Panasonic is part of a large worldwide groupselling relays and associated switching products under different brand names in different territories.The conditions of use in some territories may differ from those customary in Europe. In particular there are often major differences in regard to national and international specifications, such as UL, CSA, VDE, SEV, EVE, SEMKO, etc. Thus, when considering contact loads as stated in this catalogue (e.g. 10 A, 30 VDC for the SP relay) its hould be understood that these values are not necessarily an absolute maximum but tested ratings. Mostly the stated value has been tested for a certain life expectancy as stated by the manufacturer or the respective test house. Thus, under different conditions, the stated “maximum” may, in practice, be safely exceeded.
f
p lin d
re .Dependingontheplatingprocessused,supervisionisimportantasthereisthe
possibilityofpinholesandcracks.Expensive.Expensive.Goldcladisusedtopreventpolymerbuildup.
W tiv itc d
off, to
s lts h
ca d
g tly rte life.
However,highcontactpressureisrequired. Contact Protection
• Counter EMF
W itc tiv ith a
D irc its ,
D C
s rta to
a ith to
p .Furthermore,contactresistanceisrelativelyhighandresistanceto
corrosionispoor.
Contact
Material AgW
(silver-tungsten)
Hardnessandmeltingpointarehigh,arcresistanceisexcellent,anditishighlyresistanttomaterialtransfer. Characteristics Common Contact Materials
C ris tic ria re
g n
s tin y. is
d ira so
th less.Asplatedcontacts,usedforrelativelylightloads.).
Ag
(silver)
Electricalconductivityandthermalconductivityarethehighestofallmetals.
Surface
Finish
Auclad
(goldclad)
Auwithitsexcellentcorrosionresistanceispressureweldedontoabasemetal.However,indrycircuits,
organicgasesadhereanditeasilydevelopsapolymer.
C tio irc its t
m ria ria tra r
s d
as lly a
c tio e
c tio rs
on itiv s
(s f
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TechnicalInfo.
2.General Application Guidelines
lim ite tiv a
b f
re rily f
c rre ity C
c irc its .
Rhplating
(rhodium)
Combinesperfectcorrosionresistanceandhardness.However,
acertaindegreeofcontactstabilitycanbeobtainedevenwhenswitchingloads. rre e
lo tiv r
less, ill e
ig itio e
d tte r
c k
d its on
th t
fa ilu .5pm
Purposeistoprotectthecontactbasemetalduringstorageoftheswitchordevicewithbuilt-inswitch.
.Relativelyeasytoimplementgoldplatinginexistingrelays.
Auflashplating
(goldthin-filmplating)
0.
Peak voltage
meter
^ Several hundred
to several
thousand volts
(a) (b)
Figure Example counter emf and actual
measurement
In i/
d ith d
a ith rity in
F tiv e
lo itc off.Greatlyeffectiveespeciallyforlowlevelloadsunderrelatively
adverseatmospheres.
Auplating
(goldplating)
SimilareffecttoAuclad.Careis
requiredatlowvoltageandlowcurrentlevels.Specialcharacteristicsare
uniformthicknessandthenonexistenceofpinholes.1to0.Adisadvantageisiteasilydevelopsasulfidefilminasulfideatmosphere.).
AgPd
(silver-palladium)
Atstandardtemperature,goodcorrosionresistanceandgoodsulfidationresistance.
AgNi
(silver-nickel) Equalstheelectricalconductivityofsilver.
• Material transfer phenomenon
M ria tra n
o lts ils t
m ria tra s
th itc tio s
in rfa s
d re
1 fte ile ts
lo is
o fte irc its re
p ts
“ rre is
la tiv itiv s
o rre e
(s f
a ).
AgSnO2
(silver-tin)
ExhibitssuperiorweldingresistancecharacteristicsequalorbetterthanAgCdO.
3.Exhibitslowcontactresistance,is
inexpensiveandwidelyused.
M lic in
th ly
p lim t
th itc t
g lia ility
o itc g
fre itio in
th ire e
a ith
A d
c tro r
th ire (fo
m ire lic tio tc.Inan
organicgasatmosphere,careisrequiredaspolymersmaydevelop.Also,thereareconstraintsonprocessingandmountingtocontactsprings.
G lly ritic tric
b lta rd
te t
2 lts r
e e
c i2)
s il.Oftendifficulttoimplementcladcontactsinexistingrelaysduetodesignandinstallation.Therefore,itisusedinhermeticsealed
relays(reedrelays,etc.
Likesilver,iteasilydevelopsasulfidefilminasulfideatmosphere.
• Current
T rre d
o tim irc rts
im rta flu n
th ith e
e rre tim f
c irc it, ,
a tra r
in d
c tra tio n
im .Excellentarcresistance
