US1579944A - Current-rectifying system - Google Patents

Description

April s, 1926, 1579,944

' J. JOHNSON CURRENT RECTIFYING SYSTEM Filed April 4, 1925 STEP UP STEPflOW/V INVENTOR.

' JOSfP/V JO/l/YSO/Y Y WW ATTORNEY.

tifying Systems, of which the following is a v Patented 6, 1926.

uNrr-eo] s-rA-Tes PATENT-T OFFICE.

Josnrn JOHNSON, or NEw YORK, N. Y.

ctrnnENT-Imonrnnc svszrnm.

To all whom it mayconcern:

Be .it known that I, JOSEPH York city, in the county of Bronx and State of New York, have invented certain newand useful Improvements in Current-Recfull, clear, and exact description.

My invention relates generally 'tosystems for modifyingelectric currents and relates particularly to current rectifying systems of the type adapted to rectify commercial al-' ternating current and then to modify the pulsatingrectified current for the purpose of providing an unpulsating or uniform direct current. 2 My invention relates" more particularly to such systems which are adapted for use in'connection with radio supplying current to the receiving sets for the electron tubes, and

plate circuits of commonly commercially known as B-battery eliminators,"although it is to be understood that the system of'my invention is adapted to other uses.

Heretofore such rectifying systems have not been entirely satisfactory. Commonly the direct current delivered thereby to the radio set has been sufiiciently pulsating or undulatory in character as to cause an objectionable' humin the telephones or loud speaker. Also commonly these systems have 7 been incapable of impressing a sufliciently high voltage upon the plates of the amplifying tubes for their most effective operation.

Also when,-as*occasionally occurs, there is I V a momentary 'var'iation'or drop 'in voltage in the commercial'currengcommo-nly these systems have passed on this variation or drop tdthe receiving set resultingsin a correspondinggfading wof-jthe signal; Furtherx -mo'i e',- these; rectifyingfsystems Ihave }com i -monlyibeen eomparatively GQmplieat'edQ h'aVB ally designed1 parts;g. and "eon;

I JoHivsoN, a citizen of the United States, residing at New e' suitable vjlfogmef 5 Application file d-lApril 4,1925. ser al 1%. 20,762. I

in constructionywhich embodies readily replaceable" standard parts, and which is inexpensive to manufacture." Other morepar ticular objects and advantages of my inven-- ti'on will hereinafter appear.

My invention includes features of construct-ion and combinations of parts as will appear from the following description. I

.I shall now describe the embodiment of my invention illustrated in the accompanyb u I ,I I my invention in claims.

- in drawing and shall thereafter point out The drawing is a diagrammatic representation of the operat ng parts and circuits of an embodiment of my invention.

As illustrated in the drawing, a pair of. terminals 1 and 2 are provided as means for establishing a connection to a commercial alternating current supply circuit. These terminals may be ord nary binding posts, or

any other convenient means'towhich a usual cord may be connected and two-wire plugged into an electriclight socket on wall socket. The'commercial alternating current to be supplied to the terminals .1- and 2 is most commonly 110 volts, at cycles per second, as indicated on the drawing; A pair of line conductors 3 and 4 lead from the respective terminals 1'. and '2 and are connected' to the ends of the primary 5 of a;

step-up transformer 6 having a double or' two-part secondary7 r The ends of-the'secondary'7 are respectively connected by conductors 8 and'9 to the plates of two rectifying tubes 10 and -11 of the heated filament type;' The voltageimpressedupon the plates of the rectifying tubes 10 and 11 lay-the step-up transformer v 6' maybe whatever desiredifor example,

volts; and}. in the particular-"apparatus :11- m a f h aw ngs-as. e o t e ys em Tdi my invehti f t a nag tively connected by conductors 17 and 18 to conductors 19 and 20' which connect together the filaments of the tubes 10 and 11, so that these filaments are thereby connected in parallel in an alternating current circuit. The step-down transformer 12' maybe of the standard commercial type known as a bell tubes without a filament such as sodion' tubes, commercially known as S tubes, cut down 'the plate circuit vhltage too much to be desirable as rectifying tubes in a B-battery eliminator.

A positive lead 21 for rectified current is connected'to one side of the filament circuit, for example, to one of the filament-connecting conductors 19 or 20, and is shown as connected to the conductor 20. The other or outer end of the positive lead 21 is connected to an output terminal 22, which may be a' binding post or other convenient means for making a connection to the raido set. A neg 'ative lead or return lead 23 for the direct rectified current isconnected at its outer end to a terminal 24; through which it may be conveniently connected to the radio set, and at its inner end the negative lead 23 is connected to the middle point of the double secondary 7 of the step-up transformer 6.

Current modifying means forming a feature of-my invention are provided for effectively changing the pulsating rectified current to a substantially uniform direct current, free from noise-producing pulsations or undulations, such-means also operating so as effectivelyv to eliminate momentary current" fluctuations, such as would cause a momentary fading, as will hereinafter appear. A reactor 25 is'connected in series in the negativelead 23, and two storage devices shown as electrolytic condensers 26 and 27 are connected in parallel across the leads '21 and 23, the connections of the negative sides or terminals of these condensers to the negative lead 23 being made at opposite sides of the reactor 25, separately for each-condenser, by means of independ.

ent conductors 28 and 29 respectively, while the other or positive terminals of the condensers are shown as respectively connected v to the positive lead 21 by means of separate conductors 30 and 31, although obviously the connection to the positive lead could as well be made by means ofa single conductorcommon to the two condensers if so desired.

The reactor 25 should have large induc: tance and is provided with an iron core, and the electrolytic condensers 26 and 27 are of large capacity. I have found an inductance of ten henries in the reactor 25 to be suitable, and electrolytic condensers such as 26 and 27 each having a capacity of twenty-eight inicrofarads have proved satisfactory. The reactor 25 may be of a readily pur'chasablecommercial type and, in fact, I have found that a bell transformer similar to the stepdown transformer 12, when suitably connected in the negative lead 23, serves the purpose very well. The electrolytic. condensers 26' and 27 may be of a commercial type and may, for example, be of'the general type of: that disclosed in the patent to Mershon, No. 1,141,402, dated June 1, 1915.

By reason of employing filament type rectifying tubes, such as 10 and'll, connected in the rectifying and filament-heating I circuits as hereinbefore described, in carrying out my invention, a suitable plate volta .third positive terminal 32 connected by a branch lead 33 to the main positive lead 21 beyond the last condenser connection 31 or adjacent the terminal 22, a variable resistor 34; being included in the branch lead 33. The voltage most commonly desired for the plate of the detector tube is about twentytwo and one-half volts, but this may be varied by means of the variable resistor 3et. The resistor 34 may conveniently be of the compression type, so as thereby, in-aresistor of small size, to'obtain a sufficiently high resist-ance together with ample range of vpltage adjustment, and this resistor may be of a standard commercial type.

' Electrolytic storage devices-such as the electrolytic condensers 26 and 27 perform a unique function and operate in a peculiarlyeflective manner in carrying out .my invention. Such condensers are comparatively small in size while at the same time they have very large capacity. Furthermore, and of particular importance in carrying out my invention, these condensers are comparatively slow acting in the sense that they will not completely discharge substantially instantaneously, but will retain a considerable portion of their charge which they deliver comparatively gradually over an a preciable periodof time. Therefore, asem died in my invention, such condensers are not conductors 3 and 4.. Under such circumstances the electrolytic condensers 26 and 27 deliver comparatively gradually a portion of their large charge, substantially in a manner similar to a'battery, and thus serve for the required short period of time as a source of current for effectively keeping upthe plate current and voltage, so that the volume of the reception in the receiving set is kept up without noticeable fading, such as commonly occurs. I

I have found it impracticable in carrying out my invention to make use of ordinary or non-electrolytic radio condensers, because, in order to obtain the large capacity I have found to be most effective, the size of such condensers and the space taken up thereby would be prohibitive; and also I have found that such condensers do not operate so effectively for my purpose and particularly they do not effectually eliminate momentary variations or fluctuations in the current,

probably because of their tendency to discharge, to whatever extent permitted, substantially instantaneously. 1

It is understood of course that the rectifying tubes 10 and 11 act alternately for rectifying both sides .of the alternating current wave, so as to produce a substantially uninterrupted pulsating direct current, as is well known in the use of two rectifying tubes.

However, I have found the operationof the current modifying means, including the reactor 25 and the electrolytic condensers 26 and 27, to be so effective that it is-pocsible to omit one of the rectifying tubes; and the above noted modifying means will effectively convert the intermittent direct rectified current into a current of such uniformity that no hum results in the receiver, and there is no noticeable decrease in volume. In such case I have noted that thesingle rectifying tube appears to do double duty and it will not last so long, and it is preferred to employ the two tubes 10 and 11 as hereinbefore described. 1

While electrolytic condensers have been shown and 'hereinbefore described as employed in the illustrated embodiment of my invention, it is to be understood that within the broader scope of my invention, other electrolytic storage devices, which need not necessarily be condensers, may be employed,

it being noted inthis connection that the polarity of the terminals of the condensers 26 and 27 is never changed. For example, suitable storage batteries might be employed. Also other forms of storage devices,

such as the well known aluminum electrolytic cells. However, I prefer to employ, as storage devices, electrolytic condensers, such as the condensers 26 and 27. These condensers not only operate very effectively for the purpose desired in my invention, but they require no attention whatsoever, emit no gases and do not,

overflow. Also such condensers of suitably large capacity are of comparatively small size, and they are of a standard, readily obtainable commercial type. It may be noted that in their commercial form these condensers are completely enclosed and not open at the top as shown diagramatically in the drawing, for the condensers 26 and 27.

The current rectifying and modifying system of my invention is adapted for use for any purpose where it is desired to obtain a uniform direct current from an alternating current source of supply. In using this system in connection with a radio set the terminals 22,- 32 and 24 are to be connected to the set in precisely the same manner .as a usual B-battery would be connected. The system of my invention is adapted to be used with the majority of the various types of radio receiving sets, for supplying B current to the plate circuits thereof.

It is to be noted that the system of my invention comprises relatively few parts of comparatively small size and that the circuit arrangement is simple. All of the several standard parts may be conveniently assembled and mounted and all circuit connections may be made by means of ordinary binding posts or other similarly. readily connecting and disconnecting means. All parts and circuits may be readily assembled into a compactself-contained apparatus, and such an assembly has been made upon a base board and "attached upright panel each seven by nine inches, which may be enclosed to form a box or cabinet, the entire apparatus occupying substantially no more space than a usual B-battery. If desired the entire system may .be built directly into the radio set asa feature thereof, thereby further economizing space.

It is obvious that various modifications,

changes in details, and variations in the arrangement of parts and connections, may be made in the systemshown lIl-tl1e drawing and above particularly described within the principle and. scope of my invention as pointed out in the appended claims. I claim:

11A current rectifying system comprising a. source of alterating current, a step-up transformer connected to said source, 8. rectifying tube of theheated filament type having its late connected to saidtransformer,v

a stepown transformer connected to said source, a filament-heating circuit including the step-down transformer, a positive lead for rectified current connected to the filament circuit, a negative lead 'for rectified current connected to the step-up transformer, a reactor connected in series in said negative lead, and two electrolytic storage devices connected across said leads in parallel and connected to the negative lead at opposite sides of the reactor.

2. A current rectifying system comprising a source of alternating current, a step-up transformer having a double secondary and having its primary connected to said source, two rectifying tubescof the heated filament type having their platesv connected respectivelyIto the ends of said secondary, a negative lead for rectified currel-t connected to the middle point of said secondary, a step,- down transformer connected to said source, a filament-heating circuit including the stepi down transformer and in which the filaments two electrolytic storage devices connected to the negative lead at opposite sides of the of said tubes are connected in parallel, a positive lead for rectified current connected to one side of the filament circuit, a reactor connected in series in said negative lead, and

across said leads in parallel and connezted reactor.

3. A current rectifying system comprising line conductors for commercial alternating current, a step-u transformer having its primary connects to said hne conductors, a rectifying tubeof the heated filament type havingits plate connected to the secondary of said' transformer, a negative lead for rectified current also connected to said secondary, a step-down transformer having its primary connected across said line conductors, a filament-heating circuit including the secondary of the step-down transformer, a positive lead for rectified cur.-

rent connected to the filament circuit, a reac tor connected in series in the negative lead,

and two electrolytic condensers connected in parallel across said leads and being connected respectively at opposite sides of the reactor in the negative'lead.

4. A current rectifying system'cornprising line conductors for commercial alternat-- ing current, a step-up transformer having 1ts primary connected to the hnec'onductors and aving a double secondary, two-rectifying tubes ofthe heated filament type one of which has its plate connected to one of the parts of'the double secondary andthe other of which has its plate connected to the other part of said secondary, a negative lead for rectified current connected .to the middle point of said secondary, a step-down transformer having its primary connected across the line conductors, a filament-heating.cir-

current, a step-u cuit including the secondary of the stepdown transformer and in which the filaments of the tubes are connected in parallel,

a positive lead for \rectified current con-' nected. to one side of the filament circuit,

' a reactor connected in series in the negative lead, and two electrolytic condensers connected in arallel across said leads and being respective y connected to the negative lea at opposite sides of the'reactor,

' 5. A current rectifying system comprising a source of alternating current, a rectifying device connected to said source, a lead for direct rectified current connected to said device, a return lead for the direct rectified current, a reactor connected in series in the negative lead, andtwo electrolytic storage devices connected in parallel across. said leads and being respectively connected to the negative lead at opposite sides of the reactor.

6. A current rectifying system comprising a source of alternating current, a rectifying device connected to said source, a positive lead for direct rectified current connected to said device, a negative return lead for the direct rectified current, a reactor connected in series in the negative lead, and two electrolytic condensers connected in parallel across said leads and being respectively con-- nected to the negative lead at opposite sides of the reactor. 7

7. A current rectifying system comprising line conductors for commercialalternating transformer having its primary connecte to the line conductors,- a

rectifying device connected to the secondary of said transformer, a positive lead for direct rectified current connected to said device, .a negative lead for direct rectified current connected to said secondary, a reactor connected in series in the negative lead, and-twoelectrolytic condensers connected in parallel across'said leads and bein respectively connected to the negative lead at'opposite sides of t he'reactor.

18. A system for modifying electriccurrents comprising a source .of direct currentvhaving positive and negative leads, a reactor connected inseries in one ofsaid leads, and two electrolytic storage devlces connected in parallel across said leads and being respectively connected to the reactor-containing JOSEPH JOHNSON.

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