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75 NSUIJATIN~ PAPER ,,_ By Bell Telephone Laboratories ]~.y If ~ No JO Affect of Sem~-condttct,ing ~gu~..r~s*on the D:LeleCfric Pr~n~rf.;~..c cuff Ce~l~llo.se Insulation- - - F. M. Cal ark. TO is shorn that when certain dielectric :I;qu~ds are mixed with certain se~i~conducting liou~ds in t7ariolls -proportions the power factor of paper irlsulati.on impregnated With these mixtures goes through a ~ninimum. For examples cresol, a semi~conducting liquid may be ~.ixed With tricresyl phosphate, ~ dielectric. The pouffe factor of Kraft paper insulation impregnatedv?ith SUCIl ami.xture is Roust Then the blend comprises about 25~c cresc,] and 75% tric-resy7 phosphate a Clark has st,..~died ~ number of other mixtures of semi-conducting and dielectric liquids and finds that minimum dielectri~c.loss coincides With a resistibility of Pregnant in the region of ~ x 107 to 2 x loo ol-~-certimeters. The dielectric constant of such r.ixture is high. Hence capacitors made With impregnants of this sort have a higher ratio of Gc.DaCit.s,7 tC physical -old than those impregnated With chlorinated di- ph=.ny3 though power factor is higher and dielectric strength 7~.~er. :~Ioreover9 it is possible to use a single sheet of tissue With these ~r.ixtures and capacity is not dependent upon the spacing of metal electrodes. This latter, it is explainedg is due to the impregnant acting as a l~o,uid electrode arid, therefo.reg only the paper thickness is the determ.ining factor. Data are presented to shop? that the power factor and capacity of this new type of capacitor are stable With respect to ten- perat~lre change and under applied potential both continuous and ~.nte.rmittent . * Revie~r~er's Note - It is suggested by some authorities that liquids such as those __ _. ~ _.. i. . .. - .. .._ A. . . . referred to in this article should. be termed more properly Peal: electrolytes'. Cationic Exchange Reactions of Cell'~ose and. Their Effect or Insulation Resins Cance2 - XO ~0 5h1~1~ChO This. is a rather extensive investigation of the subject, and much data pertinent to the requirements of 'Roth m`-nw~acturers and.users.of condenser paper. are rer.,orted. it is this revierer's Clinton Chaff the title should read cationic .. . .. exchange reactions of paper rather than cell.ulose since that it is the material used in <~he study and there is considerable evidence indicating that these re- '' a-ct~ons occur in large part in tile non-cellulosic components. i`.Cr...Church's own data support this inasmuch =$ his most '~ig'nI,y purified papers show the Jolliest cation exchange capacity. -using s eve rat types of paper, cationic.exchange Was effected by saturating With dilute acid to,,incor~orate hydrogen ions and displace other cations. Alter Tunis the samples Were r!asPled free of acid with distilled Maters in a Similar manner papers Were treat=,6 ~ith.dll~lte soDl~ri-orls of salts of sodium, pc~tassiw~ 9 silver ' ces ~ um 9 magnesium cad cilia, zinc ~ Atriums aluminum ~~ ~ ~ ' reaction is ably. iron to introduce those res,rectiY;e ions. It Was found that the reasonably qu~ntitat.ive and thing the caribous metals are retained b~-r the paper in proportion to their atomic height regardless of Nra.lence, ides flee same not ber of
76 atoms P.re held by the paper '..hether they be uni9 cii or tri~rclent. 'lichen samples were Dashed free of excess ionic material, those saturated v.ich .h~id.roger~ ions had the lowest DC resistivit:r (~neasurec] at 100°C)O TJnivalent; ~net.al cons, scd~..um, potassium cesium and silver were me: and these -mere followed by the !,ri:Ta].ent ions, aluminum and iron The highest resis-ti.~rit~r was observed ion those parents treated with the d~.va'ent ions, magr~esium9 zinc9 barium and ca~ci~mO Of a].] the cations reported calcium yielded the highest res::stivity Roth barium a ver;. clock second. Resistivi~y of papers treated -~.~ith these cations gal 6 to 7 times Chat of hydrogen ion saturated papers. DLetalized Capacitor Tests3 - Philip Codlev and JO Co Pa~sbau.~h . . . . .. To determine the quality of tints type of capacitor Chic' is self heeling it is necessary to count the number of arc covers or burnouts ,.7f'~iCt.t occur a' various voltages in a driven time. Apparatus foil such tests ~ s described in detail . Some data are given to shot the number Of arcs 7.7hiClil OCCllr in metalized paper capaci~o.rs as Voltage is increased ste~..i~se. Also some mea,~arements firs gibbon of the relative effective dielectric constant of metalized paper as compared to that of paper alone. Eater Ca~=c~tors Contai~hior-~na-'ced Im~re~nant;s - Bene.fiu~s of Controlled Oxidation or1 the Papery - D. A. Sean When I::raft capacitor tissue is heated in air it is shorn char its .nsu- lat~.on resistance inc~ea.ses markedly arid. ifs power factor decreases s~ghl~'icar~tI'r. This is true of both unin~prc~gnc ted caper and -paper imp~reg.~ated v?::th chior~r~ated dir?henyl subsequent to heating in air. Tndeed the effect on povaer factor is mo:re pronounced In the ~ mpregnated sees. Oxygen is e.s,sentia] to bodice th s change since heating in a vactlur.. ;~.s li-,,f,le or no effect, on these prone. Peso '~ertai.n papers which had been balled. in air were sutsequentI-j~ £~tu-=ted with moisture at 100~ relative humidity. After this they Here vaci?=n doled a,ac) impregnated anci Were foment to have retained the higher insulation resistance and loner pcr`?er ;~avctor imparted by the baking. This indicates that Ate effect is no+, destroyed by sub- sequent moisture treatment nor is i.' due mere:l.y iG t~iorou~ d.xyingO Tile reinfect :3s shown to be progressive with increasing baking cemperature to as higI? as Cloth maintained for 16 hours. However, serious im?:ai~me::lt n mechanical -rro~ex~t~e~ were noted in papers heated above 150°Co In Vies city certain theoretical considera- ticns the author suggests theft. not only is the paper improved per se -6u.t ~t Day also be activated in a manner to i.~n~,nobilize ionic material in the ~npregnant. The process has keen employec7- com~erc3:ally for several years. Parers as D: electric ~nsul.~tin:Materia~ s5 - Am. F;~a tarry nO This is a descriptive article c'ealing with the insulating properties of untreat,ed papers and papers impregnated Title resins =..~axes and oils. Partially acetyxatecl papers fire also dis^,us~sed. In general, oils used in p=,.~er serve primarily to protect the paper from moistures Special resins, ho~=ve.r, stab~2izs and accentuate the insu3~tir~g proper-~ies of the paper. A r:~L,nter of tables give the propert~-es of insure Eli ,~g rnaterialsO
'l7 A Item Graft Capacitor P&pe'6 - H. F. Mi]~ler and P. J. P:ocl~ins A modified Draft paper is described which when used to make chior-~.nated d~rheny, i~r~pregnatec~ capacitors results in a significantly lower power factor than tilt fold orc~inary gruff capac~.tor Missile. To make this paper, regular Kra'>t pulp is -~=ted to remove source of the mineral constnuuet~ts such as calcium, magnesia and iron. Tannins are extracted and ap~rc~ximate~y 20,~; o:E bile hemi-ce]lu3ose content is r<;?~o,Ted. Tnci.dent to the purification process 1i.gnin is also remo~red9 however, this const,-~tuent appears to have little or no effect on poser factor. Tlie greatest decrease in power factor is obtained through re~nov~l of a portion of the kemi- cel:luloses. This step must be careful By regulated because :if too much of this con- st,ttue,~t is removed an increase in cower factor occurs even to the point where ~t is greater than that of the unpurified pulper. :~-t is shown that when paper its pros classed to the cptimu}~ degree a decrease of 45% in power factor may be obtained. flue autI,ors slate Pilaf because the Watts Toss of -this ~iod.ified paper is louver than treat; of standard paper, a lower ratio of case area cf capacitors to Bear of raring can be to].erat,ed Edith the former. This s~mp~ifi.es capacity, housing design =~d per~l.its building larger units. 'the Thermal' Ex~aris.icin of Insulating Papery - A. ~allraf~ An apparatus for measuring ate thermal. expansion of insulating paper is descry The paper can te stretched in the apparatus In a definite clay, dried in a vacuum and kept dry. The -~resll-`ts of such measurements ar<a reported.. r'~erm.~3 ~ro':er-~:es of ~nsu].atir~g mcL~eria:l fire c£ techn:~ca] importance 'because of ye heating in the cable prodLuc~d by current. Aging Tests con Class A Irls,':lationg ~ A:1:EZ Transformer Committee. Resvit.s are reported of ~ series of cooperative laboratory aging tests made on oil impregnated manila Paper sealed in glass tubes. Impregnated paper strips rerc heated at 200°, 120 and 135°C. Samples mere removed periodically and t`~s+,ed for tensile strength and fo].ding endurance. The ?,Glor of the impregnating o;1 and its acid. Here also reported. at these various periods. Some measurements o4'-;;ear strength, poker factor and specie c inductive capacity are also included. inhere is some deviation in results obtained in the four different laboratories cooperating in these tests. After aging 5C Weeks at 100°C the highness tensile strer~gil' reported is at out 93< of original and the lowest about 80,<~. After aging 2; ,:~3eks at 420°C the highest tensile strength reported is 57% of original and i~?~t iS 40!~. After aging 30 ree'cs at 335'~O the highest tensile strength reported is 25- of original and lowest Is l.5~c. Tile Frobable BreakdoT.!n Volt. of Palmer Dielectric Csnacltors9 - .~-'am~..lton Brooks. This is a statistical Stilly of 1'co~lduct~ng particles' in capacitor tissue. ~+ presents are analysis of a considerable amount of d=l~ on the dielectric strength of multil.ayer paper capacitors made with 0.5 miff paper imr)regnated with insulating oils The clutilor feels that 'llis 'fork ex~l3~ns, at lest in Darth the causes of dim electric breakdown of paper capacitors :n so far as conducting particles are ins valved. ~creover9 evaluation of the effects of redacting the t~ic''ne~s of simple sheets and increasing the numb el of layers is ~aci7:ta-t,ed and. the ad-'anCage of further reduct.icns in Acting Art cites in capacitor paper can be studied and evaluated without the necessity of a.cc'=u''ating field experience over a long period.
78 . BIBEl.OCRAPHY a_ General Electric Review, Vol. 50, p 9, February 1947. Journal of the Society of Chemical Industry, Vol. 66, p 221, Jeer 1947. Electronics, Vo1. 20' p 1.12' Apri] 1947. Industrial and Engineering Chemistry, Vol. 22, pp 1457-1461, November 1947 Papeterie, Vol. 67, pp 65-709-1°J45. 2. 3. 4. 5. 6. General Electric Reviews Vol. SO, p 20, December 1947. 7. Arch. Elektrotech, Vol. 22, pp 458-462, 1945. . . 8. Electrical Engineering, 66, p 919, September 1947. 9. AIEE Technical paper, 47-164; Abstracts ~lectrlca1 En~lneering9 Vol. SS9 ~ p 573 (1cI-7
