said portions,- a filament-energizing circuit connected across windings on the other i of said'portions, and a. suppl circuit connected'across 'windings'on the latter portion. 4. In combination with an electrical-dis.

1 no charge device having "afcathode adapted to be-heated and an anode a supply transformer fhaving'ai r'irnaryw'indmg, a secondary windping close y coupled magnetically with said primary for he'ating said cathode and another 4 secondary,windingsubstantially less closely .coupled flmagnetically with said primary winding for'producin current flow between said anode and-catho e.' i. v I 3 y In testimony whereof, I have hereunto subscribed my name this 27th day o-f October;

v1920. EDGAR W. BREISGH;

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