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.
Expensive.Also,thereareconstraintsonprocessingandmountingtocontactsprings.
Likesilver,iteasilydevelopsasulfidefilminasulfideatmosphere.However,
acertaindegreeofcontactstabilitycanbeobtainedevenwhenswitchingloads.Careis
requiredatlowvoltageandlowcurrentlevels.Furthermore,contactresistanceisrelativelyhighandresistanceto
corrosionispoor.Adisadvantageisiteasilydevelopsasulfidefilminasulfideatmosphere.
Ag
(silver)
Electricalconductivityandthermalconductivityarethehighestofallmetals.Specialcharacteristicsare
uniformthicknessandthenonexistenceofpinholes.
Auplating
(goldplating)
SimilareffecttoAuclad. Contact Protection
• Counter EMF
W itc tiv ith a
D irc its ,
D C
s rta to
a ith to
p .).
3.
AgPd
(silver-palladium)
Atstandardtemperature,goodcorrosionresistanceandgoodsulfidationresistance.Dependingontheplatingprocessused,supervisionisimportantasthereisthe
possibilityofpinholesandcracks.Excellentarcresistance.
However,highcontactpressureisrequired. Characteristics Common Contact Materials
C ris tic ria re
g n
s tin y.
• 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 .
Auflashplating
(goldthin-filmplating)
0.Goldcladisusedtopreventpolymerbuildup.
AgSnO2
(silver-tin)
ExhibitssuperiorweldingresistancecharacteristicsequalorbetterthanAgCdO.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
ds_x61_en_relay_technical_information_091112D 621
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TechnicalInfo.
Contact
Material AgW
(silver-tungsten)
Hardnessandmeltingpointarehigh,arcresistanceisexcellent,anditishighlyresistanttomaterialtransfer.
G lly ritic tric
b lta rd
te t
2 lts r
e e
c i2)
s il.Exhibitslowcontactresistance,is
inexpensiveandwidelyused.
• 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 ).Therefore,itisusedinhermeticsealed
relays(reedrelays,etc.Greatlyeffectiveespeciallyforlowlevelloadsunderrelatively
adverseatmospheres.
W tiv itc d
off, to
s lts h
ca d
g tly rte life.Inan
organicgasatmosphere,careisrequiredaspolymersmaydevelop. f
p lin d
re .5pm
Purposeistoprotectthecontactbasemetalduringstorageoftheswitchordevicewithbuilt-inswitch.
AgNi
(silver-nickel) Equalstheelectricalconductivityofsilver.
Rhplating
(rhodium)
Combinesperfectcorrosionresistanceandhardness.Oftendifficulttoimplementcladcontactsinexistingrelaysduetodesignandinstallation.General Application Guidelines
lim ite tiv a
b f
re rily f
c rre ity C
c irc its .
2. rre e
lo tiv r
less, ill e
ig itio e
d tte r
c k
d its on
th t
fa ilu .
Surface
Finish
Auclad
(goldclad)
Auwithitsexcellentcorrosionresistanceispressureweldedontoabasemetal.
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.
.Asplatedcontacts,usedforrelativelylightloads.1to0.).Relativelyeasytoimplementgoldplatinginexistingrelays.
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. is
d ira so
th less.Expensive
