ML18101A228

From kanterella
Jump to navigation Jump to search
Provides Recent Ltr from Charter Power Sys Battery Div Supporting Values of Specific Gravity & Float Charging Current Incorporated in Request for Amend
ML18101A228
Person / Time
Site: Salem  PSEG icon.png
Issue date: 09/13/1994
From: Hagan J
Public Service Enterprise Group
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NLR-N94169, NUDOCS 9409220259
Download: ML18101A228 (24)
v • d • e


Text

, ...

' Public Service Electric and Gas

-*- Company Joseph J. Hagan Public Service Electric and Gas Company P.O. Box 236, Hancocks Bridge, NJ 08038 609-339-1200 Vice President - Nuclear Operations SEP 13 1994 NLR-N94169

Reference:

LCR 93-27 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:

SUPPLEMENTAL INFORMATION REQUEST FOR AMENDMENT SALEM GENERATING STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-272 AND 50-311 By letter dated January 21, 1994 (NLR-N93196) and a supplement dated June 25, 1994 (NLR-N94108) Public Service Electric and Gas Company (PSE&G) submitted a request for amendment to Appendices A of Facility Operating Licenses DPR-70 and DPR-75 for Salem Generating Station (SGS) Unit Nos. 1 and 2. This amendment request would revise the 125 VDC Distribution sections of the SGS Technical Specifications.

  • Pursuant to telephone conversations with Messrs. Jim Stone and Peter Kang of the USNRC staff, we hereby provide a more recent letter from the C&D Battery Division supporting the values of specific gravity and float charging current incorporated in our request for amendment. Additionally, PSE&G confirms that the subject 125VDC batteries have sufficient capacity margins, which take into consideration IEEE 485 factors for aging (1.25) and temperature (60°F minimum @ 1.11) to meet their required duty cycles.

Should you have any questions or comments on this transmittal, we will be pleased to discuss them with you.

Sincerely, Attachment

--- --*-- - - - - - - - ~- ---------\

( 9409220259 940913 *

. PDR p

ADOCK 05000272 PDR I f\OD' I I

  • SEP 13 1994 Document Control Desk NLR-N94169 c Mr. T. T. Martin, Administrator - Region I
u. s. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. J. c. stone, Licensing Project Manager
u. s. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville, MD 20852 Mr. c. Marschall (S05)

USNRC Senior Resident Inspector Mr. K. Tosch, Manager, IV NJ Department of Environmental Protection Division of Environmental Quality Bureau of Nuclear Engineering CN 415 Trenton, NJ 08625

REF: NLR-N94169 LCR 93-27 STATE OF NEW JERSEY )

)SS.

COUNTY OF SALEM )

Joseph J. Hagan, being duly sworn according to law deposes and says:

I am Vice President Nuclear Operations of Public Service Electric and Gas Company, and as such, I find the matters set forth in the above referenced letter, concerning the Salem Generating Station, are true to the best of my knowledge, information and belief.

Subscri~ed and Swo/\~~~"~:fore me

.... this /3th day of~111 jµ11._, , 1994 c~~batL4'-

N~ta.r¥ Pllblic ~Jw Jersey My Commission expires on April 21, 1998

Reference:

NLR-N94169 ATTACHMENT 1 LETTER FROM C & D BATTERY DIVISION

  • P.2 AUG 17 '94 17:50 C&D PLY MTG

'C::l:t

  • I>> 3043 Wallen Road ~. -

CHARTER POWER IYITEMB Plymcu1h Meeting, PA 19482 Telephone (2iS) 828-9000 FAX (215) 834*7308 16 August 1994 Public Service Electric & Gas Co.

Nuclear Department P.O. Bcx238 Hancocka Bridge, NJ 08038 Attn: Tim Johnson Subj9ct: Salem Nucl*ar Generating Station, Units 1 and 2 125 Volt Safety R81ated Ba*rllls Model LC ind LCR*33 tor Batteries A, e. and c Gentlemen:

The fol/owing diacuaslon describes battery conditions with raga.rd to Its state of charge and operability status, From an operability perspective, the battery state of charge is defined as th* charged condition that will allow the battery to nave sufficient capacity to supply design loads for the specified period of time, to minimum terminal voltage, while experiencing specified environments.

The discussion will be limited to charging current and electrolyte strength as they relate in determining battery operability as described in the proposed Standard Technical Specification (STS) for the Salem Plant. The state of charge of a battery can be determined In either one of two methods provided in IEEE-450 and the STS. Ons method uses specific gravity. corrected for level ancJ temperature; and the other uses a stabilized float charging current. Some characteristics and limitations of each method are given below.

Stablllpd Roat Chtcqlna CWr!nt When fully charged at a stabilized voltage and temperature, the LC/LCR*33 battery cell, depending on age, should require between 250 and 500 milliamperes of charging current to maintain nteammended float voltage; and between 700 and 1800 milliamperes of charging current to maintain recommended equallze vcltage.

Stabilization, however. Is often difficult to achieve be.cause charger output voltage fluctuations, occasional short duration power failures, or periodic transfers between redundant chargers, resutt in a brief discharge/Charge cycle on the battery; and although the capacity removed from the battery is quickly replaced, the charging current for many days thereafter ls often much greater than the "stabilized float eurrenr. Since It require* approximately the same a.mount of time far a lead calcium battery to achieve charging currant stabilization, reg.rd less of the depth of discharge,

AUG 17 '94 17:50 C&D PLY MTG P.3

. C:l:I 3043 Walton Road CHAATIR POWER SYSTEMS " Plymouth Meeting, PA 19462 Telephone (215) 828-9000 FAX (215) 834-7308 16 August 1994 Page2 the battery would be considered fully charged long before the charging current reached a stabilized minimum value.

The charging characteristics of lead calcium batteries are well known. Basically, after a discharge of any length, the Initial charging current is high (up to the llmfts of the battery charger)for the duration is takes for the battery to reach Its float voltage, then declines, rapidly at first, but very slcwly c.nce the current falls toward milliamp values. In batteries or the LC/LCR..33 capacity range, the charging current will be well above nominal float values when the battery has 100% of the amount of the discharged ampere hours rel)lac:ed (Reference 1).

Lead calcium batteries have recharge efficiencies in the 98 to 99 percent range, therefore It Is easy to conclude that onca 100% of the ampere hours removed by a discharge have bHn replaced, the battery will have 1ufflci1nt eapadty to meet design loads at that moment, even though the charging current ii well above the nominal float value. For L.C/LCR-33 battery calls, a charging current of 3 amp1 or lass would be indicative of a battery in an operable state of charge.

The limltatlons cf this surveillance method is that a meter capable of reading small currents on the order of 5 amperes or less is necessary, and a specific charging (floilt) current limit be established for each partic:ufar battery size. This value will vary scml\'Vhat with age, voltage, and temperature, and these variations must be factored into the use of this method.

Sptcfflc Graylty, Cort19f!d for Lent and Teazpt11ture For constant potential, current limited charging methods which prevail in standby battery applicatlons, there Is practically no ga11ing In lead calcium calls to mix the electrolyte, so specific gravity readings are unreliable for determining operability unless there has been a very long period of st.abiJized float. (It should be noted that STS's originated at a time when both lead antimony and lead calcium batteries were employed in safety related systems in almost equal proportions. For lead antimony cells, voltage and specific gravity are batter indicators of state of charge than charging current. But today, the vast majority, if not all, of 1E batteries are of the lead calclum type.}

RS*89a

. . AUG 1 7 "94 17 : 51 C&D.Y MTG C::l:I

  • P.4 CHAATl'R POWER 8YSTEM8
  • 3043 Waiton Read Plymouth Meeting, PA 19482 Telephone (215) 828-QOOO FAX (215) 834-7306 18 August 1'994 Page3 This surveillance method presumes that all cells, once received and fully charged 1 will have an electrolyte level at the high level Indicator, and have been equalized to not less than the nominal 1peclflc gravity strength of 1.215 at 7"fOF. It also a11um11 that no electrolyte stratification (*pecltlc gravity gradient) exists, or that multiple readings have been taken to mitigate this condition. For lead calcium cells, specific gravity of the electrolyte,-without correlating the values 'l.lith voltage and charging current and existing performance margins, should not be used as the sole criteria for determining battery operability. Since they are however, we recommend STS Category A, B, and C surveillance requirements for minimum specific gravity be 0.005 sp.gr. leas the values currently established by the NRC. This would make the limits 1.195 sp.gr. for r.11t"(1ory A; 1.1;o Ip.gr. (cell) and 1.:200 ep.gr. (battory) 'ofl Catqery D: and 1.1QO sp.gr. (battery) for Category C.

These racommendatfons are based on several factors: (1) A fully charged battery with all cells having a measured specific gravity of 1.190 (due to over watenng 1 for example) wHI have approxlmateiy 93% of the performance capability of the same cells with 1..215 specific gravity. Thi* reduced J)9rformance would not lmp1ct operabllJty*unleu m1rgins for temperature and aging are exceed1d. Note that a fully charged battery with 1.195 spec:ific gr.vity in all cells will have approximately 94% Of the capacity of an identical battery with 1.215 *peaflc gravity. Sizing calculation* would demonltrata hew much margin actually exist1. (2) A nominal 1.215 sp.gr. battery with electrolyte of 1.1 EIO in all cells, but with nominal float voltages and a charging current lesa than 3 amps would indicate the battery i* l'GCharglng from a discharge, and the electrolyte has yet to fully diffuse. In thia sJtuttfon, the voltage and ch1rging current would Indicate the battely has sufficient capaeity ,(a11umlng temperatura and aging margins have not been comprcmlMd} to meet d*lign loads.

Thus, if a battery meets our reccmmendad Category C parameters, and hlstorical data demonstratea that there i1 sufficient capacity margin, then adequate assurance exists that the battery will meet its de1ign loads during the time corrective action occurs.

RS-8915

RUG 17 '94 17:52 C&D PLY MTG P.5 e

    • c:.1:1 e 3049 Walton Road CHART!R POWER SYSTEMS Plymo1Jth Meeting, PA 19482 Telephone (215) 828-9000 FAX (215) 834-7308 16 August 1994 Page4 By way of historical note, the IEEE Battery Working Group (BWG) recommendations to the NCR relative the STS surveillance category limits for spacirlc gravity were as follows:

CateporvA

  • minimum value to be determined by the user and the battery manufacturer
  • level correction unnecessary If no specific gravity gradient exists and charging current Is less than ( ) amps
  • for parameters outside the llmlts, the battery Is operable If within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, Category C values are measured and are within the limits; and all Category A and Category S parameters are within their limits within 30 days C1teqory B
  • minimum values for cell and battery limits to be determined by the user and the battery manufacturer
  • no more than 10% of the c:ella can be at the minimum limit (i.e., one cell with a low specific gravity does not render a battery inoperable, nor does it significantly reduce the capability of the battery to perform Its design function)
  • for parameters outside the limits, the battery is operable if Category C values and the Charging current are within their limits within 7 days, and Category 8 parameters are restored within 30 day1.

Category C

  • minimum values to be determined by the user and the battery manufacturer In summary. for lead calcium batteries the specific gravity of the electrolyte is important when these readlngi are used as indicators cf the state of charge and/or the need for an equalizing charge. But there are several limitations to their accuracy. and there are ether indicators that must also be applied when determining battery operability. It is important that knowledgeable personnel are involved in the surveillance, maintenance, inspection, and auditing of the batteries. It is equally important that experienced battery personnel select the beat indicatcrs for their lnstallatlcn to determine battery condition and/or ccrrectrve actions n1quired.

RS-896

AUG 17 '94 17: 52 C&D PLY lTG e P.6 CHARTER POWER SYSTEMS

  • 3043 Walton Road Plymouth Meeting, PA 19462 Telephone (215) s2s-sooo FAX (~15) 834-7308 1e August 1994 Page 5 I trust the above is clear and concise. If you have any questions, please call me.

Very truly yours,

~Ul..u.~

Granam Walker Manager, Applications Engineering

References:

1. C&D Laboratory Report No. 1430, 6 July 1970, Charge Characl$ristics of LCU*23 Cells on a 100 Ampere Current Limited, 2.22 Volts/Ce// Rschat;s Following Dlacharges of 2001 300, 400 and 500 Ampere Hours Attachments:
  • Reference 1
  • 5 Aug 94 Kyle Floyd Memo to IEEE BWG ** STS Topics
  • Technical Paper fer Publication, Assessment of Lead Acid Battery State of Charge by Monitoring Float Charping Current RS-896

AUG 17 '94 17:55 C&D PLY MTG P.1 e

Ill 3043 Walton Road CHARTl!Fll POWIR SYSTEMS Plymouth Meeting, FIA 19462 Telaphone (215) 828-9000 FAX (215) 834-7306 16 August 1994 Pages I trust tne above is clear and concise. If you have any q'-Jestiona1 please call me.

Very truly yours,

~~~

Graham Walker Manager, Applications Engineering

References:

1. C&D Laboratory Report No. 14SO, 6July1970, Chatpe Characteri11tica of LCU-23 Cells on a 100 Ampere Currant Umited, 2.22 Volta/Cell Recharge Following Di~harges of 200, 300, 400 and 500 Am,,_,.. HOUf'$

Attachments:

  • Reference 1
  • 5 Aug 94 Kyle Floyd Memo tc IEEE BWG -- STS Topics
  • Technical Paper for Publication, Assessment of Lead Acid Battery State of Charg* by Monitoring Float Charping Current Rs-e&a

AUG 17 '94 17:57 C&D PLY MTG a

P.2 M-43 C&D BATTERIES DIVISION OF EL'rRA CORPORATION REPORT NO.

. DA'rE 7-6-70 1430 LABORATORY REPORT Charge Characte1*istics of LCU-23 Cells on *a 1.00 .Ampe1*e Hour Cui*i-ent TITLE: Limited .2. 22 Volts/Cell Chargcn- Following Discharges of 200, 3001 400 and 500 Aiu1,ere Hours REPORTED BY: H. J. Schaetzle

.. ~*-

.APPROVED BY:

  • DISTRIBUTION: Messrs. Clqssey, JensenJ Stove1*., and Zachau OBJECT: To deter2nine the '~~ia tion in th~_specific gravitl of the etectro1J1L.

as mc:'asured in the vent well and at the bottom. of "the gravJtv tube *dw*hJrt 2. 20 z!Olts/c~ll - ctu*rent limited recharges.

ABSTRACT:

Three fully conditioned LCU-23 cells were given four carefully measured one hour dis-chages at rates of 200,,

  • 300, 400 and 500 amperes. Followi.ng each discharge the cells were fully *recharged on a 2. 20 volt/cell bus with a *maximum available current ouiput of 100 amperes. The speci!ic gravity of the cells was monito1*ed throughot1t the recharges by n1easuring the specific gravity of the electrolyte at two points, at the. top of c~ll through the vent well, and at the bottom of the gravity reading tube located in diagonally opposed corners of the cell cova1* a11d eA'ieitding approximately 7 inches below the-? liquid surface. The difference in electrolyte concentration (expi*essed tn* apecifto gravity tmits) between the top of the cell and the bottom oi the gravity l*eatling tube is shown in ihe f'ollowi ng table:

ico A~ a I 2. t 'D.~t-1. _. "'\::l !:l.""~~t.

!)ec- 14 :. I 8Jo ..,l 4co ~ =- f.i.f 7., '-

Se~ "' .... 3ol ~'

P.3

"-* *. . AUG i7 '94 17:57 C&D PLY MTG

'\,< *. . .. *~*

e

..a;;-;1i;**--.."*-.

. J,.. *,...

--.. .,. .-*-----1

**---**~ ~****~-*-*--~-***-*--**s;~-~ifi~*

AH Sta1*t of

..,....._ r""'--*'"""*'" ......_ __. _..,.~....

100% of AH Discharge .

r**-**----;-- -------t 50 Hl's.

  • 288 Hrs.

Removed :Recharge :Returned Charge Charg*e vw Tube vw Tube vw Tube vw Tu.be 200 1. 206 1. 207 l. 205 f.220 1. 206 1. 220 1. 211 1.220 300 1. 198 1.199 1. 200 1~ 21e ' 1. 201 1. 2~0 , I  ?.'17 1. ??() I

- 1*..

  • 400
  • 500 1.190
1. 183

-... ~

1.193 1.186

1. 192
1. 186 l.2d_ 1, 196
l. 220

. 1.192

1. 220
1. 22~~.1- 1. 200
1. 201 i;J 1 VW - Vent Well Tube - Gravity Reading, Tube

---**-** ____ ....,___ -,...~- ... -...--T~~~~ ........... **~ ----~ T . *- ~-

"":"':'. . . .. l ............. , *.*******. , **.

  • I .....
  • 1.... , .. .. * * ** 1**.. .. .* r... - .. , . . . .. ... **" . *T* .. *1* ... , ... T ..
~**: ~:*f:

1*1-.. ...... .. .... .*1:::.

.. ** **: *::~.:i.~.:~.i**:~*~*r:..:*:: .:...~;'[:*:;~ :::;:~:;~ :~!.J:*.! .:~~*~.:*:.: ~:~: !!~' *:~~: ~~:t :i*!.:. ~.~:: ,*::1::;.: ;~:: *:::*~ *:::;~::.:*

r

.  :.~j .. ; * *.- ....~.:.L*;: *. :.:..:.~ .:.~.:::.r~.!: **..!..t: ,:.:..:.~. ~ .... ; ....*: **  : :.. ,.::~:L.::.d.~:-::  ;:.;.:r:.::: :.;:..:  :...:.::.;~..:;.,:.:.;.:  :.:..::: ...!.:*:..~,r:.~.:t:.;.~*:..-.:r..:..;..:..

..:;"*~*:*** ***i 1 c~ r.1~*~1:.:.:**:::.:::***~: .*:: 1 ::~:  ;;~.:rr-t....*r.tr,,*.:**:r .::..t::.: ::~!.*::: ::::r:":: ~*!:;t:*;~: ::*:~~r*,: ::~: :'.*~ :.:*:!"";

. . . . . .i . \:r, ..... J, *********** ,, ..... **:* .. i' i,;;*** t~ .*... ..** ..*.. , ****** ***:{****=; **!***1**** **;*!**** ,,,. ~****:: .. :~ ..

  • I* o * . : : , : ,..:.....: : , . ' ' - ..1' I~~:..:...:.~~~~~..:...~. ..:....::~).;..;.~:.:.,;,,: : : ,: : ... : ,' ~.:... -~~ 1~.~,. ~..:.:.:.~*-;.:. .,;~~  ;.;,ill'!.:.:.!....:...;:. *~~.l*.: .:..:.:. * ~:.;. * .:~'****I I
~*
~.~:.**

l ,0 , .

.* ... *,,*,*.::1'*:;r*.*.-~:~~~:~,: ::r:I:~!:. ~::~~:* ..:*': t.<J :: :;::f~i:.~ :;;! :;*:~

  • -*
  • 111 '-'**I l**o 1 1* *** t*l*ff II,,.,, f

~::::,'".::: !:.L~ :~:*! ~-~:t!~:~~

I** 0*1-. ..,,,_, .. ~I**,,, .. , -*11

~*;
  • ~ :~!~*l*:::::*
  • t~. P"*et 1 *
..... C
'> ............ L'" (;~******-- '""'"'of**** .,,i_i ..... ;,.,Q .. (11. 0 .......... ~1 ....... "*'~"--~.,., ... ***** ;.,,., .***.* j,,., ******** .:.;.. ::'..'

~ . . ~~~ *. ~*. w. ~::: ,- . :: :** ~:*: . :~:;:~:: ::r:.~ '?..i**: .~*: *. ~~;.;.:* "~;:: ~ :: *i~: .: *::;;: :~; .! !:-~; *.:-~ ;.:;*r;~: ~::-: .:rr;- ~~:::r :::~ *~:t= .~: :-.~ :-:: *t~-:""::~*,

  • ...............[ .... 1... 0 ............. 1..... .. 1 **: ***. , ...... .1.i ................

..... ......,. ................ ,............. J*:: ...,................. ..... **!**t""*l***'.1 ........ ...... , ........ " I * ..

t---- -~---- -"""-.......;.....w._......... "" ............-+-*-...-*

~ -- to--.....-___....._,,.,--..,

~1.- ,!. ~ .. /----...... , ..- *--~m- ....... .

---~**1'""'"

  • i::'." .. **1.;::;*l::;~1:.::~~~:.:; :::*:.~:*:::; :.:_*;1:;-:: -.:::l:.:*~~* :~i.:.:i.*;i; :.::.:)'::::1:::::1:::: *:::*:1:-t~: *t~.;.J;.!:.: .~::; r:~~*; '.*.-::f.*~;.1 I.

.. -* ',. ..

  • 1**. - .... r...... -**-!-- ..... r** t*r*! .** I' .. ~- *-: ' 'j. ~*- ***..* ~*** . . . . . . . . . . . . . . . .t1., ..*. -* ........... , ........ !............

~-* ~:.t~.~ :. ~~*-<¥;.~':: *. :~~1:.:**-~:~~~ ~~ .~ ~~~*=*-J~ =-=~~:.::...:-~:;**t-o~:.t~: ~.: *. :~~.:*'..:; =: ..:.:;. ::!~;~t -~*rr7::?. *t:f?fl~~~*~ t*~t?*§i .~f1*~~:n

~::*.~~.r.~. ~ ru.~~~1:.EP.:::=-:~:

~--- *--"'L~*--*

.. *-,.,,--... -****  :*:~.~.:.:.:::- *;::-:~. -- :::-:: 1 - ,.-..... :f,~~Y~:r ---.~--***,.,.\*

.. AR.'~l~r,1.~r~.:=: *- -*--**-1*...,.... ._;._.1.:1:.:~~ __.._ ;:~; __,. ._ "-** ;;:~:+ ---::*: *;!:~~ ::~:1:;~

.1.:.:*****o* *-~* .........., ..... ,, ...... "I*~- ..~* ......... , .. *r,.......... ,.~...**- ..... -**** ...... *-** ... ,........... .

  • -::.: . .. ~.~::*:::~:

.... ,.1.;*.:,*~""v.******-**  :.;: ~-:..:..r.::.~ :~:.: ..::.:.; *~;.:.':" ';:": . :*:*:.:* .::: *~.;~ :'* *~:~*~:~*: "'. .. :*.;it.111:::.~::-t ti::! 'i!T"., :..:.::l.:::;::,* ~*::* ... -.. ~

.... - .... ....... o .. '!'.t *** o ..... ,.... _}...... -.... ful....... h,.o.-..... o ... ;1 .... 0 ...... :0 ....*"..1 ...... ,, *.* *****~!+/-~!'*'**;*.::*:~

  • 1 ~~*
    • .0 . .~*: ::-~r:;~*p*~~:£~* *:.1r~ .7~ ~:!; ... i-~: ~~"~?:: .!!:~~* ~:~=r *:::~::Ii ~; ~;17f~: .~ ~: *s; r:r: ar ;:tr*~ D='
        • ltj**""***~ ......J,..... .......  :!~**** , *. ,fi:......... ***** ... p.,~*-*1** ....... 1.:1 .. t ******l******t**** __ ,:i; 1of.l', ......,,,.j .*. ............ /.. ... .:1 ~

,Ls .....

Lt~1tu~0f- strni.~*~;G~tiir ~i.i t~-~:ii: ~i-fj :uH.r@f. i'fii n.fi. trr£1fi~r~~lii~ iH&~;r4:~~frtffii*

1-***Ara*~s* 1s-r*10H!:~ 111~~:**** ~........ _ ...... 1 ~*;l;,.r: ..... , .. , ............. c~'*'*~*t 1o**!Ps

~it;~ Jii1 k1i

  • ~*;.:* ~:: ~11  : , *; ~ . r* ._,;~:.*: ~~
  • :.::::-.. .; * * ~.'. *~*~: i ; ! ~: .:,::a:.:. :11 * . . t*; t:. .! ::.; .;? : ~ "-"' *, v. .._., rr. ..... ;*~: :.!~:. ~:-..~ ~ ;:, *. ~*:..:.:
.r*-*r*** ............,. .. ***:.r'*****' ,.

....... -<*-**1* ....... 1 .,.,...................  ;..i.,. *..* ,.,_, ..... ~ ... "'**t ****~** ..... :.t~:.*~ .. , ......... , ..........*.. \.[ .......... - --*** ..... ,. *. ,..

-*-~*w.-- 0 ,..-1>-~

... __ .. N. * - * .... ""'~'""

m-- *- ~.~ ... --*~ t - *-- ... *

  • r:

),_,. *.1 I " I""' P91 I

......... ,0 *---.....

"1* *

  • t"'"

'"'l"I'

-II f'I loliolo*--1

............... ~

°'. . . . _. . . . -*

-.;t-*** )*-t ... 11Q***~fl*IH'**too*o** -~

  • a .. ' *-fo*

~-* ... --

... a.*t***I*

',..,..,., - *

  • I *---~*,&. 'I",. ....
  • t' I'll tPfll
  • I* 0
~******~*- **to*--***~....................

r ...,, *~l't ..... '"'*1 v~****

I 1-...i I

..~.

1 "

~""'<.ME:.

~-"

I

-** ,,.,,~, Ao~l' 11**-*

,I,,.+* ,._, *

'fl?'i~**i1't*1

  • '- *** ,,. 1 .,.,

11i1.t

~ .. ~

---~ - - - - - - * *-*** """--!" _ .... -~ - - ..

, .... ; .*. r:* ---**

.1:.1111*.t*f*I*** ....

\.P*-** ~- .. ****--** -*- ***- *--~**--* ...,. .............

. . ...._""'--"'****L" J1~*r ***If**...- *.,._.. ..,.,~!*** ... ~ .... ,._l,Of* I l:'I'~*-"'"

__ *--* .........,***-** *r*1

_1 ... -*......

':'°"

~-**** ,.. ... , ...... ----J- _,_ ............ * - .,...*---

    • 1 *1~ ! * ' l l \ ....11'° ........ "I"*--*"'............. ~.,,.,,
-*!~****I.,_,..,**~ "'If,,.,_,.,. ,, .** H .

.** , .......t:  !

,., "*** I ' ' ,., " " - " ' " * . , o .. --t~ . -!" **" **1 ~*~I'"- ., ...... " " o " ** -:*.+:*" '"~' ., ***~ " t '"'* IAI *~ ** *  !*, ..,......,. "-' **-..! oJ *~* }**;,, ***"; 1. **1*0* o-J f N' ,.

o ~*~.-:.:~;  :~~-;~,... ~*~.; ;;;; ~;;;.-:~;. ~: . ;: *~~~~ ~~;; ~*;*;; '.~;:. ;;*;* .;;;.~ ;.: ~~I~;*~~:. :;.;*:*;: ~: ~ ;;; ~; .;*~.;*:*:~;-~; .:-.;. :;;: *~~;*; ~;~;~ QC'

.. . ;;.. ...... _. ' ....F-**~-:.r~:........ -***** ............................. *'*~ ... t ........ c:* ~-.".\ *...,. .. ""." ,.....,..... ,;.;.i *f *-'"* .... 1~ **. L

~~~r~=-. ~- . :.::* 1

    • * ~~:=r.~-s!.==:~ ~: ~- ~ ~~:~ ~:-:- ~*
    • . .: *-:::: -~ *~*r~,~: .r. *.:.:. ~ .:::~~-:--::-=*(_:r: Q.-~ **~: ~~~~~:tt il<e
  • n*., ** 11 . - 1 *' 1 I I * ** - * * *** * * .. - ,* **** t -$~~ *rd* ,,. * *r* '"' :t .,, f *- -~* * .,,. .,_.In - ***,..\,I I, I 9111111 * * ,
  • 11 t"**"' *, ~ f

... _ ... *i*r'* II -* ..... **r!* .......................... 1, . . . . - .. , . . . . . ,_,.,

"' * *,' . -* ***- ~,.,,..,,, ** ,I ... .

_...1~.. l.fl..... . ~. 1 ' '....... .. 1.................

_..... :..-... - ......... **-* ,~*. ,.......r.,,*I ........  ! .. * - * .. *-* , __ , . . . . . . . . . , ...... r-:--... ...... . ~-  ;;; *(:*-

  • -***ftlo,*I I\)~****-****-****... ** I ** ,

.. .,- **t'I**"- -

~-*** ..............

1**- ... _ o*All

~ ..... ,, *

. ~~**** ****'

t ....+***_........... .,,_ .............

.... ~.--.-- ~*~ ***-* ,.,_.~

, 1, 'ff ........ II

-,..n.. - ... ****-

..... ""'\' ..,.,

  • - ~ ....... ~. ***

~ r.

i .*** ['._""' ....... *****'""I *. ' ............. rn** '-**lj'\l ::t: oo( ('Q** 'I) ~*

  • t~****.....- . ,..... . ,. ,. . . j ... - **...!.-**** ........ , .......... .......... ,..... *- -*-**"-"*1"**** - 1.*

~~~~ :: :*::*~~E- y -~;- *~;*;~:~}.;;:;~;;~;. f~=r.F::t ~f I. -~-:~*~-~~ 1 z

. ~ *1"' -~~ :i r

!--** -* ....... I* *4**** **-I.:""'"'"""***"' **-*'* *** *** :r:. ::.,. f;t """ "i::j ""' fi.f~?r tf.i**-**l. ** * ********"

.. ., *- . ~.; ::~\::: :~* ff~~'. if:*~; :7f.; ~ :> o*il 1***.. ~* 111 0::.. :i: *.

... *.~:~.P*** ,.,.,,.,,, ...... ~ ........................... I*,:..:,***',**** , .*...** J, ..... **--~ ***~~..:..._:.*-.-*******~.....:.:..:.:.. o.~'""'-'~ *****

~ .......... --* ............. _, . . . . . --- *-** ..... *- --*r** ....... "' - ......... ~- ., . -~ . . . *t" (l:f7E ~

Fdf4 :~*:::~: ~ !.~*~~: *~~.::-::~¥::~~ '#~:~~~~*~ ~*~~:rm:~~U~ '.~: i'~~ F-¥ [t£4.~~::w*~*~_::; _111.g~ l>.;~

. **-*-'-*' -**-* * . ! ........ .. **1* .. ' .j .. , ** -* ........... ¥of:t:I

.... :*;*~;r:- ..-;*;::*. ~ ~*-  ::::--~; ~:

.*:.:.; -*****-~-*~  :* :: r: i:*:; . :::-::* ! : : *- ~:.:. ~ ~: *\ . ;, *:*~:: :: :.. I.~~ 1: :;.. ~ : : : l.~~:. ~ ~*:..! ~** ~;: ~. ~ -:...I. ~:;

~*<~]* .. ~***ff~ ......:J ..***lli'"r .!.:::.;I g. :c *. :.,* . ~*-

- --""'r--1" ...... -*- ,._., *---..i __. . . . ,._ 1- .~:-.... * -::-\~

................... - *--*~ .....- ........,_ ..... ~ ...... :t*-.. **p*** .............  ! ...................-.,.* , *1r11

, ....... ~ ~****

m . -....*~**r-I* ....... I :.... *---*** .... r-**** - N'** 1*r* ,...*

      • -*"'**r*'-" ',,,., .* , .. **** ...... **** ../" ... "°""t' '" **u!""~, ,, *** \~*-*¥ -~*

-*-1-............. ... \..... :l: .....................,.1,f"' " ......... ..*1-***1 ... . -** ,,,,

..:.:.:.~.:.: .......::. ~ .:. :..~*.:.. !!..::::!. -* "~*** _::. .:.!...'..!: _:_**r, -~-*..! ~ :.=.:.t ~-=-**~ I' I I.... *.. ~~ ***~:. : ::: .... :-.:. .* :*J;;**r.;.~,.,~ ~*y -~

.... -* ... ...... .......,., :c...;:;

=** ........... -.... ,.t~+/-*****-** ***- ..,.-:. ...,........... 1--...... *1 .. -* ...................... **r** -- .. -*~* ,., ..... .

~.~ .. -;.::.: :*.:.~:~*: * : :: : ~:;:-:. ***-;:_:l: ~ ~ :;.~ .!.t;: :*:::. : ~.:* : ..~~' ~-~::.: ! . * ; ; r:: ~.~: ::~ r : .;..:;*: ~-=== J .. ! : *::*:; ", ** *

  • ., ---** ' ..** 'jg"""" " -""' ;. '... ...!. " --'1---- ... I .... ' .. ' . } .. "i-*" ' :-:...:f*:::*: .... '" J, '~ :r M~.:

~l: ":'~ * *** *-* ,".I":':"':'~ ,..! *. -,.,.,., **"' ,.,, * '"'*I ".'..... *! " .. ,.. . '** * '*** * . ,. ** . ',, ' - -** -::--*::'":";":°'~-s*'°'r.

"' *~> (()

~ I..... ***~* ..*

I* ...-**__j_

- ..1.1...* "'**-** , .... -*** .............. ,,_,, .**.*. , .... *****t*:*-- .... ""'1" .. *-*........ /, ... ,.,... (.) ' ,.*..

~~~:.m:: .:~.=.: ! ::.:!zy~:-:-;

. .  :.:::: .:~ .;:;:_ :..:.:~*.: :; .::;;*::~;:~.:_: *:.:.~.::: ~. ~: .:.:.£. ~;;.~ i .:::.- ::::..;.~:i:~.j.~:: 0 .. *.* .. .:I :~~

  • -*f*"*"" ~-**-* ........... **"-J"'"' ..* *-*- ~***}* .. **-i:fff' " " ,.,7t. __,,, .. ****!~
..:.:,. :;.~:.~
.::~1.::-::; :~::..-~::  ;:*:.;:.~;,~ :~.:.  :~.:: :~.;: *~.:,,.

. . 1 ..~'7 :*:-:.::.. ::-.:..~~:~ *::.::.~~::!'*:=: . * :;  ::7: :.:.1:: ::

,... '/'"._. ::*:.:..:: :r=:!1.:, ...._ :f'*...:P, -f .::..

............. ,; .......... , ' ................ ,,,,,, **---****i.- -* ....... a ....... *~** ***~ ***** , .......... ~ ... , ":ll****t.:-.-- \iii~ :c m. . . ,

0 "' "~,!~f'" r.:r:;:i*z-~!"f

.,.._.,, .. ,._,, .,*Z. I . ,, .,_ "J ooM*** * -......- .... !, ***! ***o*f**** **p* -** **** *'*** ***"

"".!i' "" ~iii@;, if i'=s=' *:*::: ~;r: ,,,, ::; ,,,,, ""!.; , ,r ;;;; ,,.,..,f-... *** '""" ,,,, * -* ***** -4 t"' ~ ~. *:* -1 en.~_:**

~~.:.:t.-:t~ :* *~;f:* ~** ~~* = ~~t~:*:::* :.s..: !.;.; ~ *.:: ~==:i*: ~=-=~-~i::* *~: ::::t. :-: :- :~:~.c::~*: ?:~::;? :-*~~ 1 ::7.*~ .;:: ~em;.,,,. .. ;-;~

C'1 ;:****** ,1, ****

--*-t:""". ***~- .i * ~ r

  • I *ti .... ~.... lo ***-* * ** ..,_ * * . ** '"""*' *1***1 ... - * * * *..;;._ ,,., o * '"' 11** '6. *.,;,:.;. '0" * ' I ... o *
      • i!"* 0 .-f ~* -*.::.

I I". r~ *..... ---.. .~

w " . . . .- ***, "O /*J"

  • l . . . **"-*-******-" -**~~....................... ***- ............... *-- . -.. , ..'**~*-*

--**t""' ...... '~ ..... _,..:.r.~........ ****** ..... ""' .............. "" .......

,. -**- "'~'L"""I.'](')

0  ;::::."*~~:.:  ;.*::N .* ~ :*.~ .. r::---*t:..::=: :;!*rui:..:*;:*; :.;::*::::.: ;..:.::;;!; .. : ~.~r. ...:~.;..~ *.::.::.:::~:-:;.i::  :~*.;.*:;::;~i~;:r:.!*::1:-1* w :t ~

    • ~*ior-*' .... , " ** ...... - .. ""!~ **-. .,.f., "'' "'***'-*** " " ...... ***** "'" **"*l***P* ' ** ***-""'~'"" i;!.. c  :< o**** l r*

6~

~ *.. ~~;-~ :~:*t. ~-=::~~:.::!i E ~:;~ ~~* .::::=:t ...... ~~. : :~: ~:: :.~; .~ *-::: :.:::::-\::~!E ...:~ "'r t:::., :;;:...........
.;
_,.:*:liP'r*I ..:.....:*

co "-***-1**-* ~ o 1 * .................. _, ...-....... ,., ....-r ..-....; ........ ***** *

'-~,:-* ~ ** , .. . *.::~~* 11**r'"-t**fll~A*~. ~~~** 1*~*l* ..,,_, n.:..: ..

    • ::: ~~*:~ ~-~~l:.:*:-~{*
  • 7.1 *m ........~*~**.;*
  • ~~..: ;.--**~ ***t*t**~:.:.;.m.-t.fl
    • ..:.::...:...:: :**-J ......,.... * ... - ...... *r-.... ,Q.::a ...t:JI::...:**--*..:..:..=. .c z-1'1

............ , ... , ... ,.~rl"':, * .,, **11*-.-***I~

, ... t, r* . *'11l'"""-**---* -** ....... -~----- ... '11:: ..._. *'!J- **** 1*-*r-*-** 111*1 * ***'-* * ** .,., ,._,,

........ -***- * *""***- ****~**!*'"~ *******

..  :-;1.~

        • **-*~ .. .. ~;;

- ..*****...-, - ** . ' ... - * ***** ................ l'ft ....... '. *** ......... ... , .......... 0 ............ - ..... ....... ,. ....... ...' ...... - ..... ............ ....

~ ~.,**1,**--~ ****~**JI *

  • I * . , . , .. . . . . Qlott.l* ") *****. * ,,, *t* . . . . 1*1,-, . ._,, .* , *** lfl'!.Sit .. ,.., .... ~.

0 ....*--.. _. ..,,,, ... , ..... """" ,,,v ..

  • -*~=-:- .~:-;. - .-ic:

~~~: .*::-, . " :' ~: . *-~...,==- =:~ .. ~ *~~.~ '-:t;:" ....... ;::!:':'.:- :0 ~: *: :'(11'::";"' ...... -:- ":"~-=- :::: r::.. r:

  • ...... - ~, 1 .. .. m.......... ,, ...... **-** r: ..... -.... ..,.: ., ... ,.. *--** .. ,, .... f..r ... *j,"':*** .... , ......... ***- *..** 1. . I'%

- R.:;;_:.!.:..:_::C: =:: L. ~::, .:_';#,'"".' j:!j'."~:~ :-;::.:* ~=-~~ :.:; *~ r: ~:. *::.:.: :~ ~~ ~.:..:£.:..~-t:;: I;~:; : : . : ~.:::: ~-~: :* l::; ~.,;r.:.::-;* ; ::':' =~~: r:

(JJ ...... ,.Ci> ***** 1* " ... '"fJt""* -*-**--.-- - .._.. *~* ...... *-** .......

. . . . . . . . ..,. ***- .-.. -- *r. -*-. '

""'1' *rr.***1"l"'. "<"" ......... ,.,., ....... ,_ . ,.... . . ~** ,...... ,,,~,*-**  ;*

1'" '" O 'C: - " ** ... *---*- *r.:* -+-* *:_o j ..... fft * " " *op* - ... ,.... -f L' * ' " * ., * . , ... ' I "" o, ** * * ,.,J, "**-* ..." ' ft*O** - ** .......

0 ***-**" fT1.. ***-***~

  • I ..'"' .." ..,... .......... ' . Q'. ................ ** *

~-*-*t .;.;..;. ~ ~** ..... ~ - * :.:'.:.. .a *** * * * : ... ~.*- ~.;..:.:* ~~*- .. ' .... ~!....:.: .:.~ .:.;.;.*  ! *, ~ )>.:.~~ J :_-::~~- :. ~ .::..:; .......~,v * -**~.:.. ~.";' .:::..!

"" ' ( "" I **" Ti'I '* " "~ ****d***-*oo ','-* ":i I:' .,,..,. **-* *~*~ ** ~* ** *.........~ +I""",.,,.,, ' 'r.::** * .... ,'.p**1 ""! * -!** - *

  • g_ :=:/~: L i~~i~*~:::: *~.-~ :-o.:~.!ii. 1::::: iE~ ~~m iili*L.r.a~.Iiii :111:.  :--~~t~m,~~*;:_ ~* ~-~~ *:::!.:'~.:~ *: 1 ... -1

- t~ifl:~ ~ ~ . ,. ..............

.µ,***Tt-~,.._. - ..~.....*:::::,........................ 1..................................................

....*. , . . . . . . . , :.. ** .*.. -: *..~**t**-.

    • o*** ...*****, *.3::r .... !-'fil:§'-****"._.. .. ,~ .. .,-.*I*~***." ......... .,.~,

a .... ,. . . . ... "'..t!!, .. ... --~* ---**-f<-*.1.. ..... , *-*** ...... -* .. **-*--**. u *-* ... , ""'""~***"' 1 ' ......... *-** -r.::*** ***--****"-"*--**

-=.
.t:...:n ..:~er... ~.:.. .:. .::._:..:.ni.:..:.::. ..... ~ ,_.,- . ,.,. . :.=.;.:..~~ ...... :: ;:.;..;..; :o ;.;:~ ,; o ** **to*.::.:. 1~:::Z-.:. 'i"""" .~;!,*~~.: .!..:::*...:..::.:;.

'"""j"l"'l"I .... .,* . . * * . . , ... --*-******* ***-P****** *******-*~*"*" ***. * - ..... ,. ... 0.;.:r: .... , .... "L!.' ,_,,.,,, .* , .**** **~" *'*******

.:~*:t:.**s *.* z** . . ::; .. **.: ..rw.-.:.;: :!=!.;.=*:..; :.:-::~ ::::~: :..:::***.~~-~:;: :1 ... ::::-~;..: .~::** *. ;-;*:~ :. ;*:.~~.! .;*~;;.:~.;.:- :*::-..::.-r::: :t";.t:*:*:'

N ["'""*.2 ..... r * * **O* ****-**** .. i .... * - - . . . . . , .. -*"* ***--* **** * - .... " . . . ...._ ... ,.... _ * ** ................. ' - * .... ; ...........1 0

' ** .. r *-*~*:*':'":" *--**

~.*-*'" =-~---*-*****

...... '"""'"0- 0"* ***'

    • -******-=*~-*[~"':"-.~**""" ... wo O *-t*'**-*'owo ***'"'"
  • -* *,:;:o *...... ...... ,""4,,., """*** ....... -~ ... - ........ - ........ -"""*"-"*

-0 ********"""'

..--~*:"':":"

......... - ...... ' ' ....... ::r ....... ...... ....~-*-*** *.................. , ......... '-*--.. . . . . . . -*-*'"""'""'"*--

.....,..,....._. *1 -**-***- . - *, *~;::.t *3--"*--~:::t.-~....... .. ~-- ---*. *-.. ,~:;T- .............. -.. h-*- -**** ..... - **N - ...... --*-.f. *- 'N*-r-- ..................

  • -, -*1- ......H.,r.*. o - **r* ....... - -_.,.1-....-:i.

),:~IJff~il ~;~~:-~  :: *{c::_;~~g;~  ::~TI-ff Si /'; nlh~~i *;:g~ ~~ ;~*iii_ .: J>.+r~~~t *~ ~r-;~ 'FFiH~~~ ~~~~. gff *~gfVi.:=f

! *-. .***. .. ..tD ........... _.. , *.* ~ ...... I .. _**~............. **-1 ..... ,. . -.t ... :e. ~-**.....................tt*z* ...:=: .*.

.:::..: .*. ~.:m. ~.-=1~:.::.~::-~ :r1r !"!_:* :.:--:  ::.;.~**: -:i.~:~  :~:~

~1 -;......... .. :~r~r=-=~:.~:.~": * ...... ::*.:::~:;:. :*..:t  :=.:; ..~.. :..~:.!-:-t:-=i::.

0 ....... ***-I**----.... ****** .......+.......... ****1*,~:_!__.::_ ---;*-' .,.,. ..... r, * ._.......... * ,, ** ," *****-** 1 ,., 1. ~ .. ; .* *'*" .,;., , *** , ..... ..

..;*1::!:

,..._,~,._...-

___ 0 _..._..,....., ,*..*. 0 ,, .....J....;..-*~* - - ...... ----***-

............ ... ,_.,l *~--- .. ...........__ ---.-...-- *-*rt**-***-**- ........_,_ ***-r , *****:t.****- ..... ...... -*--*- ..-- -*Z ...... *Z* ****-*** .............. ~..... -** .. . - -"*- **-**-*- ..... 1*****

=  ;.~;,~ ;.~;.* ~;~;. ;~ *;.;~"; ~;*;/;;* ;:;;:;*;~~;:

1 .. -***- ..............

~ LJ;_;*;~: ;~~;~;;;~ ;;*::1~~*;:.;~~;-~~~*; :E~ ;:~;~~ ~~~-~\.;;;~ ;~~~*~;~~ ~;;*; ;;~~; :.;;l'.;=;~ ~*;::":*:j;;;;

o .......... t.. ............... r-r:.1... -*~J-*" ... ;~..... .... :J .... , ...... 1.... ~. ............. *******-*-* ...... t .... ****::.r"**

. .~t~~:-~i *71*****!********** ~ ~;~:~f:1;.... ~~! r~ff-  ;~it~~~*; i~.#t'i"*'

,..... ,.................. 7ff ~:****~**" ~ ~~.ffi* -?i~[~i!"i ~f:t:t~j* ;:;;, ;~;i i~~ tt ~: ;;~ -~;;; f:f'~ Thi*~ *j ~:t~ ~*H.:-:: i:

          • .... .... J.**** .r1*:*ll ... _................ ***** '" ...... **:*;l*** :....[.....

,..:;..:~.:.~.:..:.:...:*...::'"*.:..;..:.!.:;.:* ~ l r ;.:.:,:.:..;~  :.:......:..:.,:(11  ::.;~  ;:!~

  • ..;..;.;..;..:..:.:.i, .~,:+:..:.!...:. :..~~ ..;,.,;.... * "' * * ** * ....... .:..::.:..:: - * * ~*:..:_, ~~.* .:.;.:.;..,~;,:..;.

............ ' ..... ,. ....... "" ...... 1-........ ..:r;,,, "'"J**r* ......................................... ,..... , ..... ,..... ;.*r** ..

  • 11.
.~:A*. riA*,~s..* t~T.~R ~ {s*r* :10. . Hir.t'c'. :: ~ :t.:; :;;7 E:~ :;;*: *::*~: ::.:-;* ~:*'.:. :*i:.: :~.;.; .!~~: ;;:~: !*! ;*: .::: i.'. ';.;_!i i~*:: ~!~;r:*::~
  • --- J\l: ..* ,,:, . I 1 , IL 4 f""\i ........ _.*"-**I- _ ... i...i.-.... *- *~*-~*--i ......... * .. ,._. - ..... _ _ _ .. .,*.*** -1.; ... -**-*\.. **'-~* * - t i ..... '!...... * - * *

. . . . **. ,;r........ r .................. *f. ..............J......,B** ...... I.. ...... , .......... ,............... ,~** . ,......... t ...

=~:~=f::i!:u~-:~~:.:~*~i;~l~*: 1:t:::::7~;::-r~:::*:1::~*;.:*~rI1:::~ ::-trt~:~: ::::~pp*:

.  :::-t  :~;.! n.::*~=~~ F:~~: ~~;: ~-;.~*:  :;-;r :f*;~d+T:~ t::rt;:*::

  • c 1'd ~lW e Ald a~J 6S:~1 175, L1... ~ntt

-.U-4-&..*1 ... 1...rol...1.-....... ;..., WW *

..... DC. .... u... ~ A..

D c

(j)

,.""1

"°......

.t>..

ro 0 2 4 6* 10 50 90 2l0 250 29(.

AUG 17 '94 rn:02 C&D PL"r' MTG P.3

  • .;::\.:.:::

.....":'.?.... ' r~:::r:.

      • :.;j:: ::l!;~;

'1 ' *..* , ..... ' .......:~: , * ..~:.:

    • r* *
  • ~ l**'~ ... ~  ;.!.:..! .!.!l~ .:.:.:.::. ~::...:~
  • r I'*.**- ... I .. ,
~-:::; *:. :;.!:.:::  ::~: ~t::!~* ~'H! H~~*

....L.JL

~~::-:-:t:-:-:*:

.. ~ .."f"';:*;;~*1**

I lot

.. ' _**Ill~ 1 I I

, ~....

I*** I "I~- IL~-~~

    • l*:j**-'

..1*-1 .I

: ~ ~
  • ~

o 1 1 1

: ~

_.j- I

.:.!*~*:

( 1

~

&l

,..... .. *-11****...

-*I***** ~ ____ -*

    • ,) *..--**o*

~

... o  ;;:~*:~-;.:.+~:::~::: ::.~:~o :~*.::::*:~~

~:-:-::/*ur~= .....,~.::* ~ * -* * * "."'.*:~*-=-*---*~*:

            • j"""""*****" 11.J ._...,...,,'

-~

.,,A****

........ ****!"- ............................. . -*****o

.... ~ ............... , . . . . . . . . . . . . . **I;:

  • ~

ci

.*-. ~ ~~{ i:;~~f~ ;~ ~-~ ~~~ t.Hs: ~ ~~1s~

~ '**1*** .... ~1-;-r* ............ 1.u. .*.** en

..,.***** ~"" i.*:.:*~.:  :.~::-:-'1:::-:=..u:  :: .:i:~ ~ :: ~ :- : :TI~r~

u "j ....

r .c ...~ ........

@¥l :;*: *nw9-* .. *-*- ~ ~ ~*** ... m' r ...... ****** .............. n::.

-.CD...

~-

~ ~1~}*i*.... Lz Wiii

.2.

~!

~ *I~*

!,J ; :::..::.- ;: -.: '**:.-; ,,

  • t ........ ..** J~;, ** ':f_ *

}:~:!~~*:* ::=-~~-- .~.!.:

-~M**

Q wll

rD **hl""* *--*

.. ..T.t~.a. **~ IJ:;~... .;:*~

gu~ *= ~; I **

~

r

~%

i;, l.l z-1.111!

IJ w

  • N-.D. .

... Cl*******

!!:' re 0 )f

~~

~

"1'l d

01ET2Lii:.N Cih'A/'~1 NO. ::l*lnA-;20 20 ){ 20 Pl:~ INC:H f'APl.H:

!i;Ula::o; Dlt:TZOEN co.

,,.,ADC t.N U... ~ J\.

.~--* ..

D cCf)

/ ...

'/ \fl

,µ ro

()

QO 0

'lJ r

-(

'lJ A

2 4 to 50 90 130 f70

PUG 17 '94 18: 06 C&D,_,,t='~ ~'.. J;'~G.- ..

ec-~-:i.~"' 1ri:l 1 ~= .......... .,....,

~

e Poat-It'" FP Nata IEEE BATTERY WORKING<

DATI:

bOMs TOI IOb . .Wl'I Del IWG llllllllcn Al we dflcwlRd b1 plaont 11rUer, I *m n1quOllln1 a rpot on the lepttmbu S'llMthal *pad& to dl1&11111 IM!l'll luuu related co lud~uld.ll1tterr tuMlll*RCG pr11tlcu, upeclaJJ7 pel11lnln1 io audear appllc1doa1. lmral 1ucl11r plant* art now eomplet1a1 their tru1Hlo1 to new ..,.IMI

.,.Clfltatlcm1(TI) baled on 1'H 1&1nd1rdlled TNJaaJcll lpecfftHtlOlil(S'i1) the IWG re¥fewed and tomm1nted on IMl'll )'lln qo, nJt actMC7 bu pnorated I lot of qucu.kHll oa ba~tel'f aumlllance *ethOcll *d pl'IC'dcea. WbUe wa m11 aot bl able tD addll'UI *JMClftc Tl llmla1,

  • dllcuulcaa ot tht buf1 tor .tetet11f11l*1 certal* llnaltl 111)' b1 verr helpftal. Dr'. liba of 1ht NRC b**

badlc1Md dl11t &omeDDI from ellt TS ,,... ot th* NllC m11 be 1bl1 Co Jola ut for Chi* dllcu11fon. Tbt tollowlac q111nlon1 Jn*1 be ultflll to *" the di.ICuaaton.

J, 'Whit r:nterla waurd be 1111d to d1termin1 th.t.t 1 battory 11 tuU1 cap*bll ot pertonnlq ltt f11tendeC1 tunctlanf Whit b1CCtr~/eeJllq110m 111nmoitr1 would bt ..,.ntlal 10 makln1 tilt*

cltiermhl*tlonf Dacri!M a pntral criterfa te* 1ettln1 the llmlta o* euh of dltN para11neten1' Would dlf1 N a pd ICNltfoa to l111450f

1. Wllat 11 tlal llult for . . "NIHl'*thumb" tll1t 1 IO*polnt(0,010) drop In 1ptelnc 11"1\11U Hl'l'tlpOlldl to.,~ NMtloa fft battol")' l!AplCltr(from UllSllO Jl:Ht 1o lohD Kno1)f Haw 11

'tltll nlatea to Tl 11... 1raramc11b that 1 value oto.011 b1Jaw th* mariufactunr'r fully cb1,...d IOftdlal apedftc 1r1vlt1 11 dl11'1ottrl1tlc ot 11 cbarpd cell ~Ith adequate CIJladt)'f If the

&"'IP 1pecSftc 1t1vltf of Ill C01Ut. .tcJ CCIII la found 10 be 20 pofntl bDIOW ~t f\lll~hl'pd 1

    • l11ll valut and *artier readfap bave bttn at tlle acmlnal 'Yllult wit.- amo111t* of
  • c1pacff1Ctecllntcau1 ltltMf-cbarp) IW bee1 IOlt' How 1* Chu detennlaedf C11t lt ~e lfatad that tbt b1het)' hM 111lftclt10 capadt1 to ptrfllrm "" laatendtd function ud maintain 1 dlltetft
    • rsla
3. II blftley ftoat charsln1 cur111u 1 ~*Id .method or deaerm1nrn1 Che 1e1te of c:harp GI a lead-add Jtauteyt t111 It bt 11ed In lleu cl 1ptelt1e trntt1 rw1dlnp1 WhJ It a 7..;a~ Uade&doa taarowtna
  • rwllarp afvtra tor lu HI tn *1&* ITSf Notti The attached 1C1chnJ1al piptr dfRllUll thlt

..a.tllln'*'L

4. WblC '&Jpn of Umlt1 lrt nqulrtl oa tncenell conntctlotl t11fltaneo1 tor maJnteuuc:1? ro..

perftrmlna llM lnttncled functlon(operabllltf)? Rr&w lhould cable ...,t11usc11 fa~lud1d la ldter-datlawplnck ""'*'ltu la .11aa111tttd tort 'Wauld the PM or a Umh fDr tMb 1¥p11 ut CGllMC'liml

... p MrllJ tohl Umle IN 1ccepllbleP Al *oted *~ 1 Ctr:Ulul paper en U01111ta1 tile 1t1tc er cba.._ at 1 le1d*1cf d b1i111"1 hllaS float cb1rsta1 cu..,. ta utache* for mttw and comm11U. Thia paper wfll b1 pn*ttd at INTILlt' N ID Novemller. I ua ukt111for1111 cram1111nt1 trttn the IWO m1111bl1a. In i:cmJunctlon wleb J, 1bcM, 1 ~o*ld like the IWG io ntmrm th Dll ao 1t1ttmfnU Jn aocdo* 4,1 amd Appendt1 .I coaomdn1 tM uN ol cbaralna cu mat. Wt ara 11tJ1orf111 aam* additional daf

  • on dal1 meibocl dla I hpe to bl¥t lt'IUQle at die metdq.

(I 1111 Mndlq tltll 10 Ill tbt .IWG mtmben &Ince )'DU ha\'C Alrerld1 ma!ltd th1 111oeel111 aotlce.l

f:;LJG 17 '94 18:07 CfxD PU MTG P.6 e

ASSESSMENT OF LEAD-ACID BATTERY STATE OF CHARGE BY MONITORING FLOAT CHARGING CURRENT Kyle D. f1oyd .. Souihem Company Semccs Inc.,

P.O. Box 2625, Birmingham, AL 3$202 USA Z. Noworollki

  • Pol)'uonics Engineorin1 Ltd. * .5200 Dixie Road Unit J8 Miaissagga, Onwio L4W 1E4 CANADA 1.M. Noworollld
  • Univmity of'Betkeley, Berkeley. Califomia USA
w. Sokolski
  • Ontario Hydro, Toronto, CANADA INTRQDUCTJO:i O'ICr &peeiflc gravity readings for usastns 1be swe ot cbarge oC a lead-acid battmy, Now the problem There are two methodl for 8llCliina the sune of tw2ll ~ the availability of COlt-etreetiw, acca1lte charge of a Jead-acld battery discuaed in the latest proviDOJll for mouuring tloat ewrenL The last pan IEEE std. 4.SO(J]. The most common method used in of thls paper presenu a test imuument dalsn the past baa been eloetrolyte spec!Ac gra~ty (S.O.) ~ally for taking .float c:urrent .readings.

measurement readiup taken with a hydrometer ftom ont: or more ceJls ot the 1-ttel')'. The other F!liLp DAIMVIRllNCJ SUMMAB}'.'.

method 10 determine the battery lta&c oI charp is the use of 1 ltabilized charging (ftoal) current maaurcd In 1988, one nue.lear pneratiq station blpn raJdns with a &aWtiw: elamp-on ammem or a Nit.able battery float cumm rcadinp &Ions with the roudae shunt and voltmeter. Seven.I cbangee within Ille specific gravity mdh1p. Shunts wore alnldy ba1U:ly user community have n°* made the me of imtalled in the circuits ~ that tho currem iDto or specific Jri\lil)' readfnp vory COltly hi aoam: cues out of the banay r:ould be mciuwed. A porllbll and impasaible in othc:n. For example, some users mi;rovoltmeter WU ullCl to take the readiftp. A&r have Nmed to automatic monitoring systems with c:ol\!Ulting the batwy manufa'7Nnrs in 1988, inlda1 remote ~rtin1 capabilities to zouanoly collccc ceil1ng values of 1 ampere and o.s ampere \tCl'C battery data. Then iJ only one known monitorin1 establishod for the lcpr IWicn baaeric1 am the syltcm that bu provisicns to meuwe specil\c *mailer dJesel ~erator battariea, rnpcc:Uvely. Tbae pavity. rt i1 still being tested and may not be cost current values were believed to live rmanable effCetive for many small battel)' iDlta.llations. In aauranee chat tho battlriea wore fully charged.

addition., some of thae lnsttllatiom have valve.

regula1cd lud"ICid (VRLA) batteries which have no Float wrnnt readmp were added to the weekly provil.ion tor measuring ~o lf2Mty. In fKt. the IUrwLllallee pl'CICOdura for 9 batteries coDlisUJ11 of I electrolyte iA itttmabillz.ed. making the 111cuurement total of 780 oelll. The overall wminai voltqe, :ftolt of IPCCific: gravity l~. With the lar1e c:urrent, and oomctcd IJ*iJIC gravity an nvmben ofVRLA blttcriel now in service and being summarized in the tibia below for batteries S lB, sold t.oclty, the 1111 or I.he flCll& ,,;umnt method of SlA. and D02A. Thil data is typical far the ot.bu asacain1 11111 ot charge i1 oxpected to h1crease. lderia. The nominal l*hour ampere.hour ntinp of the batteries were 2400, 1650, and 340 (410) for In 1918 ane user of flooded lead acid batteriea in a batteries SIB, S2A. and DG2A respcctMly.

~Jear plant began to measure bt current in S1tteriea SlB and S2A each have 120 '-kalciwn addition to S.O. readings. A COtaJ of 780 cells were cells with 1.21! nominal specific pvity electrolyte.

monitmcct. The reaultr of this experience are Batteiy D02A had 60 lcad-antimotty cdll, with summarized In lhia paper. A review of some of the 1.2U nominal sped.fie ll'lvity Wltil nlPlaced' with elcc:uochemisay involved it also J)l"aeDted. 410 ampere*bauf tead-calcium celli in April 1992.

The analysis of lhe collecuxi data has led to the eondwsion I.hat floa& cumnt monitoring is preferred 1

AUG 17 '94 18:08 C&D PLY MIG P.7 e

(.

u.n1ax 1;.1 DJ.Tl deftned in IEEE Std 4.~0(1), the battay is O"'"ridercd cbarpd wmn the float cwrent baa llabllWx:l (:DO BATr'UY FLOAT cou. lipli11c:an1 cbuap for J hours) at the f1olt valtaae.

VOLTAOB CURUN'I' IPEC. Thll WU roulinely *contitmed during each recbl1p (Volll) (Anl;ll) ORAY. after lold diacharp t~ cm may bstteria.

MIN'OO,JM 132.l 0.12 J.20!

M a wr/ at illusuatin1 the chaqing cycle, let'1 look AVEll.AOE IJ4.7 o.o 1..211 at a typical example. Typical data for the ncharp MAXJMUM 13$..C O.M l.2:17 tallawin1 a pedDrmaia tat for a llad-Qld11m blUCfy i1 shown in Fipre l.

STD.DEV. 0.61 0.14 0.00, I: 120 1.21 pmax 121 DA'l'A ~ 100 1.2 ~

.. eo Ic ea 1.1* I BA'mRY VOLTA.OE 1LOAT CURRENT c.-.>

CORK.

SPEC.

ORAV. ~ 20 40 1.11 i (Volll) 0.06 J.198* 0 1.1?'

MINIM\n.f IJ:Z.4 D 5 10 15 20 2S AV!.RACIE 134.-' 0.50 1.211 'TMNHJ\.N MAX1M'UM 140.0 2.:P *. 1.231 fl(BA.T.Ahf!G +SPEC. GRAV-AMP-lo-AN m::>.I>!V. Ulll 0.22 0.004 tOClii. BAT, AMflll * 'C!Oi 1oo.i AMfloH" IN* 1323 The hi1h initial ~t(>400A), limited oaly by the cumm Umit letting oithe eharger, flows for about 3 IUQBX PQ2A QAD haun. There l1 then a rapid drop in current fbllowocl by a transition into a slowly decaying current. Over BATTERY FLOAT CORR. 100% of the di&ebarge ampen-houn wen rcmmod VOLTAO! ctJllENT SPEC. within J houri. but it wu not until after 17 hcun (Volll) (Ampl) OJtAV, that tho charging Cmre11l ltabilized. Notice that the MINIMUM 130.0 0.01 l.20d apecifig sravUy rtldiDg ii only u 1.205 at 24 haun.

7 houn after the chargin1 current hu ltabllbled.

AVERAGE m.o us l.219 nm i* still 10 point1 below the narma1, fllll-charp MAXEMUM t3U 1 0.41 l.234 lpleiftc gravity ot 1.215.

STD.DEV. l.29 O.OI 0.006 From tho example lboYe, ii should be clear that Ndt: n. nlu. muU4 wilh UI Ul.i.k (') Ui . . to IN charlins cummt rapondl more quickly than iplCi&

...... a.& ¥0ha91,... wMi die~ pity readinp io changes in the S111e-of<hlrae CIJlll WIN npllcil4 .ttJa i..n.-Jcilllll C.111 1n April and provides 1 better illdicatioa ol a tOturn to full 1992.

cbar1e.

V1vm1 1.1ruy me ***nap1nar \1VOISCI)' pilot-cell readinp.

~ uo1Cm1uans may oe maa.e 1r0m an analysis of the detailed data 81 well .. th* statistical data a muoh better lllCllmCDt of mu: oC charp c:an be tabulated above. The detail data shows 'very liltle made with tloat current than with specific jp'l'Vhy.

correlation betweea the spec:ifig gravity llllclinga and These ob.orvationa are also supported by the blttely

  • tbc llClUal state at Cbarte at a given point in time. JJ syllem opaaticin m"iew given below.

2 .

AUG 17 '94 18=09 C&D PLY MTG e e P.8 A tew by paint.a ooiaming battery l)'ltem Lead dioxide~) and sponge lead (Pb) an &be operation are ~ here. Ill tlolt open.lion, ac:tiw matmala isl ~ positive and neptiVl!I ~

tbe hlttmy, charpr, and IOlds ue collMCted in ~ly. Thi ~ acid CH2804) ii die paralld. The cbarpr normally nppliu the loads elCU'0!)1cs and the llld sa1fltt and W8sar UV and the float cwnnt iDtO Ulo battery. lf dle cblrpr prodw:ls of tho dilcbarp ~D. The cUcblrp output ii lolt '1t madequate to IUPPlY die lOlds, the rwtioa. gae1 ftom left t.o riaht and the chl'l'p batael)' immediacely mppliu the requinld eurrena. mcdoD from risbt to Id. Both the platel amt the Nonual hcl1le IO&dl OD the di-1 gcam1U)r and elecUalyta ue inwlvm ill iu rmaion. Leid IUl&te lllltion bltterim are ilL Iha rap ot 10 to 100 ii fonned Ii botb tbe petid.je and ne,.UV. plMel amperes. :rapectiwly. Tbacfore, on a kla of charger during cUICblrp and thl nli\iric add ii cxmvertld in Olltpu&. the bluery Q1ITCm immediately changes theprocm.

di1'Wcm Ind inmeuet dJ'amldcally, al lcut by I lac:tor ot 1o. 'Ibil &harp current wowd continue M noted above. durinl a d!lcbarp, the SUlturic ICld until the chlrpr omput ii l"ClltOred or tbe batteries ii belq oonverted to lea4 sulfate ad MW It tbl are ftalJy dllicJwaed. If the battery bas beef! plates. Thi weaker acid ft'om the pl1111 dJmJlll imo dilCharaed and then placc:d on chlqc, the battay the bulk electrotyte, decreuin1 the spocifk; gravity.

currem will inidally ilaeuc in the charging While cbarpng, the lead IUllate ii canvertecl blCk to difectioa and remain 1tp.iftcantly hiper(ampa VI plate 8'.1h'I materilll and sullWic acid. It is milliamp) tJwl normal until the chirp* hu been important to keep in mind that thl1 reaction is returmld. The rwlative mapitudo and dlrection of the o=urrlng in the active nweriab of the plates, not in battcry(f1oat) current itt conjundicm with the battery the blllk electrolyte. AJ the add within the plala mminal voltage pmvidel a timely, accurate bec:Ome11 more demc. it leaves the plates and diffucs il2dtcadon of swe-af-charp. VflfY slowly through the ileetrolyte nilln1 tho specitie grayity ot the bulk elocuol)'te to the tull*

Ono 1111 obieMtion concemina the n0&1 i:umnt c:barp level. Alf'/ currenl hi ex=- al that requited data should be made. The ceillilg value far float to convert tb1 .vailable lead IUlf'aUI pa lam tbl current muse be selected. to allow ror \he variadon1 electrol)'si11 of water ill the elo:troJ)'te, t!ml reta*n1 oxpected during Mtmal opention. Since lhe float hydroaen at the nepavc plates and DXYJell ai tbe currem readin1 will lncreue dram*dwly for a positive plates. It 11 thil paiq ICtlon that helpl to partiall)t dilcharpd battery, some MhiOll aboYe the mix the elecirolyte. Since both discblrp and cbarle nonna1 "raled 11 float CWTC'N ii polliblo ud even reactiom involve cUmWon ot the electrolyte, the desirable. 11te statlltical dita *howl that the avenge Rate of cbarp indicated b)' apeciftc pavity readlnp flOll current plus 2.5 lltandard deviations was under inberattly Lap the actual state of charge of tho cell.

the ceilina value on all the bacteria. The detailed especially durins charge. In a lead-calcium cell.

data trom battay S2A tam dmins the panial -which pua much 1eN than a lcad"8l\lirnoDy cell, uhlrp also ahowa that cvcn f'or putial dilldw9e1, tho mi"'1\g ot the electn:ilyte ii much mare Ule float cwmrt hlcrMlies dramaUc:ally to correctJy dependent on cUtl\Won. and tho lag in lpll:iftc:

alert the um ta pcllliblc probleml. gtl\'ity readinp i1 inore .,ronounced.

ILECTBOCQMJCM BIACJ'IONSJll\'llW Thi open circuit voltage of a cell is d.lrectly nlat&ld

[2,3,4) ta the specific ,mity of the eleeuolyte and maN specifically to lhe acid ~tration in the ~

A review of some ~ of tbe charge and .nwcrial* or the plate&. In a abilizod cell, where che ditcbal'ge nac:tiom of a lead.acid battery may prove electrolyte ls homcpncioua, the &pec:l& pavitJ ot helpful hctc. The daublHUJAtc rheory ii now the bulk elc:ctrolyte la the 1&n10 u that near tho commonly aCCCl*d 10 delc:ribe the buic chenW;aI pla1n. The open circuit volrap of a fully dmpd 1*tiona oc:c:umn1 witbln. a lead-acid cell during cell with a nominal 5J*iftc gmity of l.21S ii cbmge and discharge. The chlmK:IJ equation below approximately 2.06 volts. Tho voltage of a mmrflllM the overall suctions ot this theory. discharged cell will ba lower. Al soon u charging starts. tu1lUric acid ls formed in the plates and the Pb02 +Pb+H2So4 =2PbS04 +2H20 (1) cell voltag~ rises, opposing 1he applied cbarpq voltage. ConceptUall)'. this pJOQC:Sa can be explaintld by eqwalion (2) below.

J II

P.9 AUG 17 '94 rn: 10 C&D PL'r MTG e

E-Eb rcleubt1 sues through electrolysis Of water.

l=-- (2) rAMOUlly, the ftnt c:ompcmmr. is the rwt impol\llll R and, ~tel)', It ii the prot'enntial chemical rm.ctkln u MD. Tiie leCODd eompcment only limU after the cell voltap bu rillD *"" the open cUcuit

\11.luc. Tho tu& component 11 not desirlble. but DY cmrent in excm cf U1at needed for t.be Int two ClOlllponcn&I ii WIOcl Jn thil way.

While equatiOn (2) smn ~ ii holpftll to The applied wltap *!II fl held CDDAUl by the viM11ze what ii blppeniq mthe cell. it does little chargor. The cell w.ltage ~b" i1 dependent on the to quamlf1 tbe rmaJca 1e111 ill the voltqe and curiat concentration of lead ioal. dMJent ud tetmalent, durin1 cl'llqiq. apeeJ&Uy during float opntioa.

awillble tor reac:daa. Thill nladmlihip is exprmed Flcat operadoD is more cloar:IY delCribod uiq Tafel in tbl followinJ equadon. whic.b hU been derived Una u dllcribtd ~.

hm the Nemst' equatiott. See reference [$] or anocher elecuochemistry text fbr the derivation.

  • On .floet cbarp. the wrreni ftawin1 thtculh a lear.l*

add cell and the applied voJtqe arc rcJatcd by iu (Pb++++) Tafel charlcteristics. A typical Tafel Iii. graph is p; 111 1.87 + 0.0291og 2 (3) &l\own in Fipro 2.

(Pb++)

The quantities enclosed in parentheles are the number of lead ions available for BKtlon and are small !n number. The 80Urc:e ot the ~ena ions (Pb~ I I I ) ,, the small amount ot tho lwl dioxide that i1 lcaized. The only source of divalent Jons i1 lead auJAte which ii produced duriq diacharp u

~ above. Tbe uncunt ol llld IUlfatc within the cell will be at 1 nwdmwn when the cell i1 fuily clischatsed and at a minimum whea 1\J.Uy charged.

Therc:rore. tar a Allly d!lcharpcl cell the c:oll vcltaSC will be It I minimum Whan ftn& COnmctod to the cbarar. The int=nal czll l'Mimtn'! 1 wry low value md doesn't cbanp putly whether the c*l is ftllly charpd or di.tcharpd, but it wm be bipr in a fully dilclwgod cell. llcferriq &o equation (2) abow. Jt can bl teen that the current will be 11 a awdmum 'llDdel' theae conditiona tor a given dulflin1 volt.Ip The dhc:barpd coll continue. to cbarse at or near the maximum c:urrent available Each cell type will gcnetally have its own spocit1c flOm the charger until the awilahle lead mllatc is paph. These snpbi have several line* 1howins tbe almost cxhauted. At this paint. &he reduction in the relationship of the (;Cil voltqe to the :float cwmat, supply at divalent* iom causes the cell voJtase to lllUally givm in mJcroampaes per ampere-hour~ a..

incfoue to I value appioaching that of the charger. hour ?ldng, The poaiti'.\19 and nepdve plate When au tho nailable lead sulfate bu been polarization voltap1 1te a110 lhown. but miy be converted. the cell i1 ftlUy dwpd and the only ipored tor our p.uposes. Knowing the applied etimnt ftowin1 i1 that required to overcome the cbarsin1 voltage and the cell nominal l'llinl in self-dilcharp l'CICdOlll at U. plates and any &mpere*houn, one call determine the expecled flalt electroJysj1 of Wltn caUICd by lhc applied vo1ta11e. current for a liven cell type. The actual tmralled The cbargi.fti emrcnt can be made up of thn:c value of flaa1 cutrent varies with temperature and componenu uai in (l)rccharpng the Cf.11 by .

ap. AJIO some allowance must be made f'or i convertin9 lcad sulf&te, (l)oY~rcoming solt-di1ehar1e manut'ac.turing tolerances between cells. A portion -:Jf by .main1a.lntng proper plate potentials, and (3) 4

P.10 RUG 17 '94 18:11 C&D PLY MTG e

this data ii confitmod routinely aAer the batte.des an withlWld the maximum battery c:um:nt wi1baul wembled into .vibp prior to the uory c:apagity damlp.

ta Only the .float current aad cell voltqea are

  • IYlillble, but UU. ia all thaC is needed for our The ib.unt and portable \>Oltmeter melhod may not be puipo5e1. tJlin1 data obtained ftom the ppha prac:lical or CY'lll P*fulc far many applicatiom.

and/or ftctoiy teCCl'dl, c:eili.ng vaJua of Allboulh Hall Eff'ect meterl will witbitaDd biP floac(ehaqinl) cumm can be developed for eurrents, a=urtte SMllW'ellkats below a few mrvoill&nce purpcllei. The battery wndor can help in unpora are dil!ku.11 to obtain.

IO!ectiq these values.

In addition ro Hall E&ct amsora, therCI me meUIOdll Blled on the expericitce with the W10 of both of nMUing tho core of a current traufonner ml methCJdl of dewminiq the ltat9 of cb.rge of I meuuring the llCODdary current immediately after a battery, we have dltennimd that the cbargi111 rnei pulM [6,8). Si=e, illitially WI core will bo

  • current method oft'en 1m1ral ldvanlapl over the fully rc:sec. die woNtary current 111 dirsrly ptOpOr*

apecific gravity method. Socne ot the advantaaa are tional to the primary current Md <:111 be mil)'

lilltd below.

  • muswed. With the pwap of time the =e wW be driven into saturation and wUl lose its tiaa.stbnNsr
l. Cbaraina ~ is a more meaninlfui lndic:ator MuactoMict. 1be l1IRI pu1ac ii applied apin Ind than speciAc gn.vity since wmnt is the primary the procc11 ii repeeitecl. By utag thil md.bod means ol delivering power into and out of the measurement ol OC current can be easily obtained.

bitter)'. Howcm, the misc oC IUCh a "DC cunent transformer" is limited by the reset current puJtc

2. Chargin1 eutreft1 responda more quickly to amplitude and 10ilQ in the COf1, The appllcatioll of eha.nps In state-of-<:harge, In fact, lhc carefuJ large cumnts lO the primary of such a uanaformer aclection of a ceilin1 current value Is very will not destroy IOmicanduaor dMcu on lbe important to allow for normal variations. MC:Ondary.
3. CharsiJlg cummt mote cloMly rcfl~ the The physical OOle 11izc to be llsed for float current condition ot the whole battery than the specitic measurements ruun be abJe to accept laqe gravjly ot a pilot cell. conduc:t0n Cllt)'ing full dilcharge cmrent. Hence the core will be of !dgniftwit dimensions. Since core In conciumon, m ~ of determining the state loua dc&ennine the lower end al current Rftlin11 of chars- cf a lcad<<id battery have been ~bed drcuiuy, It is dimcult to obtain reliable raultl Uling in llOme detail. One method ot readinc charging a *oc* current trudo.rmer when the primuy curnnt bu been explained. while me rcmJts of current Is lower than a few tena of millla.mpma.

aevcra1 )'W'S of uing both methods has been presented. Bued oa tho experie.acc piaed with the clwJins c:uncnt m=dlod, the secluW:al background measured current and the general trend 'Within the bauery indusiry, we r.comtncnd the use of dw'sins cumm to determine the .i.ate of charge of 1 llld<<id battery. While It i!

true tl1at not iaany baUcry l)'lteml were initially Conlrol dllipcl with provi1ions for n:adinl charging FipreJ current. there are othor meuurement teehniqua that W0\1Jd allow t.ho retro.fit of those systems. The operatioo of one such technique t1 dOllCribed below. Figu.re 3 shows the device, ope~tin1 on the prindplc of a 18.lurable reac:ror <lteillator, which addreuu JNSTBYMENT OPIMTJON some of these limitations. The measured current puses through the cenler of the ferrite com. The The float cumnt in a fully cbarpd battery ia in the winding of the ferrite itself is cannocted to &be QDJ'e milliamperes ran1e tor the more common sizes used SET circuitry.

in stadonary applicatiom. Insttuments used to monitor this curtent ml.lit be capable of accurately meuming thit small cummt and also be able to .

s

P.11 AUG 17 '94 18= 1i C&D PLY MTG e e 0

  • The magnetization flux magnitude in the ferrite core oa ts. Some of the paruitic contributm which we ii the sum of flux pncatecl by die meuund current haw identi11ed are.:

aa.d the nux of the SET windiDS on the ferrite.

  • resistance of the winding and the cumnt loop Conaider a cue where the meuwed current is equal ued to SET the cote to zero. A voltap VL* is applied acroaa the SET
  • raidua1 mpaic :Seid ln the con windin1 ot tho con. The cunent will atart to rise
  • external mlpWC field with tile speed given by the followmg equation.
  • ncill ia the meuared conductor
  • tmllpenlUn f!_Kt_ (4) Topther. these pm.sidcl sipUlcantly deteriorate di L our &tsnal-to-JIOilo rado (SNR). P:igun 4 preeenll 1 VL* Volrap ...._I<< wW!1ne technique to roducD the intluenee of many of tbe above P1P115itie1.

L*~fl1ht8"~

~Ol.lrTn The masnr:tie flux in the core will start to 'rise and after a cenain amount of time, ti, will reach the satumion point. --ill~liii!P-vI :;--2-~---::~ I 4..zA~'l.r(B0 - B )xl08 18 .. ---.::o...-~-- 1

(-') 81:1' ~

v Figun 4 wt.I; ti* tllllll required 1o ~ ~ A known DC vclcage ii applied to the SET windhlp A* C.. ....- Gl'U. oan( amA) by a MOSFET switch. with an Internal resilllnCC N .. lllllllM o£1111m V* lpplled valiaet whieh is very low compared to Ulc total rnillance of Bo, Bl* IDi&W-' ..wr.umaavx dmlity (O.J the SET wimli111. OllQO tho fCIU.ltin1 wrrw rca;bcs a referc:ncc value, the MOSPET is named ojf.

allowing the ferrite core lO raet. NtltJr a At this point. uic c:umnt will im:rme rapidly, an predetermined Ume (which is not critic:al far tNe1U which can be e.ullv detected bv the loa:ic's m*m1P1P.mfl!ltt*)i. *It~ Ml'\~m:l'T i* tn....M - . 1110-:..,

circuitry. and the process ia RIU&ed.

Note that lhl time to rr.ach sanuation (ts) is a A mlcrcproc:essor mwuR1 the ON time of thl function of lhe initial fillX density. Natura.II)', thi1 MOSFET and calwlates an avenge of many implies a IWnple depondeme on semed CC current. meuW11ments. An average ON time is ltmd by a With a comtant voltap applied to the set winding, rnieroproc:eAOr. Nm, the curnm direcdon Jn the lhc time required to reach 1 llturation point will SET core i1 revened and the pro=u la repeated.

depend OD. ma&Ntude and direction ot the sensed DC cum:nL For example, it the flux produced by the lbe meuunns. averasin1 and storing procm is sensed current bas the same di!Wdion as the flll'I: repcatod apln. Finally, the diffC11nce between the ptOducecl by the SET winding, ts will be shortened. two l\'CJlied reac!inp 11 c:alcwattd. This "differential" result ii proportional to the current ot all anaJos vllvee; time i1 the one which oan be nowm, throu1h the 1CNO wire. Nate t.tw chis meuured the molt accurately. With proper sizing af di11'erentiaJ techniquo areatly reduces the dfeeU of a sensins transformer we CUI obtain quamizod ts changes in temperature. voltage and ~. The values for 1 wide~ rango. only unbalanced influence is the extcma1 mqnetic quasi-suuioiwy field (e9. earth'* maptic field),

A particular problem of this delign is the influence Tht tldudion of thia error soun:e j1 poAlible by ot GUier paramoten on ts, In puti~lar, when placing additional ferrite cores on each side of the attemptJng to mwuR ~ small currents, extcmal JDQsuring COl'C! and COl'lductinJ oft'set meuurmnents influences ean have a c:omparativc:ly lar1e influence during initial installation. Of course. in most 6

-~

AUG 17 '94 1s:12 C&D PLY MTG P.12 e

iu**tn*iom Chcl error c:oatribudon from ~ Large 1-d Storage b&Ucries for Generatins magnaic 8elcb ii ne&lisihle. Fillllly, high frequency Stadom and Subltatlou. IEEE Std. 4$0. 1987 WI low frequency noise. comribu&iou are paily dec'eued by use or multiple avenpd umple1. {l) CJ. W. Vinal, Storap Batterl~I, Fourth Edition. New York. John Wiley A Som.

It i1 iateltltiq ta noie that when the meuurement 19.SS.

cmreut is iDCl'lllMd owr cerilin ~ whidi gm be ciemcted by tJw: mechDd delcribed, WI)' tmail (3]  !. A. Hoxie. ..Some Cbargiq Cbanaeristic:I modilc:ation will permit dcllaioa of a large currcnt of Leid-Add Batteries", A.I.!.!. Conference f2owiq through the lallll eote. (Pig. !) Paper #'6*1036.

(~) H. B. Haring and U. B. 'l'bamU.

Electrocbemicll Behavior or Lmtd. Leid*

Alldmaayt lad Lcld-Ca1dum Cella",

Tramacdol1I ot the Electmchemical Soeiety, Vol. 61, l 935.

[$1 H. I. Crei&htoa. Prlncipl11 and App/lcotlon1 Now the circuit will work on 1 cWfemu principle:. of El,ctroclr~lfti81ry, Vol I. Founh Edition, The coro will be reset only in the dJrection oppo1ite New York. John Wiley, &:. Sons. 19S l to tM mwured ;urmi&. and immediately after resetting, the voltage acrou the burden raisior will [6] ll Severns, w1mprovin1 and Simplifying HF be meuured. The limple 11111ple and hold amplifier DC Currmit Semcml". Confem.co Pro=iedinp will measure tho cmrcnt during the time of the 1986 IEEE Applied Power Blectronic:I immediately precediJ1I tho reset pulse, Iii dacribed Confereaco (APSC '16), pp. 180*183, Now 1.n111. OrlCllDI, Lcuisisn1 1 April/May l 986 Furthermore it ii a11a worth cbicrvins th.al the SET (71 c. Swlondcr, *Mapctic Current Sensors for pulle praent on the soxmd*ry at the mcuuring care Spam S&alion Pnicdom*, Confema will, ia fact, bVoct a much Jarpr cumnt into the Proceedfnp of the 1991 IEEB Applied Power battecy DC clrcuit It the froquttU:y and current of BlcQtronica Confennt:e (APEC '91), pp. 635-tbJ1 SET pullC: ii ommollcd ud volta10 .641, Dalla, Texas.

meuu.rement1 acnm indMdual c:ell1 or the battery are sampled with synchronous frequency, it is [8] A. Radum and J, Rulison. 11 An Alternative poaible tc use suc:h c:ircu.Ury not only to measure low-cou c:umnt*RDlinl &eheme for hi~

float and charge cumnt 1Nt also intemal impedance current power dcctronics circuiu*,

ot individual celll when thl battary is on float Conferm Proceedinp of the 1990 IEEE lrulmtry Appllcadorui Society Annual The PCJlyU'Onics Eqineerina. BTMJOOOP battery Meetins, pp. 619-625, Seattle, Wu!Unston.

momtoring illltnll'llCnt baaed OD the abcM prillQple October 1990 is being used u 11 permanently hutalled. monitorin1 1)'111111 on stationary and UPS blttcric.. Thi.a l)'ttem {9) T. Sonoda and R. Ueda, "A Current Snor or perm.ha the oblervati.on 1 lmA float c:umnt change High ~ l.ftd Hish Seuitivtty't, on the 500 MCM condUCIOI' cable in the presence of Conference Proceedinp ot the 1990 IEEE the hip ripple AC c:utftftt normally present on UPS Industry Applicttiom Society ADpnal battery inmllatiom. Mcctini. pp. 626-631, Seattle, Wuhingten, October l !190 BERUNC'E§:

(101 w. A. Geyser, 11Dl11pOZidve Mqnetice (1) !EBB R.ccommended PractiOD for Neliniue". Editura tehnic:a. BbCUl'elli, 1968 Maimenance. Testing, and Replacement of 7

,\

Retrieved from "https://kanterella.com/w/index.php?title=ML18101A228&oldid=2505574"