Page 34 - konishipaper

...手
.
~e
.
~
.
ur!:，e~~.lpaq
.
e
，
d by~~
:
1魚 QKR 、 ~.p.p.ar 戸 n t1y.)d~ 一.i 、
~e~s I/!" '.1・
diameter constant. 士his tells there m工ghヒ be a 1imi，t".，fo，r tte，diameter..0f，.arc spot and it would be decided by an elec仁rothermal energy balance. The precise explanati~n would be.very much complica仁ed，however，a siI~lpl~ mode1 calcula一 仁ioIi. showni later could give a semi-quantitative explanation.
The current loaded by an arc is plotヒed as the func仁 ion o f the numbers of
，~i~，~ .i.n:r
~g・7・ T てtie''increase‘ofth"e"ri山nl:Iers6f'arcs.
3:;、:;:!r!? :3‘ ，"¥ : ) :;fl;二J，e "Th'e"an6de'are，s，p<?ts.';~r'e ver:y.;d.~~.f.er.e:nt，}fo中: 快oppoq c.3仁ho'd，e.， As.the
;;iL2);1千戸叫;:i ;1
current was increase唱 higher.than arCertain va1ue，th'e.s1ag surfa;ce ~ ~ 1t~ d
号下c
'
.ç.，
'
eミバ ~th
by 、t，hee烹pe，ri.ments.';by.a.;p0戸、er、sourceof
，The aþo.v~ res，¥ll仁s were
thr'ee'. . .:p1 1ase recヒifica仁 ion arld'the r~ppl
Here the ，power source 'ilas changed into a single phase potential己ha時edfrom0仁o10%(300V). Thecurrentloaded":byanarcasthe
:
~þ~ained
.
'of'applied'vo
pfpnqiprp， ofth，e‘日umber号 ofa~~;~ 戸己 s~own.~n.F:ig.~. ~n，.th.is0perati，.on，th.e
日
:~I time '
'
e
'
'
lt~ge
'
dur・ati6n o~~upied
p 0 s s i ，b 1 ~ .t h a t a b i g . ~ r c w a s . r e a 1 .~ z e d ' a パ t h e 旬 C ;d i a 皿 e 仁 e r s . b e c a m e 仁 w ic e a s large"as tho'se foi:-'three-phase'rectifica'tion'and'the c"t.lrrents loaded.by:~n ，arc indica仁ed almost ten 仁imes as high as those in Fig. 7. This shows that if the
b~ the ~mall~r
Q~τrenζwas
incte~s~d'and .
it.became、less
time durat~on .pf :.~i~~~argi時
t h r e s h o l d 'v a l u e o f ，;' f fi' o y i 'n g i n 't o a b i' g . .' a r :c '， i s s h o "r t e r 仁 h a n t h e c h a r ' a c t e r i s t i c time of a fine arc.moving into a big one，the current discharge with fine arcs
iQ?りd.'.ge
:
pqss.i:
Þ
i
~
.
7 ~itq
.
o円 tr円 siμOR
;
tq cR己Mgtarqs.
rthe.. cur;r'e.I}-t'"， even.if 仁he.¥larger， .~ロロ en仁
th.<1-.n the
p.art ylher己 the cPKFeatconsnic、teidlight?d iadim， whiEe
instant.~Y ~.~~仁 he
inside the body of th~
electrochemical reactions~!
o f a r c s ， h e n c e t h e c u r r e n t 'l o a d e d b y a n a r c .
slag layer'and.gas was produ~eti
1n ヒhis si仁uation we could not define the diameters
2.2.4 .Currentpens.ity.Loa'ded.bYianArc
F i n a l l y ， t h e c u r r e n t d e n s i t y d e f i n e d b y t h e p r o j e c t e d a r e a o f ". a r c s :' a r e
ohtained.an仕 shownin Fig. 9. ..The'current・densitiesェseem to，be proportional
arc; ，areas..The，~h.own
、 than.~~hose' foiother'cas~s， ・because the'arc structure.is quit'e.different'from
to the pr，?j~cte民
t h e a r c a r e a a n d f r 0 m 5 0 t 0 1 0 0 t i m e s 1 a r g e r t h a n t h e .v a 1 u e s ; d e f i n e d ib y i:t h e electrodeSurfacearea. ThevaluefqrRIleS]TagOflQZK2S04addedislarger
thos己.• for others・
diarieters of which'are from 0.5 to 1.5 mm，w~'ere the discharge might occur from the surfa手e of She，cavity，' while. th'e ，other casys. .give the-:'flat.'arcs，and the d工scharge occurs from the:pr.ojected s'Ur'face.
白白.，
• . • • • ・1 ・ . ・!il} ユ. .!i
3・ :Theoretical Considerations. .¥:r .As.仁hesecond.!part，asimple:cathodear.c.model-..is.:developed'a.nd: co~pared
";with'，the: exper~mentali..results. ，
.'，") ;:.r.。
Th~ arcs in thi~
case have 仁he pinho'le "structure， the
val，u~s
3.1 Ca仁hode Arc Model
The cathode arcing area is div'ided into four regions'as shown in'Fig.lO.
RegionCD;
Region妥( arc column region in boundary lay~r- RegionQ); arc spot region in slag surface layer Region4 homogeneous discharge region in ?lag layer.
1n th.is'simpl.e model，thecurrent stream line is considere.d a.s exp ，~nding rectangularly from arcing regions as shown in Fig. .10 anq all th己:values are
in、仁te:、巳ropSSectionnor-mal‘toy axis.
忘れ :I'he';diame，te~.sl..O.g t，hesetom.oge日 ou，s.regions!，in.the;bOLl:ndary，.~手yer， ，Dd'and!~he
These are 'as:"，. ・ 岬 . ・ 、
oμ平i.for~
hom9gen~ous
discharge region in boun.qary layer
ι.651
て ectificat~on
in which
was within 5 %.
around th~re 目 by the
are.the.current.density'based.on
.，
-l ，
t
r ，