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.
EachoftheothercontactsreturnstoN.020inch
gapismaintained.Forcedoperationmethod
(2FormA2FormB,
4FormA4FormBtypes)
Evenwhenonecontactisweldedclosed,theother
maintainsagapofgreaterthan0.5mm.Theoperation
ofeachcontactisregulatedbythemovementoftheothercontact. Thismakesitpossibletodesign
variouskindsofcontrol circuitsandsafetycircuits.
Inthediagramontheleft, thelowercontact “b”have
weldedbuttheuppercontact “a”maintainatagapof
greaterthan0. contactshaswelded,theotherthreecontactshave
returnedowingtothede-energizingofthecoil.SF4D
SAFETY STRUCTURE RELAYS
T t
s d
c e
w g
a s
( r
d ,
a l
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s e
s ,
f e
a d
r f
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582 61407 sf4d: 180413D
.
Inindependentchambers,thecontacts“a”and“b”arekeptapart byabody/
caseseparatororbythecarditself.020inch.O.
Structure Operation
1. Independent operationmethod
(4FormA4FormBtype)
Enablesdesignofsafetycircuitsthat allowweld
detectionandreturnat anearlystage.5mm. Eventhoughone
oftheexternal N.
4.O.020inch. 2FormA2FormBcontact
4FormA4FormBcontact
Structurewithindependent COMcontact of2FormA2FormBand
4FormA4FormBcontacts.5mm. contactwelds, a0.O.
Noneoffourcontactsareheldinpositionbythearmature.
Subsequentcontact movementissuspendedandthe
weldcanbedetected
Thetwocontacts“a”and“b”arecoupledwiththesamecard.
Asshownatthetoprightofthediagramontheleft,if
theexternal N.
3.
Independent COMenablesdifferingpolecircuit
configurations.
2.
Asshownonthediagramontheleft,evenifthe
operatingspringsnumbered 1and2thereisno
shortingbetween“a”and“b”contacts. because
thecoil isnolongerenergized. Separatechambermethod
(2FormA2FormB,
4FormA4FormBtypes)
Preventsshortingandfusingofspringsandspring
failureowingtoshort-circuit current
