Ashida ADR141A - Page 60

ADR141A /
ADR241A
Doc ID : ADR241A_IM_01
Ref ID : ADR241A/IM/PLF
Rev No. : 02
Page No. : 60 of 150
For IEC Inverse Curve
t =
K* a
I
I ref
b
–
1
For Extremely Inverse C4A Curve as per EE relays
t =
K* a
I
Iref
b
– 1
* 1.3
+ 0.22
Where
t = operation time
a = constant
I = Input current
Iref = Current threshold setting
b = Constant
K = Time multiplier setting
Curve Type Description a b
C1 Normal Inverse_1 0.14 0.02
C2 Normal Inverse_2 0.06 0.02
C3 Very Inverse 13.5 1
C4 Extremely inverse 80 2
C4A
Extremely Inverse
(C4A) as per EE Relays
80 2.2
C5 Long Time Inverse 120 1
C6 Define Time - -