Power switch with transfluxor type magnetic cor

Vanderiet, E. K.

English

NASA Technical Reports Server

REPLY TO 
ATTN OF: G p  
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
WASHINGTON. D.C. 20546 
~ ~ I / S c i e n t i f i c  & Technical Information Divioion 
Aftsnttonw Mi88 Winni6 M. Mcrxgan 
F ROM t ~ ~ / ~ f f i c e  of Assiqtaqt General Counsel for  
Patent Matters 
SUBJECT: Announcement of NASA-Owned U. S. Patents i n  STAR 
In accordance with the procedures agreed upon by Code GP 
and Code U S I ,  the attached NASA-owned .U. S; Patent is being 
forwarded for  abstracting and announcement i n  NASA STAR. 
The following i n f  omatLon i e  providedi 
I 
U. S. Patent No. 
Government or 
Corporate Employee 
Stanford Reserch Ins t i tu te  
. Menlo Park, California 
Supplementary Corporate 
Source (if  applicable) t J P L  . 
. , 
NASA Patent Case No. 
NOTE - I f  t h i s  patent covers an invention made by a corporate 
employee of a NASA Contractor, the following is applicable: 
yes Q NO 
. Pursuant t o  Section 305(a) of the National Aeronautics and 
Space Act, the name of the Administrator of NASA appears on 
the f i r s t  page of the patent; however, the name of the actual 
inventor (author) appears at the heading of Column No, 1 of 
the Specification, following the words ,' , with respect t o  
I N 
~nclosure o .O (ACCESSION UMBER) 
Copy of  Patent czited above1 5 .- 4 0 
LL 
, & 5 9 (NASA CR OR TMX OR AD NUMBER) (CATE 
IL 
https://ntrs.nasa.gov/search.jsp?R=19710015327 2020-03-17T02:57:54+00:00Z
Nov. I?', 1970 +. O. PAINE, DEPUTY 3,541,346 
ADMINISTRATOR OF THE NATIONAL AERONAUTICS 
A N D  SPACE ADMlNlSTRATlON 
MAGNETIC POWER SWITCH 
Filed July 31, 1968 
0 F 
INPUT SO 
P O W E R  
FIG. I 
FIG. 2 a  FIG. 2 c  
A T T O R N E Y S  
3,541,346 United States Patent Ofice ..." , ,,,, 
P 
I 2 
which is characterized by substantizlly all tb; aforemen- 3,541,346 
MAGNETIC POWER SWITCH tioned desirable properties. 
T.  0. Paine, Deputy Administrator o f  the National Aero- A further object of the invention is to prawde a aclr- 
nautics and space Administration, with respect to an tively simple switching arrangement \.\iblcI? employs a 
invention of ~ d ~ i ~  JM. van D~ ~ i ~ t ,  Mountain V iew ,  magnetic core operable so that the switching o l  the '11- 
Calif. rangement from OFF lo ON docs not ~esu l i  n  ciloneor s 
Filed July 31, 1968, Ser. No .  749,181 power transfer to a load. 
Pnt. GI. GEPc 11/08 Still a further object of the invention 1s the pi ovisron 
U.S. Cl.  307-88 5 claims of magnetic core-utilizing switching arlnilgemcilt rn 
which excessive core drive, produced during power elan\- 
fer between a souice and a load, does nol cl~ange t\e 
CT OF THE DISCLOSURE state of the switching arrangement These and other objects of the invention ale achieved 
A magnetic power switch is disclosed which com- by providing a switching arrangement or samply a sw~tc"i 
prises a transfluxor-type magnetic core. with a major 1.j in which a transflwor-type magnet-c coie. wrib a mino1 
and a minor aperture. The state of the switch is con- and a major aperture, is employed The fir~x path abol t 
trolled by controlling the direction of flux about the ma- the minor aperture may be thought of a.; bc171g of I unrt 
jor aperture. Separate decoupled power sources and pow- cross-sectional area. It defines a first leg. hereaftel rc- 
er loads are coupled to two core legs, one of which is ferred to as leg A, between the majo: and ,nrnai ;.pel- 
between the major and minor aperture and the other 20 tures' periphery, and a second, leg B, betwee? the 11311 o* 
between the minor aperture and the core periphery. The aperture and core periphery. The flux path abort thz 
switch is turned ON by setting the flux in one of these major aperture defines a control leg of two unats of 
legs. The leg is cleared when power is transferred from cross-sectional area. 
the source to the load coupled thereto, at the same time The state of the switch is controlled by cor7:r olling thc 
setting the flux in the other leg, which is cleared when 25 direction of flux about the major apertuie ~cp~csenled by
power is transferred from the source, to the load coupled the control leg. In the OFF state thc two ~ r i t s  of Acbx 
thereto. in the control leg are in the same d~rcctioii such z s  
clockwise, with one unit forming an orttei loop a b o ~ t  
ORIGIN OF INVENTION both apertures and an inner loop aborit the ~ a l o ~  aper-
The invention described herein was made in the per- 
formance of work under NASA contract and is subject 
to the provisions of Section 305 of the National Aero- 
nautics and Space Act of 1958, Public Law 85-568 (72 
Stat. 435; 42 USC 2457). 
BACKGROUND O F  THE INVENTION 
Field of the invention 
This invention generally relates to a magnetic switch- 
ing arrangement and, more particularly, to a power 
switch 'which uses a transfluxor-type magnetic core. 
ture only. These directions of flux In legs A and B may 
be thought of as the clear flux direct~on Tile s7,ii:cEz 7s 
switched ON by reversing the direction o: flux of the 
inner loop so that the flux in leg A 1s set. 
Separate decoupled sources and decorlpied loads are 
inductively coupled to legs A and B so that  airel ihe 
switch is turned ON, power may be supp'led Eloin the 
source to the load, coupled to Ieg A, by d ~ r v ~ n g  the flvx 
therein to the clear direction. With the loads and sources 
decoupled, flux switching occurs 111 the .;hortest aatn 
which is around the minor rather than the rmjoi aper- 
ture. Consequently, when leg A is driven to tbe cEcar d - 
rection, leg B is set. A subsequently suppl~ed slgnai froi? 
a source, associated with leg B, cauies the firrx ther-111 LO 
be driven to the clear direction and thcicbv ~ndircc a 
Description of the prior art 45 signal which is supplied to the load which iE associated 
with leg B. 
The prior art is replete with systems and devices which Since in operation legs A and B are driven only in the 
employ magnetic cores for data storage, logic perform- clear direction by their respective sources, any setting 
ance and signal switching. Typically, the cores, which of flux around the major aperture due to dirves on the 
are employed, have magnetic properties which are char- 50 minor aperture, is avoided. Thus, the rnzximum allow- 
acterized by a substantially rectang~~lar hysteresis loop able drive on the minor aperture by either of the souaces 
so that the core may be switched between two stable is not critical. Furthermore, the operation of the switch 
states of magnetic remanence. When magnetic cores are of the present invention is such that any overselt~ng of 
employed to function as a switching arran,oement. means the major aperture is automatically cleared out by the 
are provided to switch the arrangement b e t ~ e e n  ON and 5.5 subsequent drive on the minor aperture. Consequently, 
OFF states. Additional means are provided so that only the drive necessary lo ttorn the ON s in the ON state may signals be switched between one not critical. 
or more signal sources to one or more loads. When the switch is in the OFF state, it plesenis a very 
The desired properties of such a switching arrange- low impedance to the power source; large currents nsriit ment are high power handling capability, fail-safe opera- 60 be prevented from flowing by one of the follawing nleans: 
tion, simplicity and reliability in switching from the ON (1) using a current source for [he power source, (2) to the OFF state and minimization of the likelihood of a connecting the power source to a ,nroup of these 
change of state, especially from OFF to ON, due to the connected in series and insuring that any one but only 
supply of excessive power from any of the SOLIrces to a 
one switch in the group will be on at ail times, and load. 6.j (3) providing another minor aperture on the core which 
OBJECTS AND SUMMARY OF THE INVENTION is connected in series with the given minor apeirrrre to 
switch, when necessary, to provide an impedance for the 
It  is a primary object of the present invention to pro- power source. 
vide an improved magnetic core-utilizing switching ar- The novel features of the invention are set forth with 
rangement. 70  particularity in the appended claims. The illvention will 
Another object of the present invention is the provi- best be understood from the following description when 
sion of a magnetic core-utilizing switching arrangement read in conjunction with the accompanying drawings 
3,541,346 
3 
BRTEL 9ESCB'IP'FION OF THE DRAWINGS 
4 
Attention is now directed to FIGS. 2(a) through 2(d) 
g-gG. is a schematic and block diagram which are schematic diagrams of the magnetic core 10, 
of the present ~nvention; shown in FIG. 1, illustrating different flux states thereof. 
FliGS. 2(0 j  through 2(d) are schematic diagrams of and 42 represent flux the 
the inagnctic core illustrating various flux states thereof 5 major and, particularly in leg C, 
"vvh~cl~ are ~ l ~ e f u l  in explaining the novel features of the while arrows 43 and 44 represent flux directions in legs 
invertion; and A and B, respectively. FIGS. 2(a) and 2(b) illustrate 
FAGS, 3(n) throagR 3(c) are additional schematic the flux states when the switch is in the OFF and ON 
dlagrarils of the magnetic core illustrating various flux States, respectively. FIG. 2(c) illustrates the flux condi- 
stateG, ther eo:. tions in the core after leg A is driven to its clear state, 
and the flux conditions after leg B is driven to clear are 
DESCRIPTION OF THE PREFERRED illustrated in FIG. 2(d). 
EMBODPhlENTS As seen trom FIG. 2 ( n ) ,  when the core is in the OFF 
~~f~~~~~~ is now nlade to FIG. 1 wherein numeral 10 state, the two units of flux about the major aperture are 
desagnates a eransAuror-type magnetic core with a major 15 in the Same direction. One flux unit, represented by arrow 
zpertilre 12 and a minor aperture 13. The core is con- 41, forms a clockwise directed flux loop with the flux 
i t~~ic ted  to d e h e  a control leg 14, hereafter referrcd to in leg about both apertures, while the other flux unit, 
ls rcg C, bztweeil thz nlajor aperture and the core pr iph-  represented by arrow 42, also forms a clockwise directed 
cry The cure portion between apertures 12 and 13 flux loop with the flux in leg A about major aperture 12. 
defines a leg A and the portion between aperture 13 and 20 For explanatory purposes the flux in both legs A and B 
:he core periphery defines a leg B. The cross-sectional "aY be thought of as pointing down when the switch is 
.brea of each o i  legs A and B may be thought of as repre- in the OFFstate. 
\en"ing one ( I )  unit, while the cross-sectional area of The switch is turned ON by a pulse on one of the 
leg iG IS of two units. control windings, such as winding 16 (FIG. I) ,  which in 
eoiltloi leg e: slown inductively coupled to a source 25 essence reverses the direction of flux about aperture 12. 
of state cor~trol piilses 15 by windings 16 and 17. To This is illustrated in FIG. 2(b) by the counterclockwise 
s,mpllfy 1-LG. 1, all windings are shown as single turn. flux loop about the aperture 12. Thus, in the ON state the 
,An input wtnding 28 connected between a reference PO- two units of flux in leg C are in opposite directions. Also, 
,ential, s~ich as ground and the emitter of a diode 22 is when the switch is first turned ON, the direction of flux 
' ;~oand about leg A, while a similar input winding 23 30 in leg A (arrow 43) is up. 
connected between giound and the emitter of a diode Voltage f ~ o m  souice 30 ind~~ces  current in winding 21 
24 is wound <tbout leg B. The collectors of diodes 22 driving leg A to its clear state, as shown in FIG 2(c) by 
and 24 ale connecied to opposite ends of a secondary arrow 43 pointing down. Due to the decou~led load and 
windrag 26 of a power transformer 27, whose primary Source impedances, flux switching occurs around the 
wiadrng 28 is connected to a source of input power 30. 35 minor aperture 33. Consequently, the flux in 1% I 3  (arrow 
Legs A and B are further wound by respective output 44) points UP. The flux in leg C, however, does not 
wiridings 31 and 32, each having one end connected to change, remaining in opposite directions. A subsequent 
ra ?ohd 34 through respective diodes 35 and 36. The other voltage from source 30 induces a current in winding 23 
end of each of the two-latter-mentioned windings is which reverses the flux in leg B, driving it to its clear 
grouniied It si~ould be pointed out that in FIG. 1 wind- state. Due to the reversal of flux about aperture 13, the 
Ings 16 dnd 17 are wound about leg C in opposite senses, flux in leg A is driven to its set state. This is again repre- 
and that similarly windings 21 and 23 about legs A and sented by arrow 43 pointing up in FIG. 2(d). 
1% aye of opposite senses. Contrary thereto, windings 31 From the figures it should be appreciated that once the 
and 32 aie x~ound in the same sense. switch is turned ON, successive voltages are applied to  
B~iefly, the mag~etic switch of the present invention 45 the load 34 by alternately driving legs A and B to their 
is operable to be in either an OFF, sometimes also re- clear states. When leg A is driven to such a state, the flux 
ferrcd to as the clear state, or an ON or set state. The around the minor aperture is in one direction, such as 
staB is controlled by controlling the direction of mag- countercloclrwise. in which case the flux in leg B is set. 
netlc flux about the major aperture 112. Power is trans- Then, when leg B is cleared, the flux around the minor 
Cesanle ro Load 34 lrom source 30 only when the switch 50 aperture is in a clockwise direction and leg A is set. The 
is rt? the ON state or simply ON. When the switch or switch may be turned OFF by applying a control pulse 
core 10 is ON, the direction of flux in leg A is opposite to clear winding 17 which switches the direction of flux 
the OFF or clear flux direction therein. Current in wind- represented by arrow 42 so that the two units of flux 
any: 21, reveises the flux direction in leg A to its clear arrows 411 and 42 in leg C are in the same direction. 
state. The flux reversal induces a voltage in winding 31 55 The novel switch has an additional important ad- 
w h i ~ h  is supplied to load 34. Also, the flux reversal in vantage which consists of automatic clearing of excess 
;a:: 4 in essence reverses the flux direction in leg B. Thus, flux, which may be set therein, when the switch is turned 
when aoltage is applied by source 30 the current, in- ON. This advantage may best be explained together with 
duced in w~ndlng 23, returns the direction of flux in leg FIGS. 3(a) ,  3(0) and 3(c), which are schematic diagrams 
B to its clear state, inducing a voltage in output winding GO of the core 10 illustrating flux states. 
32 wnich is in t u n  supplied to load 34. Basically, FIG. 3(a) illustrates the case in which more 
The impedances of the load 34 and source 30 are de- than one unit of flux is switched in the countercIockwise 
coupled from the flux switching in leg B when leg A is direction in leg C when the switch is first turned ON. 
driven, by diodes 36 and 24, respectively, while diodes The proper flux switching is represented by downward 
35 and 22 lsolaie the source and load from leg A when 65 arrow 42, as is the case in FIG. 2(b), while the excess 
leg B is drlven. Consequently, flux switching occurs in switched flux is represented by short arrow 51. This ex- 
the shortest path, which is around the minor aperture cess flux forms a closed flux loop around both apertures 
13, rather than around the major aperture 12. It should so that part of the flux in leg B is in the set state, as 
also be pointed out that the power transfer is achieved represented by upward arrow 52. Consequently, the 
by alternately dliving legs A and B to their clear or OFF 70 amount of set flux in leg A is less than the amount of 
state. Such a driving arrangement together with the load flux in the clear state in leg B. 
and sonire decoupling greatly enhance the operation of When leg A is driven to the clear state, it has more flux 
the switch of she present invention since they prevent the to switch to the clear state, i.e., down, then leg E has 
sv,i%ch froin being switched to its OFF state due to ex- to switch up, since some of the flux in leg B is already 
ces:rve drrve currerts. 76 up (arrow 52). Consequently, the flux in leg B is switched 



Magnetic power switch Patent

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server