T
rip units .......................................................................................................
Electronic trip unit (Micrologic)
A-16
7ULS XQLW WKDW FRQWLQXRXVO\ PHDVXUHV WKH FXUUHQW ÀRZLQJ WKURXJK HDFK SKDVH DQG WKH
QHXWUDO LI LW H[LVWV )RU 0LFURORJLF WKH PHDVXUHPHQWV DUH SURYLGHG E\ EXLOW LQ FXUUHQW
VHQVRUV OLQNHG WR DQ DQDORJ GLJLWDO FRQYHUWHU ZLWK D KLJK VDPSOLQJ IUHTXHQF\ 7KH
PHDVXUHPHQW YDOXHV DUH FRQWLQXRXVO\ FRPSDUHG E\ WKH $6,& WR WKH SURWHFWLRQ
VHWWLQJV ,I D VHWWLQJ LV RYHUUXQ D 0LWRS UHOHDVH WULSV WKH FLUFXLW EUHDNHU RSHUDWLQJ
PHFKDQLVP
7KLV W\SH RI WULS XQLW RIIHUV PXFK EHWWHU SLFN XS DQG GHOD\ VHWWLQJ DFFXUDF\ WKDQ
WKHUPDO PDJQHWLF WULS XQLWV ,W DOVR SURYLGHV D ZLGHU UDQJH RI SURWHFWLRQ IXQFWLRQV
Magnetic release
A-14
5HOHDVH DFWXDWHG E\ D FRLO RU D OHYHU $PDMRU LQFUHDVH LQ WKH FXUUHQW H J D VKRUW
FLUFXLW SURGXFHV LQ WKH FRLO RU WKH OHYHU D FKDQJH LQ WKH PDJQHWLF ¿HOG WKDW PRYHV D
FRUH 7KLV WULSV WKH FLUFXLW EUHDNHU RSHUDWLQJ PHFKDQLVP $FWLRQ LV LQVWDQWDQHRXV
7KH SLFN XS VHWWLQJ PD\ EH DGMXVWDEOH
5HÀH[ WULSSLQJ
A-8
&RPSDFW 16; FLUFXLW EUHDNHUV KDYH D SDWHQWHG UHÀH[ WULSSLQJ V\VWHP EDVHG RQ WKH
HQHUJ\ RI WKH DUF DQG WKDW LV LQGHSHQGHQW RI WKH RWKHU SURWHFWLRQ IXQFWLRQV ,W
RSHUDWHV H[WUHPHO\ IDVW EHIRUH WKH RWKHU SURWHFWLRQ IXQFWLRQV ,W LV DQ DGGLWLRQDO
VDIHW\ IXQFWLRQ WKDW RSHUDWHV EHIRUH WKH RWKHUV LQ WKH HYHQW RI D YHU\ KLJK VKRUW
FLUFXLW
Release
,(&
'HYLFH PHFKDQLFDOO\ FRQQHFWHG WR D PHFKDQLFDO VZLWFKLQJ GHYLFH H J D FLUFXLW
EUHDNHU ZKLFK UHOHDVHV WKH KROGLQJ PHDQV DQG SHUPLWV WKH RSHQLQJ RU WKH FORVLQJ
RI WKH VZLWFKLQJ GHYLFH )RU FLUFXLW EUHDNHUV UHOHDVHV DUH RIWHQ LQWHJUDWHG LQ D WULS
XQLW
Shunt release (MX)
A-83
7KLV W\SH RI UHOHDVH RSHUDWHV ZKHQ VXSSOLHG ZLWK FXUUHQW 7KH 0; UHOHDVH SURYRNHV
FLUFXLW EUHDNHU RSHQLQJ ZKHQ LW UHFHLYHV D SXOVH W\SH RU PDLQWDLQHG FRPPDQG
Thermal-magnetic trip unit
A-14
7ULS XQLW FRPELQLQJ WKHUPDO SURWHFWLRQ IRU RYHUORDGV DQG PDJQHWLF SURWHFWLRQ
Thermal release
A-14
5HOHDVH LQ ZKLFK D ELPHWDO VWULS LV KHDWHG E\ WKH -RXOH HIIHFW $ERYH D WHPSHUDWXUH
ULVH WKUHVKROG WKDW LV D IXQFWLRQ RI WKH FXUUHQW DQG LWV GXUDWLRQ ,
2
W FXUYH FRQVWDQW
ZKLFK LV UHSUHVHQWDWLYH RI WHPSHUDWXUH ULVH LQ FDEOHV WKH ELPHWDO VWULS EHQGV DQG
UHOHDVHV WKH FLUFXLW EUHDNHU RSHQLQJ PHFKDQLVP 7KH SLFN XS VHWWLQJ PD\ EH
DGMXVWDEOH
Undervoltage release (MN)
A-83
7KLV W\SH RI UHOHDVH RSHUDWHV ZKHQ WKH VXSSO\ YROWDJH GURSV EHORZ WKH VHW PLQLPXP
Compact NSX
Glossary
G-12
( LQGG
YHUVLRQ




