Multi-Function Control ETMFC610
http://www.entecene.co.kr
225
EN
HANCED
TEC
HNOLOGY
8.2.9. User Curve - Time Overcurrent Curves
The ETMFC610 has a total of 62 kinds of standard curves: ANSI / IEEE curves, IEC curves, US
curves and Definite time curves, KEPCO ES curves, KERI curves, 4 user-defined curves, 3 fuse
curves, 32 nonstandard curves. According to Standard ANSI / IEEE C37.112 and IEC 255-3, trip
operation times and reset times can be defined as follows.
The operation times and reset times are defined as follows :
US
Trip Time(Sec) = TD
×
(
α
/ (M
β
-
1)
+
γ
) + TA
ANSI/IEEE
Trip Time(Sec) = TD
×
(
α
/ (M
β
-
1)
+
γ
) + TA
IEC
Trip Time(Sec) = TD
×
(
α
/ (M
β
-
1)) + TA
ES
Trip Time(Sec) = TD
×
(
α
/ (M
β
-
1)
+
γ
) + TA
USER-DEFINED
Trip Time(Sec) = TD
×
(
α
/ (M
β
-
1)
+
γ
) + TA
RESET TIME
Reset Time(Sec) = TD
×
(Rt / (1
-
M
2
))
Table 8-3. Curve Factor
TD
Time dial
TA
Time adder
α
,
β
,
γ
Characteristic constant
M
Multiples of pickup current
Rt
Reset characteristic constant
NOTE :
“CB clearing time curves”
are used when rated voltage of CB is 15
㎸
or 27
㎸
, otherwise
which added 30
㎳
(
±
4
㎳
) are used when it is 38
㎸
.
