US1656381A

US1656381A - Adjustable-core transformer

Info

Publication number: US1656381A
Application number: US643543A
Authority: US
Inventors: Orin E Marvel
Original assignee: DAY FAN ELECTRIC Co
Current assignee: DAY FAN ELECTRIC Co; DAY-FAN ELECTRIC Co
Priority date: 1923-06-05
Filing date: 1923-06-05
Publication date: 1928-01-17
Anticipated expiration: 1945-01-17

Description

Jan. 17,1928. 1,656,381

O. E. MARVEL ADJUSTABLE GORE TRANSFORMER Filed June 5, 1923 2f f' ff.

6 /4 INVENTOR,

44; ATTORNEY;n

Uff

Patented Jan. 17, 1928.

UNITED STATES 1,656,381 PATENT OFFICE.

GRIN' E. MARVEL, 0F

Y PANY,

DAYTON, OHIO, ASSIGNOR T THE DAY-FAN ELECTRIC COM- OF DAYTON, OHIO, A CORPORATION OF OHIO.

ADJUSTABLE-CORE TBANSFOBMER.

Application med Inne S, 1923. Serial No. 643,543.

This invention relates to a device for the transferoof high frequency electrical energy from one circuit to another as from the late circuit of a. vacuum tube to the gri or 6 control circuit of the followin tube.

It is one of the rineipal o jects of my invention to provi e a transformer with variable inductance and` impedance, so that the transformer will transfer this hi frequency energy at its maximum e ciency over a band of frequencies. The band of fr uen'cies that the transformer will cover isedetermined by the number of turns of wire of the primary and secondary windings andthe iron core. The ltransfer of energy of thetransformer with a given number of turns in the primary and secondary windin band of frequencies, amount of the iron core that links in the path of the magnetic flux set up by the cur-V rent flowing through the primary and secondary windings of the transformer.

y It is another object of my invention to provide a means of actuating the movable iron core in such a manner that it will change the inductance and impedance of the transformer over the band of frequencies for which the transformer may be designed. It is another pur cse of my invention to provide a means of eeping the potential of the iron core at zero with respect to the negative or common side of the electrical circuits.

It is still another object of my invention to provide a means of accelerating the dissiation of the electrical charge of the capacity of the primar and secondary windings, upon the reversa of the cycle of the electrical ener which is being transferred from one circuit to another.

It is a further object of my invention to provide a method of winding the rimary and secondary coils so that they wil have a smalldistributed capacity between their ends and the proper amount of capacity between the rimary and' secondary windings for an efiicient transfer of high frequency energy over a given band of fre uencies.

In the accom anying crawings, Figure 4is a longitudina sectional view of my transformer, taken on the line 1-1 of Figure 3. Figure 2 is-a side elevational view of the same, partly in section, illustrating diagrammatically the method of winding the priefficiency of the and iron core for a given' will depend upon the mary and secondary wires. Firure 3 is a cross sectional view taken through the transformer on the line 3-3 of Figure 1. And Fig. 4 is a schematic diagram illustrating one application of my transformer.

Throughout the specification and drawings, similar reference characters'denote corresponding parts.

In the accompanying drawings illustrating one form of embodiment of my invention, the numeral 1 designates an elongated cylindrical lcasing made of non-conductive electrical material such as bakelite or special radio fiber.

Formed on the rear end of the casing 1 is an annular Harige 2, and on its middle portion there is an integral annular flange 3. Between these flanges the casing 1 forms a bobbin to receive a primary winding 4 and a. secondary winding 5. The primary winding 4 is connected between 'binding posts 6 and 7 on the

flanges

2 and 3 respectively, while the secondary `winding is connected between binding posts 8 and 9 on the same flanges. (See Figure 2.) These windings are layer Wound on the casing 1, without doubling back on any turn. This method of winding gives a small distributed capacity and the proper amount of capacity between the primary and secondary windings for an efficient transfer of high frequency energy over a given band of frequencies.

Longtudinally movable into and out of the wound part of the casing 1, is a nonmagnetic split sleeve 10 preferably of cop er whose interior is lined with suitable insuliting material 11 which surrounds a laminated core 12 made up of very thin strips of high frequency iron. (See Figure 3.)

Suitably secured to the front end of the sleeve 10, for the purpose of moving it longitudinally within the casing 1, is a rod 13 which carries on its front end a knurled knob 14. This rod is calibrated for desired wave lengths by having provided on its rear portion graduations 15 corresponding to those wave lengths. A desired wave length Vmay be readily selected by moving the rod to a position wherein a graduation 15 desig nating that wave length is in alinement with the front end of the casing 1. The rod 13 thus provides 'a selective and convenient means for changing the position of the iron core containing-sleeve 10 within the wound part of the casing 1 to change the inductance 11 andim dance of the transformer over the l band 'o fre uencies for which it is designed,

v radial hole which extends through the casing 1, to receive a screw 16 whose inner portion is hollow to contain a helical spring 17 which pressesa carbon brush 18 intoengagement with the iron core containing-sleeve 10. A wire 19 connects the screw 16 with thesecondary wire so that the brush 18 will ground the sleeve 10, thereby'tending to Iilntaintaiiithe sleeve and secondary filament u i for radio purposes The urpose of this is to accelerate the dissi ation of the electricalcharge of the capaci y of the primaryand secondary windings, upon the ref vers'al of the cycle of the electrical energy bein Atransferred Ifrom one circuit to another. dapted to be slipped over the flanges-2,- and 3, behind a fronti-lange 20 on the casing l, is a cap or shell 21 to cover the primary and secondary windings. This cap ma be readily ap hed and removed.

salready sta the present invention relates primarily to the transferlof high fre-V quency electrical energy from one circuit to another, and is particularly applicable for use 4in airadio reiver,i orflike apparatus, ein loying vacuum tubes for amplifying hig frequency energy oscillations. In such apparatus high frequency energy oscillations are transferred from the plate or output circuit of one vacuum tube to the grid or in ut circuit of the next succeeding vacuum tu said circuits being coupled in energy transmitting relation with one another. Such coupling may be effected by means of the transformer herein described, the rimary winding 4 being connected in the ate circuit of the first' vacuum tube an the secondary winding 5 being connected in the 'grid circuit of the second vacuum tube. The connection of the transformer in such energy4 transferring relationship between the late and grid circuits asfjust describedis illustrated inthe schematic diagram of Fi 4 which shows the conventional and we arrangement of circuits for connect-4 ing one vacuum tubel with the next v`succeeding vacuum tube. 31. `1n this.arrange ment, the plate circuit 320i the first vacuum winding 4 o w ich is iii the plate circuit 82 [the tube 31 .thro h the seconda tube 30 is cou lcd with the input or grid: circuit 33 of c second vacuum tube 31 in the 4usual wa `b a transformer, the primary 4and the secondary windiizi 5 of which is in circuit 33,'whi latter circuit, it

the 'd willgobserved, extends from the grid of windn 5 to thelament o the tube 31'. at portion .of the grid circuit 33 which is between the ,up

5 andthe-filamentof the tube 31 und potential when the transformer is -is changed rom which it follows that is, because of its interrelation with other circuits not herein illustrated, commonly said to be on the negative or common side of the circuit. The sleeve 10 of the transformer is connected with or ounded to that terminal of the secondary winding,` 5 which lis connected to the negative or common side of the circuit and hence the sleeve is at the same potential as this side of the circuit.

Iii the operation o f an apparatus as described, when it is desired to transmit oscillations of itV iven frequency or wave length from the pliite circuit 32 to the grid circuit 33, the iron core 12 of the transformer. is moved to the position which will insure the most effective transfer of iener from the primary winding 4 to the secon ary winding 5, the proper position for the core being indicated by the calibrations on the stem 13.

lVlien it is desired to transmit oscillations of a different frequency the position of the core 12 is changed in accordance with the calibrations 4on the stem 13 so as to again obtain the most elective transfer of theenergy. By adjusting the iron core in this mannepthe amount-of iron that links with the magnetic` fields of the rimary and secondary windin e inductance and impedance of these windings also change with the position ofthe iron core' within'the windings. FromV the foregoing it will be ap arent that the movement o the core 12 within the windings results not only in a variation of the impedances of the windings but also in a simu taneous .varia tion of the impedances of the plate'and grid circuits in which they are connected, and hence the movement ofthe iron core constitutes a simple means for tuning these circuits for the most effective and eilicient transfer of energy between them. The p ose of splitting the copper sleeve 10 as s own in the drawin is to, prevent the formation of undesirab e eddy currents which tend to neutralize the action of the windings and to hinder the proper transfer of energy between the windings. Another advanta e of the resent invention is that it rovi es means or effecting sharp o 'the apparatus 1. A transformer comprising a casing, a primary and a secondary surround. ing the latter, a non-nagnetic split lsleeve movable in said casing, an iron core within gie sleeve, and means for vgrounding said4 2. A transformer comprising a hollow bobbin formed of insulating material, ri-

mary and seconV '.win diy in inductivel eoupl relatie with one another a ut said jbohb' 'an means for manually changing the in uctance and impedante of the transformer, said means disposed bobbin comprising mag-- netic means magnetically coupled with both of said windin non-magnetic conducting means dispose to have capacity coupling with both of said windings, and means for grounding said non-magnetic means.

3. A transformer comprising a casing, a

rimary and asecondary winding surrounding the latter, a non-magnetic sleeve movable in said casing, a brush in contact with the sleeve, a housing in said casing for the brush, and a wire connected between said housing and the secondary winding for 'the purpose specified.

4, A transformer comprising a casing,l a primary and a secondary winding surroundtlie latter, a non-magnetic sleeve movab e in said casing, said casing containing a radial hole, a hollow screw in the latter,a helical spring contained within said screw, a 4brush also in said screw adapted to. be forced into engagement with the sleeve by the spring, and a wire connected between said screw and the secondary winding for the purpose specified.

5. Av transformer oomprisin concentrically disposed primary and secon ar windings a non-magnetic sleeve disposed a jacent said windings and longitudinally movable relative thereto, and conducting means connected between said sleeve and one of said windings, to ground the former.

6. A transformer adapted to receive high frequency oscillations of varying frequencies, comprising a primary winding, a secondary winding inductively coupled with said rimary windin and supported fixed relation thereto, an means or varying the inductive relation ofi said windings to ac` cord with the frequent4 of the oscillations received, said means in uding a member of magnetiiniblev material mounted for movemember movable in the magnetic field of said windings, and means independent of said iron member foraccelerating the dis sipation of the Velectrical ca acity charge upon the primary and secon ary windings upon reversal of cycle of the electrical ener impressed upon the transformer.

8 anapparatus of the character de scribed, a hig frequency transformer adapted to receive high frequency oscillations of varymg frequencies, having-a rima winding,l a secondary winding in uctive y coiipled with said primary winding, and an iron member movable in the magnetic fields of Said windings for varyin the inductive properties thereof, said win ings comprising concentrically disposed coextensive coils each consisting of a single la er of wire4 whereby to provide small distri uted capacity between the ends thereof.

Intestimony whereof I have hereunto set my hand this 4th day of June, 1923.

ORIN E. MARVEL.

CERTIFICATE 0F CORRECTION.

filent No. 1,656,381. Granted January 17, 1928, to

ORIN E. MARVEL.

It le hereby certified that error appears in the printed specification of the above mmberved patent requiring correction as follows: Page 2, lines 129 and 130, elaim'Z, strike out the words,"disposed within said bobbin" and insert the lame to follow alter the word "means" in line l, page 3, of the same claim; and that the nid Letters Patent should be read with this correction therein that the same miy conform to the record of the case in the Patent Oiiice.

Signed and sealed this 14th day ol Fehrnlry, A. D. 1928.

M. J. Moore, Seal. Acting Conmissioner of Patents.