
Multi-Function Control ETMFC610
http://www.entecene.co.kr
230
EN
HANCED
TEC
HNOLOGY
8.2.9.4. Fuse Curves
1) RI Curve Trip Time
“RI” curve is a special curve to be used in conjunction with mechanical relay. When “RI” curve is
applied,
time overcurrent
element is operated by following formula.
Is
I
Time
Trip
236
.
0
339
.
0
1
Here,
TD
is set time dial,
Is
is pickup current for time overcurrent element.
I
is actual fault current.
2) HR Curve Trip Time
“HR” curve is a special curve to be used in conjunction with the fuse. When “HR” curve is
applied,
time overcurrent
element is operated by following formula.
1
.
0
1
10
66
.
3
)
832
.
3
(
2
log
Is
I
Time
Trip
Here,
TD
is set time dial,
Is
is pickup current for time overcurrent element.
I
is actual fault current.