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OCR for page 75
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
OCR for page 76
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
OCR for page 77
Representative terms from entire chapter:
tensile strength
'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
OCR for page 78
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
