US2277499A - Transformer - Google Patents

Transformer Download PDF

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Publication number
US2277499A
US2277499A US275782A US27578239A US2277499A US 2277499 A US2277499 A US 2277499A US 275782 A US275782 A US 275782A US 27578239 A US27578239 A US 27578239A US 2277499 A US2277499 A US 2277499A
Authority
US
United States
Prior art keywords
winding
transformer
windings
heating
frequency
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US275782A
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English (en)
Inventor
Missel Johan Cornelis Bastiaan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RCA Corp
Original Assignee
RCA Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by RCA Corp filed Critical RCA Corp
Application granted granted Critical
Publication of US2277499A publication Critical patent/US2277499A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
    • H04B1/1018—Means associated with receiver for limiting or suppressing noise or interference noise filters connected between the power supply and the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/1607—Supply circuits
    • H04B1/1623—Supply circuits using tubes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B15/00—Suppression or limitation of noise or interference
    • H04B15/005—Reducing noise, e.g. humm, from the supply

Definitions

  • the invention is based on the recognition that undesired disturbances reach the apparatus due to capacitative coupling of the intermediate-frequency amplifier and the mains-connection device and originate from the higher harmonics of the intermediate frequency which occur in theintermediate-frequency amplifier. If the anode vol tage winding of the supply transformer and the primary winding of this transformer are electrostatically screened from one another, the
  • hishe'rharmonics of the intermediate-frequency are substantially capacitatively transmitted to the heating circuits of the amplifying tubes and to the corresponding secondary winding and from the latter to the primary circuit of the .supply transformer and to the input circuit of the receiver and they consequently occur if the frequency of any one'of the higher harmonicssubstantially corresponds to the received frequency.
  • the interference phenomena are, particularly manifest in receivers in which a high intermediate frequency (e. g. 450 kilocycles per second) is utilised.
  • a high intermediate frequency e. g. 450 kilocycles per second
  • the said interference' is eliminated by electrostatically screening from one another not only the primary winding and the secondary winding which provides the anode voltage but also the secondary winding connected to the heating circuits of the amplifying tubes and the primary winding.
  • a metal foil e. g. a copper foil
  • a metal foil e. g. a copper foil
  • the secondary winding provided for heating the cathode of the anode voltage rectifying tube in such manner that it forms an electrostatic screen between the primary winding on the one hand and the secondary winding providing the anode voltages and the secondary nected to the heating circuits or, if there are more than two heating windings, all the heating windings between the primary winding of the supply transformer and the secondary winding which furnished the anode voltage.
  • the heating windings must of course always be arranged in such manner that the winding utilised for heating the rectifying tube, screens the primary windingfrom the other windings.
  • the screening winding should preferably be arranged, for the purpose of reducing the mutual capacity between the top ends of the coils, in such manher that it protrudes from the said ends.
  • the heating windings generally comprise only a small number of turns and require a smaller widthof winding than the other windings.
  • electrostatic screening should preferably be utilised in uch cases a single-layer coil, part of which serves to heat the cathode of the anodevoltage rectifying tube.
  • Fig. 1 represents the wiring diagram of the high-frequency portion of an ordinary superheterodyne receiver.
  • This portion comprises an aerial circuit I which is inductively coupled with an input band-pass filter 2, an oscillator circuit 3, a mixing tube 4 provided with a first intermediate-frequency band-pass filter 5 included in the anode circuit, an intermediate-frequency amplifying tube 6 and a second intermediatefrequency band-pass filter 1 whose output circuit is connected to a rectifying tube 20.
  • a mains-supply device of usual wiring which consists of a supply transformer 8 having a primary winding 9, a secondary winding ID for the supply of the anode voltage, a secondary winding H which is connected to the heating circuits of the amplifying tubes and a secondary winding it which serves to heat an anode voltage rectifying tube It and which is connected to a filter circuit l4 which serves to smooth the rectified current. Since the circuit-arrangement of the receiver and of the mains-supply device is substantially immaterial for the present invention it is not set out in detail.
  • the interfering voltages are transferred to the primary winding 9 whence they reach, generally by ca- I pacitative transmission IS, the input circuits I ll, connected to the I as faras possible without the transformer itself cies which become perceptible as an intzrference whistle noise.
  • the apparatus is not grounded or, as is frequently the case in practice, is not grounded in a faultless manner, i. e. that the resistance of the earth connection is not very small (shown in Fig. l as a resistance l9 represented by a dotted line), the interfering whistling noises become perceptible in a particularly unpleasant manner.
  • these interfering frequencies are elimi nated by screening from the primary winding 9 not only the secondary winding l0 but also the heating winding l I.
  • Fig. 2 represents a cross-sectional view of a convenient form of construction of a supply transformer 20 in which the above-mentioned windings 9, l0, and II are screened from one another by the use of the .winding I3 provided for the heating of the rectifying tube.
  • This winding itself covers, however, too small a wavelength and, in order to ensure satisfactory screening, it has been extended by dead windings :3.
  • a primary winding and a plurality of secondary windings In a power transformer assembly, a primary winding and a plurality of secondary windings. one of said secondary windings forming an electro static shield between the other secondary winding and the primary winding, said windings being concentrically arranged about one another, said shielding winding being divided into two portions and arranged so that said two portions act to screen the two ends of the other secondary winding from the primary winding, there being provided a space between the adjacent ends of said two portions sufficient to leave the central portions of the other windings free.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Filters And Equalizers (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)
US275782A 1938-06-03 1939-05-26 Transformer Expired - Lifetime US2277499A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE214056X 1938-06-03

Publications (1)

Publication Number Publication Date
US2277499A true US2277499A (en) 1942-03-24

Family

ID=5816622

Family Applications (1)

Application Number Title Priority Date Filing Date
US275782A Expired - Lifetime US2277499A (en) 1938-06-03 1939-05-26 Transformer

Country Status (6)

Country Link
US (1) US2277499A (en:Method)
BE (1) BE434669A (en:Method)
CH (1) CH214056A (en:Method)
FR (1) FR855734A (en:Method)
GB (1) GB520622A (en:Method)
NL (1) NL62419C (en:Method)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3052858A (en) * 1958-11-03 1962-09-04 Edcliff Instr Inc Electromagnetic motion responsive device
US3736542A (en) * 1971-06-15 1973-05-29 H Ashe High voltage transformer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3052858A (en) * 1958-11-03 1962-09-04 Edcliff Instr Inc Electromagnetic motion responsive device
US3736542A (en) * 1971-06-15 1973-05-29 H Ashe High voltage transformer

Also Published As

Publication number Publication date
GB520622A (en) 1940-04-29
FR855734A (fr) 1940-05-18
CH214056A (de) 1941-03-31
NL62419C (en:Method)
BE434669A (en:Method)

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