US2694797A

US2694797A - Angle transmitter for gun control devices

Info

Publication number: US2694797A
Application number: US215821A
Authority: US
Inventors: Lindblad Lars Alfred
Original assignee: Bofors AB
Current assignee: Saab Bofors AB
Priority date: 1950-03-21
Filing date: 1951-03-15
Publication date: 1954-11-16
Anticipated expiration: 1971-11-16

Description

Nov. 16, 1954 L. A. LINDBLAD 2,694,797

ANGLE TRANSMITTER FOR GUN CONTROL DEVICES Filed March 15, 1951 F l G i 2 INVENTOR.

LARS' ALFRED LINDBLAD ATT RNEY United States Patent-t) NG RAN MITTER OR. CONT L DEYIGES".

LarsAlfred Lindbiad, Grondal, Sweden, assignor to .Akfiebolaget Bofors, Bofors Sweden, a corporation of Sweden Appl c t on MarchlS, 195.1,,Serial No. 215,821- a msp i itn annticatia wed n-Ma h. :2 .1 0 Clai s! .3;i :-1.1;.'.

This nt o la es qscttih fo o py tems n which a variation o f one magnitude is refiected by a correspohdingtchange in an t er ma itud Mo partiwlarly, h v ht qh re ates to..-t ah' m tt Q j h yp includinga stator, and a rotor and in which the, voltage output of the rotor is a fnnction of the rotational angle of the rotor so that the voltage at therotor terminals is indicative f he an ular. ph li hq th -r to Hen e, if the n t e tx e' ransmit ed. is hsed o on ro the s a p ti n. he. o r, the esultin o ta appearing hc h q e hals canbe. emp y p es a w d m itud s phhd hs posi on.

An e n mit e s ene al typ abov e e red to, are useful r rio s pu poses.- ew. Pr e red and particularly advantageous field of application of angle transmitters is as components of control mechanisms r e t a an lat a mi g. of sun. G n trol mechanisrns of the type to which reference is made herein aremore fully described. for instaneein the-co- Pt d s Pa appl c tion. S r- No. 07,95 file h hh: ary 26, 1951, now abandoned;

h angle a smit ers of he. afQ S l QIYW an n: duced alternating voltage or an envelope of the induced t e. is obtained the rotor. erm na s. w en .thi ista field is excited and the rotor isrotated, This ,output voltage is usually notof'a pure .sinefOrrnbut includes m nics r. hep mse or whic nslea ah initters of the aforesaid 'type 'are. often employed, pa rticularlv n se a comp nents a. sun o t m c n the pr s ce ot'httttn hics. s. ndesirab and it is preferable that outputvoltag .Otthe envelopethereof be as nearly sine-shaped or s nusoidal aspossible,

c g y, the p ih ipalihbie t h .pr. .s ht. .v. nr tion is. to provide novel and improved meansby which the harmonic components of the rotor outputvoltage are substantially eliminated in asimple and eftieient manner, Another morespeeifieobiect 'of the invention is, to Provide novel nd mpr ved. p s al m ahstas d st n: c h o rc t an apab t ub t nt ally eliminating e f thsaidhhdss t hlc a monics,

A still more specific obieet of the inventionistopro: i e Ph c m an hav awmnon ht which. a be independently j te o a tet a ele ed.harm cs of the output voltage of therotor.

t and u the bie. a ea u s. hda xant acs 0f the invention will be pointed I p hereinafter, and. set fhtth n the pp de la ms. orm n P o e pp ication.

According Q- w pr fierred exem li s i hot the invention these aforesaid physieai means compriSfi. one or more adihstahly u t d ma he zah emembe 's, thctposition of which relative to thern ss of'thestatortand the rotor can be ar ed a t 150? mortrgroqves h hc h t q of he at r ht acin t c ota itha o t h d Configuration f he a sisr cves s a etermin d by mathematical calculations or analysis of the A.-C out: put voltage of the rotor well. understood in the art for the purpose here in question.

In the accompanying drawing a now preferred ernbodiment of the invention is shown by way of illustration and not by way of limitation.

In the drawing:

Fig. 1 isafragmentary perspective view, partly in sectiotn, of'an angle transmitter aecording'tothe invention, an

Fig. 2 is a plan view ofj i g 1, therotor ;being omitted.

2,694,797 Patented Nov. 16, 1954 Referring now to-the figures-in detail, the transmitter accordingto the invention is exemplifiedas atransformer having a. stator shown as comprisingastator body'l of substantially rectangular outer shape and-formed-with an opening thereinwithinwhich the field windingsand the rotor. are. mounted. Thestaton body is illustrated as being of; the laminatedtype.composed of afnumber. of magnetizable plates separated by insulation spacer plates.

The stator is,provide d with two field windings 2 and 3which are disposed as canbestbe seen on Fig. 1 and terminate

inpIimary input terminals

4 and 5. The stator windings are so connected that. thestator fields aideach other. when the.field. windi 'lgs are excited with a D.-C. and A.-C. voltage respectively or an A.-C;. voltage only. In the exemplification an A.-C. voltage is suppliedl The rotor is shownas acylindrical. body 6 madeof insulation material.and havingan axial slot 7 therethroughl. This slot. serves to house a rotor winding 8, the terminals of which are connected through. an axial bore13 in cylinder 6.to sliprings 9 and-10 respectively. These slip-rings areslidablyengaged bynbrushes. 11 and 12 resp ectiv1y which in turn are connected to secondary output terminals 16. and. 17. In other words, the output voltage of. therotor is .availableat terminals 16 and'17. assuming th fieldwiudings of thestator be excited :and rotor .6 berotated relative .to the statorv field.

Eor. thepurpose of reducing or. eliminating the harmonies of the output voltage of the rotoroneor more magnetic members arev provided whichare mounted-adjustably relative to .the mass. of. the stator and to the rotor. winding, These adjustable magnetic members can taltevarious shapes and the adjnstability of: the members canbe. accomplished by various means suitable for this purpose, It' has been found that. the desired purpose can be, attainedina convenient and eflicientmannerby providing two pairs. of screws 19,; 20 and 21, 22 made of magnetiz able or magnetic material such. as iron ,or an iron alloy.

As will be noted. screws 20 and 22, are threaded in the upper wall portion of the stator body 1 andscrews 19-,and,21 .in the lower portionof the stator. body. Fur.- thermore, screws, 19. and 21).. are. disposed. in .alignment across the, rotorasarealso screws 21. and 2 2.

As is well, known, the output voltage or the envelope of the output voltage which appears at terminals 16. and 1?] canrbe expressedbythe, following equation:

wherein B isthe turningangle or therotational angle of he hto It has been foundthat adjustment of the screws permits to eliminate or at least to reducethe components of the rotor output voltage and of the envelope of the voltage which are' multiples other than the multiple one of the turning angle of the rotor, mother Words, the compo nents which are harmonics. More specifically, it has been found th tasimultaneous screwing. in of the

screws

20 and 2 2 or of'the screws 19' and 21 results in a reduction of the component b; sin 3;}. Simultaneous screwing in of. the screwsztl and 2 1 causes an increase of the

component a3 cos

3,8 and simultaneous screwingv in of the screws 19 and .22 results in a decrease of the. same component,

For further reducing the harmonic components of the output voltage of the rotor, a groove 18 in the lower inner wall portion of the stator body and-a groove 23 in the upper inner wall portion of the. stator body are provided As will be noted, th e two grooves have. the same configuration and are in transverse alignment across the rotor as is clearly shown on Fig. 1. The specific shape of thegrooves, which are shown here as shallow andwide grooves, can bedetermined by'mathematical calculations'known for such purpose .or more conveniently by a frequency analyzer also, known for the purpose. Such analyzer permits to analyze the envelope of the outputyolta'ge', and the analysisthlls Obtained serves to determine the configuration of'the grooves and the disposition thereof; Inasmuch as the specific configuraso tion' of the grooves is not claimed herein, itjis believed that a detailed description I of the. kngwn methods or means by which the specific configuration of the grooves can be ascertained is not essential for the understanding of the invention. The grooves do not necessarily have the illustrated configuration. Furthermore, several pairs of grooves may be found to be advisable. It has been found that the grooves serve to eliminate nearly completely the component b3 sin 318 of the voltage or the envelope thereof.

While the invention has been described in detail with respect to a certain now preferred example and embodiment of the invention it will be understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

I claim:

1. Means for suppressing harmonics in an A.-C. angle transmitter in form of a transformer having a stator including a magnetic core with pole faces and a field winding thereon adapted to be connected with a source of voltage, and a rotor including a non-magnetic core and a winding thereon, the said rotor being disposed concentrically with the pole faces of the stator core, the A.-C. voltage output of said rotor winding in response to a rotation of the rotor being a function of the angular position of the rotor and containing harmonics, the said suppressing means comprising at least one member of magnetizable material mounted in the stator core adjustable in position relative to the mass thereof and disposed transversely to the axis of the rotor, adjustment of the position of the said member affecting the harmonics of the voltage output of the rotor for the purpose aforesaid.

2. Means for suppressing harmonics in an A.-C. angle transmitter in form of a transformer having a stator in.- cluding a magnetic core with pole faces and a field winding thereon adapted to be connected with a source of voltage, and a rotor including a non-magnetic core and a winding thereof, the said rotor being disposed concentrically with the pole faces of the stator core, the voltage output of said rotor winding in response to a rotation of the rotor being a function of the angular position of the rotor and containing harmonics, the said suppressing means comprising at least one recess in a portion of the stator core facing said rotor winding, the said recess effecting a reduction of the harmonics of the voltage output of the rotor.

3. Means for suppressing harmonics in an A.-C. angle transmitter in form of a transformer having a stator including a magnetic core with pole faces and a field winding thereon adapted to be connected with a source of voltage, and a rotor including a non-magnetic core and a winding thereon, the said rotor being disposed concentrically with the pole faces of the stator core, the A.-C. voltage output of said rotor winding in response to a rotation of the rotor being a function of the angular position of the rotor and containing harmonics, the said suppressing means comprising at least one member of magnetizable material mounted on the stator adjustable relative to the mass of the stator core and disposed transversely to the axis of the rotor core, adjustment of the position of the said member affecting the harmonics of the voltage output of the rotor for the purpose aforesaid, and further comprising at least one recess in a portion of the stator core facing said rotor winding, the configuration and position of the said recess reducing the harmonics of the voltage output of the rotor for the purpose aforesaid.

4. Means for suppressing harmonics in an A.-C. angle transmitter in form of a transformer and having a stator including a magnetic core of generally rectangular crosssection and formed with pole faces, the said core having an opening therein, a field winding mounted within said opening of the stator core, and a rotor including a nonmagnetic core and a winding thereon and rotatably mounted within the stator opening, the said rotor being disposed concentrically with the pole faces of the stator core, and A.-C. voltage output of said rotor winding in response to a rotation of the rotor being a function of the angular position of the rotor and containing harmonics, the said suppressing means comprising at least one member of magnetizable material, the said stator core being formed with a second opening disposed transversely to the rotor axis, and the said magnetizable member being fitted in said second opening adjustable relative to the mass of the stator and disposed transversely to the axis of the rotor, adjustment of said member relative to the stator core and the axis of the rotor affecting the harmonics of the voltage output of the rotor for the purpose aforesaid.

5. Means for suppressing harmonics in an A.-C. angle transmitter in form of a transformer having a stator including a magnetic core of substantially rectangular cross-section and formed with pole faces, the said core having an opening therein, a field winding mounted within said opening of the stator core, and a rotor including a non-magnetic core and a Winding thereon, the said rotor being rotatably mounted within the opening of the stator core, the said rotor being disposed concentrically with the pole faces of the stator, the A.-C. voltage output of said rotor winding in response to a rotation of the rotor being a function of the angular position of the rotor and containing harmonics, the said suppressing means comprising a pair of magnetizable members, the said stator core being formed with two additional openings extending transversely through the mass of the core, each of the said magnetizable members being fitted in a respective one of said transverse stator openings adjustable relative to the mass of the stator core and the axis of the rotor, adjustment of the positions of said members relative to each other and to the mass of the stator core and the rotor core affecting the harmonics of the voltage output of the rotor for the purpose aforesaid.

6. Suppressing means according to claim 5, wherein the said two magnetizable members are mounted in wall portions of the stator core situated diametrically opposite to the rotor axis.

7. Suppressing means according to claim 5, wherein two pairs of said magnetizable members are provided, the two members of each pair being disposed in opposite wall portions of the stator core in diametrical alignment one with the other, displacement of said members of each pair varying the distance of the respective members relative to each other and to the mass of the stator and the rotor.

8. Suppressing means according to claim 4, wherein said magnetizable member comprises a screw member threaded in said second opening of the stator core. I 9. Means for suppressing harmonics in an A.-C. angle transmitter in form of a transformer having a stator including a magnetic core with pole faces and of substantially rectangular cross-section and formed with an opening therein, a stator field winding mounted within said opening of the stator core, and a rotor including an nonmagnetic core and a winding thereon and rotatably mounted within the stator, the said rotor being disposed concentrically with the pole faces of the stator core, the A.-C. voltage output of said rotor winding in response to a rotation of the rotor being a function of the angular position of the rotor and containing harmonics, the said suppressing means comprising at least one pair of shallow grooves disposed in diametrically opposite inner wall portions of the stator core defining said opening and facing the rotor, the configuration and position of the said grooves reducing the harmonics of the voltage output of the rotor for the purpose aforesaid.

10. Means for suppressing harmonics in an A.-C. angle transmitter in form of a transformer having a stator including a magnetic core with pole faces and of substantially rectangular cross-section and formed with an opening therein, a field winding mounted within said opening of the stator core, and a rotor including a non-magnetic core and a winding thereon, the said rotor being rotatably mounted within the opening of the stator core and disposed concentrically with the pole faces of the stator, the A.-C. voltage output of said rotor winding in response to a rotation of the rotor being a function of the angular position of the rotor and containing harmonics, the said suppressing means comprising a pair of magnetizable members, the two members of said pair being mounted in alignment in two wall portions of the stator core situated diametrically opposite to the rotor axis and transversely adjustable relative to the mass of the stator and to the axis of the rotor, adjustment of the position of said members relative to the stator core and to each other affecting the harmonics of the voltage output of the rotor for the purpose aforesaid, and further comprising at least one pair of shallow grooves in diametrically opposite inner wall portions of the stator core defining said stator opening and facing the rotor, opposite grooves facing each other in alignment across the axis of the rotor, the configuration and position of said grooves reducing the harmonies of the voltage output of the rotor.

References Cited in the file of this patent UNITED STATES PATENTS Number te Rosenberg Nov. 29, 1927 Number 6 Name Date Blankenbuehler Feb. 29, 1944 Candy Feb. 8, 1949 Glass, Jr. Nov. 2, 1949 Ivy Feb. 21, 1950 Glass, Jr. Dec. 26, 1950 Bechberger et a1. May 1, 1951