US2697807A - Motor control system for maintaining tension - Google Patents

Description

Dec. 21, 1954 E. PELL 2,697,807

MOTOR coNTROL SYSTEM FOR MANTANNG TBNsoN Fi1ed Sept. 15 1949 3 SheetSSheet 2 Dec. 21, 1954 PELL MOTOR CONTROL SYSTEM FOR MANTANNG TENS0N 3 sheetSSheet 3 F1ed Sept. 15, 1949 lN SATURATING WIND...GS.

To cATHoDES 5a 53 oF TuBS Sld53.

T0 TERMINALs 5977 ()F TRANsFoRMERS 5674.

United StateS Patent SYSTEM EOR MAI1TA11I1`IG TENsION Eic 1 e", Shofowooo, WfS., aSSfgoof fo CoHof-f1ammof, Ino., 11i1vvookee, vviSl, 3 oofporofion of 1)e1ovvafe A icaoon Se fembet ls, 1949, Se N0. 115,79z 4 Claims. CL 3187 MoToR CoNTRoL ThiS invention relates to a control systen1 fof electfic n1otors, and II1oTe paTticular1y to a tenSion contTol System fof 1eol Inotofs- In the pfocessing of Sheet Inatefial, Such aS in the Teducing and tempering of a long tfip of Sheet steel foHowing anneaHng thofeof, the fnaterial iS paSSed thfoUgh a Ini11and coiled up in a 1 oll on a feel dfiven by an electric n1otof. DuTing Such pToceSSing the olatefiaI is advanced to the feel by the movement impaTted by the miH work 1 ol1S Which afe uSLIally driven by another electfic n1otor. To inSure UnifoTn1ity of quality thfoughout the length of Inaterial dufing SUch an opefation, it iS Tequired that the n1atefial be coi1ed undef conStant of SubStanfially con stant tenSion. At the staft of Such an operation, aftof the material haS been thfeaded thTough the n1ill wofk TollS and anchofed on the coi1ing TeeL the Inotof driving the fnill fons is accelefated to SoIne pfeSet speed. 1)ufing Such accelerating pofiod of the n1ill n1otof, the Inate fial advanceS to the coiling fee1 at a speed vafying aS the Tate of change of Speed of the Inin Inotof. Thus in ordef to affofd coiling of the n1atefial undeT constant tension, the feel Inotof muSt be so contTolled aS to accelerate the coiling feel pfopoftionately to the Tate of change of speed of the 111ill lT1otof, ThiS alSo holdS tfue vVheI1 the ITin nlotof iS decelefated ffon1 ifs pfeSef opofating speed to fest, Such aS obtains at of near the end of the afofe Inentioned procesSing operation.

It iS a prin1ary object of the preSent invention to pfovide a feliable and accufato control SySten1 vvhefeby a feeHog motof Inay be regulated to affofd feeling of stfip fflaterial undef consfant tenSion dufing accelerating and dce1efating conditions of TnoveInent of the n1atefial to t e feeL Anothef object iS to adapt a knovvn type of contTol Tegulator fof a Teel Inotof vvhich nofInaHy functions to effect feeling of Strip nlateTial at conStant tension undef conStant speed advance of the ITlatefial to affofd the afofe- ITlentioned type of contfol.

Anothef object iS to provide IneanS affofding corfective action of the afofenlentioned confTol Tegulatof in Telation to the fate of change of s )eed of the n1otor affofding advance of the InatefiaL and Znother Inore S ecific obiect is to dofive a contfol sig na1 vafying as the Tate of change of speed of the If1otof affofding advance of the IIlaterial and by Suitably aIT1pli fying and tTanslating SI1ch signal to provide the afofe- Inentioned coffective action.

othef obiectS and advantageS of the inventio11 Will hereinaftor appear.

The occompanying drawings iHustTate ceftain prefeffed en1bodin1entS of the invention vVhich vvill now be de scribed, it being underStood that the en1bodiInents inus trated aTe susceptible of vafio11s n1odi1ications in feSpect of thei1 detailS Without depafting fTon1 the Scope of the appended olaiIIS.

In the dfaWingS= Figufe 1 is a di gfammatic showing of a feeHng Inech aniSn1 togethef Wit11 a control sySteIT1 therefof,

Fig. 2 is a diagfaIn1natic shoving of a paft of the control system Shown in Fig, 1,

Fig, 3 gfaphically depictS an electTical felationShip exiSting in tho paft of the contfol SyStem Shown i11 Fig. 2,

Fig. 4 gfaphically depicts anothef electfical Ielation- Ship eXisting in the paft of the conffol SySten1 Shown in Fig. 2, and

Fig. 5 shows a modified fofn1 of anothef paft of the contfol SyStem Shovvn iI1 Figs. 1 and 2.

697,807 Pofenfed Dec. 21, 1954 RefefTing to Fig. 1, it Shows a length of Inafefial 10, such aS a StTip of SteeL paSSing through Ini11 Wofk TollS 11 and 12 in the diTection of the affow and being coiled up on windop Teel 13.

The Inin wofk foHS 11 and 12 aTe dfiven by a difect cufrent nlotor 14 having a Separately eXcited 1ield vvinding 14 Field vvinding 14 iS connected acroSs opposite sides of a Soufce of constant difect Curfent voltage 15 in Sefies Wh an adiUStable TeSiSfof 15. Powef iS suppHed to the arnlatufe of II1otof 14 by an adjuStable voltage geneTatof 17, the a1-n1at11fe of vvhich is connected in a, closed loop vvith the arnlatUTe of n1otoT 14. Geoefatof 17 is pfovided With a Separately excited field vvinding 17 Which is connected at one end to one side of soufce 15 and at ifs othef end to an adiuStable sHde Wife of a pofentiometef TheoStat 18 vvhich iS connected acfoSS oppoSite sides of SoUTce 15. Genefatof 17 is pfefefably dfiven at a substantially constant Speed by any Suitable dfiving IneanS.

The vvindup feel 13 iS dfiven by a difect cUffent Inotof 19 having a Separately excited field winding 19 Field vinding 19 is connected acroSS the Soufce 15 in sefies With a TesiStof 20, Power is suppHed to fhe afInatuTe of Inotof 19 by an adjuStable voltage genefatof 21, the afInatore of which is connected i11 a c1oSed loop with the afInatufe of Inotof 19 in SeTies vith a fesiStof 22. (1onefatof 21 is pfovided vvith a SepaTate1y excitedfield vind ing 21 which at oe end is connected to one side of Source 15 and at itS othef end to the adiuStable Slide vviTe of a potentioInetef Theostat 21 Which is connected acfosS opposite sidoS of Sonfce 15. The Slide vviTe of rheostat 21 is prefefably n1echanically coUpled With the slide Wire of fheoSfat 18 So that n1oven1ent of one vvi11 effect corfesponding nlovenlent of the other, GeneTatof 21 iS pfefeTably driven at SUbStantially conStant Speed by any Suitable driving nleanS.

A bIlcking excifer 23 is connected across the reSistor 20 in a shunt Telation in sefies vvith a Tectifief 24.

zs vvill hefeinaftef Inofe fully be explained, exciteI 23 conStitI1tes a current fegulatof foI ffloto1 19 and accord ing to its output acts to vaTy the excitation of the 1ield winding 19 of the Inotor by conntefacting the excitation affofded by the supply SouTce 15. vVhen the output of excifef 23 is high, itS bucking action iS high and aS a reSI11t the excitation of field vvinding 19 of n1otof 19 is 1ov. The buckiI1g action of excitef 23 feacheS a II1axi IT1I1n1 value, vvhich becauSe of fectifie1 24, cannot be ex ceeded, When its output equalS the voltage acroSS the TeSiSfof 20. (ZonvefSely, vvhen the outpnt of excitef 23 iS lovv, itS bUcking action vvill be low and conSeq11ently the excifation of field WindiI1g 19 of n1otof 19 vvill be high. vvhen excitef 23 is opefating at high output vo1t age, TevofSal of cuffent thfoUgh the exciter is pfevented by the fectifier 24 to inSure against Weakening e1d Winding 19 belovv a ceftain IniniTnI1In val11e- Excifer 23 is pfovided with a SeIfexcited field winding 25 connected across itS tefIT1inalS i11 serieS vvith an adiUst able feSiStof 2o, Vhich vvindi11g supplies the necesSaTy aInpefe tufns fof nlaintainiI1g the 1ield of the excitef at any point vvithin itS fegulating fange- 1 UTther, excitof 23 iS pfovided with a TefeTence e1d vvinding 27 vvhich af oIle end is connected to one side of the supply SoUTce 15 and at itS othef end to a Slide WiTe of o potentiometer TheoStat 28 vvhich iS connected across opposite sideS of Supply Soufco 15. Also exciteI 23 is pfovided vvith a Signa1 field winding 29 vvhich is connected acfoss the fe SiStof 22 in seTies vvith an adjuStable TesiSto1 30.

Excite1 23, as thus far descfibed under steady state conditionS, i. e., n1atefial 10 advanciI1g ffon1 TI1ill vvork TollS 11 and 12 at constant lineaf Speed, fuI1ctions in a Well known Inannef to afford constant hofSepove1 o11t said n1ot() for 11oW of Unbalanced cuTTentS through said eactor satuTating Windings to thereby provide coTTesponding unbalance betvveen the rectied voltages Su Hed by said tWo Tectifying Ineans to said exciter iield vvinding.

1efeenceS (:1ted i11 the ii1e of thiS patent UNITED STATES PATENTS IIaTne Da Name Date ScheWe Apr. 11, McCTeary AUg. 8, StTatton Aug. 12, Paka1a Dec. Z Moyer et aL 1une 30, vvaldie Mar. Z, CTever IUne Z9 Bache1eT 1nly 19, Ioll Ma 16,

Hunt Iune 29,

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