Schweitzer Engineering Laboratories SEL-501-2 - Page 77

Date Code 20010518 Testing 6-3
SEL-501-2 (MB2/MB4) Instruction Manual
7DUJHW ; < ,167 $ % & 4 1
/DEHO
. . . . . . . .
,QGLFDWHV 33 43 13 33  43 13 
6WHS &RQQHFWDVLQJOHFXUUHQWVRXUFHWRRQHSKDVHFXUUHQWLQSXWRI5HOD\;
6WHS 7XUQRQWKHFXUUHQWWHVWVRXUFHDQGVORZO\LQFUHDVHWKHPDJQLWXGHRIFXUUHQWDSSOLHG
XQWLOWKH33HOHPHQWDVVHUWVFDXVLQJWKH$33/('WRLOOXPLQDWH1RWHWKH
PDJQLWXGHRIWKHFXUUHQWDSSOLHG,WVKRXOGHTXDOWKH33VHWWLQJ
Residual Time-Overcurrent Element: 51NT
1RWH 7KHVWHSVWDNHQLQWKHH[DPSOHWHVWIRUWKH17UHVLGXDOWLPHRYHUFXUUHQWHOHPHQW
RSHUDWLQJWLPHPD\EHDSSOLHGWRWHVWWKHIHHGHUUHOD\37DQG47WLPHRYHUFXUUHQW
HOHPHQWV5HOD\;LVVKRZQLQWKLVH[DPSOH
6WHS ([HFXWHWKH6+2:FRPPDQGDQGYHULI\WKHUHOD\VHWWLQJVIRUWKHUHVLGXDOWLPH
RYHUFXUUHQWHOHPHQW6HWWLQJVRILQWHUHVWDUH131&17'DQG156
6WHS 8VLQJWKH6(7;FRPPDQGVHW33+4313331+DQG43WR
2II7KH2IIVHWWLQJGLVDEOHVWKHVHHOHPHQWVOHDYLQJRQO\WKH17HOHPHQWHQDEOHGWR
WULS&RQQHFW;287WRDQH[WHUQDOWLPHU&RQILJXUHWKHWLPHUWRVWDUWRQDSSOLFDWLRQ
RIFXUUHQWDQGVWRSRQRSHUDWLRQRIWKH;287FRQWDFW
6WHS &RQQHFWDVLQJOHFXUUHQWVRXUFHWRRQHSKDVHFXUUHQWLQSXWRI5HOD\;
6WHS &DOFXODWHWKHH[SHFWHGRSHUDWLQJWLPHWSRIWKHHOHPHQW8VHWKHHOHPHQWVHWWLQJVDQG
WKHRSHUDWLQJWLPHHTXDWLRQVVKRZQLQWKH7LPH2YHUFXUUHQW(OHPHQW2SHUDWH5HVHW
&XUYH(TXDWLRQVVXEVHFWLRQLQ6HFWLRQ2YHUFXUUHQW3URWHFWLRQ7'LVWKHWLPHGLDO
VHWWLQJ17'DQG0LVWKHDSSOLHGPXOWLSOHRISLFNXSFXUUHQW
)RUH[DPSOHLI13 $1& 8DQG17' ZHFDQXVHWKHHTXDWLRQ
EHORZWRFDOFXODWHWKHH[SHFWHGRSHUDWLQJWLPHIRU0 DSSOLHGFXUUHQWHTXDOV
0,13 $
Ü
Ý
Û
Ì
Í
Ë
¼ 

0

7' WS


WS VHFRQGV
6WHS 6HWWKHFXUUHQWVRXUFHWRGHOLYHU0,13DPSVDQGWXUQWKHFXUUHQWVRXUFHRQ7KH
WLPHUVKRXOGVWDUW:KHQWKHWLPHRYHUFXUUHQWHOHPHQWWLPHVRXW5HOD\;VKRXOGWULS
VWRSSLQJWKHWLPHU7KHWLPHUHFRUGHGVKRXOGEHDSSUR[LPDWHO\HTXDOWRWKHWLPH\RX
FDOFXODWHGLQ6WHS
1RWH ,IWKHWLPHRYHUFXUUHQWHOHPHQWLQGXFWLRQGLVNUHVHWHPXODWLRQLVHQDEOHG156
356RU456 <WKHHOHPHQWXQGHUWHVWPD\WDNHVRPHWLPHWRUHVHWIXOO\,I
WKHHOHPHQWLVQRWIXOO\UHVHWZKHQ\RXUXQDVHFRQGWHVWWKHWLPHWRWULSZLOOEHORZHU
WKDQH[SHFWHG7RUHVHWDQHOHPHQWEHIRUHUXQQLQJDGGLWLRQDOWHVWVHQWHUWKH5(6(7
FRPPDQGIURPWKHUHOD\VHULDOSRUWRUWKH(/FRPPDQGXQGHUWKH0$,17
SXVKEXWWRQIURPWKHUHOD\IURQWSDQHO