GEK-49848A
RESET
OV ERCURRENT UN IT)
I nvers e time overcu rrent units reset a t 90 percent of the m1n1mum picku p
c urrent, very in ve rse time u nits at 80 percent and extremel y in ve rse time units at
85 percent.
When the rel ay is de - energized, the time required for the disk to compl etel y
res et to the n umbe r 1 0 time dial position is a p pro ximatel y six seconds fo r inve rse
time rel ays and 60 s econds for bo th very inve rse- time and extremel y inverse- time
rel ays.
OPERAT ING T I ME
The time cu rve for the directiona l unit is s hown in Fig. 12.
The time c urves of the TOC u nits a re s hown in Figs. 1 3, 1 4 and 1 5,
res pectivel y, for inve rs e- time, very inve rse- time and extremel y invers e- time rel ays .
For the s ame o pera ting conditions, the rel ay wil l o perate re peatedl y wit hin one o r
two per cent o f the s ame time.
The time cu rves for the dire ctional l y control l ed I O C units a re s hown in Fig.
1 6.
The time- current cha rac teristic o f the H i-Seismic non-directional l y control l ed
IOC u nit is s hown by Fig. 1 7 a n d its 'tra n sient o verreach ch ara cte ris tic is s hown by
Fig. 1 8.
BURDENS
The po tential circuit bu rden o f the directional unit at 60 cycl es and rated
vol ts is ten vol t- amperes at 0. 8 9 power fa ctor. Tabl e 8 gives the c urrent circ uit
burden o f the direc tional unit. Tabl e 9 gives the to tal bu rden o f the TOC unit pl us
the directional l y control l ed u nit.
Tabl e 10 gives the burden of the n o n
directional l y control l ed I OC unit.
I MP ED.
( OHMS )
0. 46
TABLE 8
D I RE CTI ONAL UNI T CU RRENT CI R CU IT
B URDENS AT 60 CYCLES AND 5 AMP ERES
V OLT-
POWE R
AMP ERES
FACTOR
12. 0
0. 52
9
WATTS
6.24
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