US2678419A

US2678419A - Saturable transformer device

Info

Publication number: US2678419A
Application number: US700234A
Authority: US
Inventors: Bennett Alfred
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1946-09-30
Filing date: 1946-09-30
Publication date: 1954-05-11
Anticipated expiration: 1971-05-11
Also published as: NL84103C; BE503590A; GB647961A; BE476392A; FR953561A; FR62336E; NL161529B; GB706039A

Description

May 11, 1954 A. BENNETT 2,678,419

SATURABLE TRANSFORMER DEVICE Filed Sept. 30, 1946 INVENTOR 1/5. "IL FRED BENNETT A i TORNEY Patented May 11, 1954 SATURABLE TRANSFORMER DEXICE Alfred Bennett, New York, N. Y., 'assignor to Bendix Aviation Corporation, Teterboro, N. J a corporation of Delaware Application September 30, 1946, Serial No. 700,234

2 Claims. 1

The present invention relates generally to electrical current flow control apparatus and more particularly to apparatus of a character adapted for developing, in response to a direct current control signal, a proportional alternating current signal.

Heretofore, in applications where it has been desired to operate an alternating current control system in accordance with a controlling direct current signal, involved networks including thermionic tubes were required. The present invention contemplates the provision of a simple arrangement obviating the past requirement for vacuum tubes, etc, which in response to a direct current control signal, such as that provided by a radio receiver carried by an aircraft and constituting a part of a blind landing system including a localizer and glidebeam path control, for example, will develop a proportional and properly phased alternating current signal for operating given craft surfaces in accordance with the received radio signal or signals.

An object of the present invention, therefore, is to provide a novel electrical inverter which is adapted for developing an alternating current signal proportional to a direct current signal.

Another object is to provide a novel electrical device which is adapted for developing a workable alternating current signal from an extremely weak direct current signal without the necessity for the use of vacuum tubes or other amplifiers.

A further object is to provide a novel and simplified electrical current flow control device which will provide a workable alternating current signal in response to a relatively weak direct 1 current signal whose phase will be determined by the direction of flow of the direct current signal.

Another object of the present inventionis to provide a novel and simple electrical device adapted for use wherever a workable, amplified and properly phased alternating current signal is required in response to a relatively weak direct current signal.

The above and other objects and advantages of the invention will appear more fully hereinafter from aconsideration of the detailed description which follows, taken together with the accompanying drawing wherein one embodiment of the invention is illustrated. It is to be expressly understood, however, that the drawing is for the purpose of illustration and description only, and is not designed as a definition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

Figure 1 is a schematic diagram showing the various electrical circuits of the novel apparatus constituting the subject matter of the present invention;

Figure 2 is a detail view, showing the aiding relation at a given time of the fluxes in the center leg of one of the cores of Figure 1; and,

Figure 3 is a detail view, similar to that of Figure 2, showing the opposing relation during the time under consideration of the fluxes in the center leg of the other of the cores of Figure 1.

Referring now to the drawing for a more detailed description of the novel electrical apparatus constituting the subject matter of the present invention, the latter is shown in Figure 1 as comprising a pair of similar cores I0 and H formed of magnetically permeable material such as Permalloy or Mumetal, for example, core H! being provided with a center leg [2 and spaced outer legs [3 and I4 and core ll being similarly provided with a center leg [5 and spaced outer legs I6 and I1.

Primary windings l8, iii, 20 and 2| are provided for cores [0 and H, windings I8 and I9 being arranged on outer legs l3 and i4, respectively, of core Ii) and windings 20 and 2| being arranged on outer legs IS and I1, respectively, of core Ii. One end of winding 58 is connected by way of a conductor 22 with one side of. a suitable source of alternating current (not shown) while the opposite end of winding it connects by way of a conductor 23 with one end of primary winding 19. The opposite end of the latter winding, in turn, connects with. one end of primary winding 20"by way of a conductor 24 while the opposite end of winding 28 connects by way of a conductor '25 with one end of winding 2!, the opposite end of the latter being connected by way of a conductor 25 with the opposite end of the alternating current source.

It will be apparent that primary windings I8, I9, 29 and 2! are all connected in series aiding relation with each other and with the source of alternating current supplying the primary windings so that windings l8 and I9 aid each other in circulating flux, indicated by the arrows 2? in Figure 1., around the long circuit of core 1-0 but oppose each other in the center leg [2 while windings 2i) and 2| will aid each other in circulating flux, indicated by the arrows 28, around the long circuit of core H but oppose each other in the center leg l5.

Secondary windings

29, 30, 3| and 32 are further provided on both cores It and II and are so arranged that they are normally unaffected by the fluxes traversing the long circuits of both cores, i. e., no signal will appear at the secondary output. To this end, secondary windings 29 and 30 arranged on legs l3 and (4, respectively, of core it are connected in series by way of a conductor 33 while windings 3i and 32 arranged on legs l8 and H, respectively, of core H are connected in series by way of a conductor 34, the free end of winding 29 being connected by way of a conductor 35 with one side of a device 36 responsive to an alternating current signal and the free end of winding 3! being connected with the-opposite side of the signal responsive device by way of a conductor 3'1. While the secondary windings of each pair are connected with one another in series aiding relation, the pair 29 and 3G is connected in series opposing relation with the pair 3! and 32, this being accomplished through a conductor 38 connected to the free end of winding 30 of the first pair of windings and the free end of winding 32 of the second pair of windings. Thus, for any signal appearing at secondary windings ill and 30 due to current flow in primary windings l8 and IS an equal and opposits signal will appear at secondary windings 3| and 32 due to current flow in primary windings 2d and 25 with the net result that no signal will be provided by output conductors 35 and 3'! to device 36.

Direct current control windings in the form of coils 39 and 4B are, furthermore, provided on center legs l2 and i5, respectivel of cores l8 and H and are interconnected with each other in series relation by way of a conductor 41 and with a direct current signal generator 42 by way of conductors ll and 44. With the arrangement thus far described, notwithstanding the amplitude or the direction of the D. C. signal developed by generator 42, both cores will have fluxes threading the center legs thereof due to current flow in the control coils which are of equal intensity so that the balance of the electrical system is unchanged and no signal will appear at output leads 35 and 31.

In order that workable and properly phased alternating current signal may be available at

secondary outputs

35 and 31 to energize device 36 in response to a relatively weak direct current control signal applied to

coils

39 and 40, a second pair of direct current biasing control windings in the form of

coils

45 and 46 are pro vided on center legs l2 and 45, respectively, of cores ill and H, which are interconnected by way of a conductor 4? in series opposing relation, the free end of coil 65 being connected to one side of a suitable source of D. C. current, such as a battery 48, for example, by way of a conductor 49 the free end of coil 46 being connected to the opposite side of the battery by way of a conductor fill. Although

coils

45 and 46 have been described as being connected in series opposed relation, it is to be understood that they could be connected in series aiding relation as well, in which event control coils 39 and would. be connected in series opposed relation. Whichever arrangement is selected the ultimate result will be the same.

Assuming D. C. coils and 45 to have been connected in series opposed relation in which event control coils 39 and 4B are in series aiding relation and with no D. C. signal applied to the latter coils. magnetic flux will flow in center leg I2 of core It due to D. C. current in coil 45 in the direction indicated by arrow 5| in Figure 2 while magnetic flux the center leg l5 of core H due to D. C. current in coil 46 will flow in the opposite direction as indicated by arrow 52 in Figure 3. While these fluxes are in opposing relation in the two center legs of the cores, both cores are saturated with a similar amount so that the system is undisturbed and no signal will appear at device 36. It will now be readily apparent that the direction of the fluxes designated by arrows 5| and 52 will be determined by the manner that

coils

45 and 46 are connected to D. C. source 48.

Assuming, further, that a direct current signal is developed by generator 42 to flow within control coils 38 and 4 additional fluxes will be developed in both center legs to, in one case, aid the flux developed by the other D. C. coil in one of the center legs of one of the cores and to oppose the flux developed by the other D. C. coil in the other center leg of the other of the cores. For example, as shown in Figure 2, the flux resulting from current flow in control coil 39 will be in the direction indicated by the arrow 53 to aid the flux 5! due to current flow in coil 45 and thus saturate core It to make core I!) and its windings l3, l9 and 29, 30 a poor transformer while the flux resulting from current flow in control coil 49 will be in the direction indicated by the arrow 54 to oppose the flux 52 due to current flow in coil 4G to neutralize the effect of the latter fluxes produced by current flow in coils 4i! and it to thereby make core H and its

associated windings

2t, 21 and 31, 3?. a good transformer. As a result, the electrical system is unbalanced and an alternating current flows in secondary windings 29, 30, Si and 32 to energize device 36.

The relation of the magnetic fluxes illustrated in Figures 2 and 3 of the drawing is that due to direct current flow in one direction within

control windings

39 and 40 as a result of which an A. C. signal is available at

secondary outputs

35 and 37. It will now be apparent that for a reversal in the direction of current flow in

control coils

39 and 40 developed by generator 42, the ilux 53 of Figure 2 will be reversed to oppose the flux in center leg [2 due to current flow in coil 45 and thereby make core in and its. associated primary and secondary windings a good transformer while the flux 54 of Figure 3 will be reversed to aid the flux in center leg 15 due to current flow in coil 46 and thereby make core II and its associated primary and secondary windings a poor transformer. The electrical system is, thus, again unbalanced and an alternating current flows in the secondary windings which is substantially out of phase with the current flow induced in the same windings by the direction of current flow in

control coils

39 and 40 first considered above.

It will now be apparent to those skilled in the art that a novel electrical device has been provided which is adapted for developing a workable, amplified and properly phased alternating current signal from an extremely weak direct current signal without the necessity for the use of vacuum tubes or other amplifiers.

Although but one embodiment of the invention has been illustrated and described, various changes and modifications in the form and relative arrangement of parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention. Reference is therefore to be had to the appended claims for a definition of the limits of the invention.

I claim:

1. An inverter of the kind described comprising a pair of core members of magnetically permeable material, a primary Winding on each of said core members adapted to be energized by an alternating current source, a secondary winding on each of said core members connected independently of said alternating current source, a biasing winding on each of said core members adapted to be energized by a direct current source independently of said alternating current source and independent- 1y of said secondary windings to produce a unidirectional magnetic flux in each of said cores, a signal source for producing direct current signals independently of the alternating current source and independently of the secondary windings, a control winding on each of said cores connected to said signal source and arranged to increase the unidirectional magnetic flux in one of said core members and to decrease the unidirectional magnetic flux in the other core member in response to the direct current signals so that alternating currents corresponding in phase to the polarity of the direct current signals are induced in said secondary windings, and means con ected to said secondary windings and controlled by said signal source and responsive solely to the alternating currents induced in said secondary windings.

2. An inverter of the kind described comprising a pair of core members of magnetically permeable material each having a central leg and a pair of spaced outer legs, primary windings on the outer legs of said core members adapted to be energized by an alternating current source, secondary windings on the outer legs of said core member connected independently of said alternating current source so that no signal is induced in said secondary windings solely in re sponse to energization of said primary windings, biasing windings adapted to be connected to a direct current source independently of the alternating current source and independently of said secondary windings for producing a unidirectional magnetic flux in each of said core mem bers, a signal source adapted to produce direct current signals independently of the alternating current source and independently of said secondary windings, control windings on the central legs of said core members connected to said direct current signal source to decrease the unidirectional magnetic fiux in one of said core members and to increase the unidirectional magnetic flux in the other core member in response to direct current signals so that alternating cur rents are induced in said secondary windings corresponding in phase to the polarity of the direct current signals, and mean connected to said secondary windings and controlled by said signal source and responsive solely to the alternating currents induced in said secondary windings.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,661,740 Steekle Mar. 6, 1928 1,824,577 Sorensen Sept. 22, 1931 1,914,220 Sorensen et al June 13, 1933 1,997,657 Schmutz Apr. 16, 1935 2,053,154 La Pierre Sept. 1, 1936 2,164,333 Burton July 4, 1939 2,229,952 Whitely et a1. Jan. 28, 1941 2,2'%7,983 Barth M July 1, 1941 2,388,070 Middel Oct. 30, 1945 2,529,450 Hornfecl: Nov. 7, 1950 2,574,438 Rossie et al. Nov. 6, 1951