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