Eaton Digitrip 3000 series - Digitrip 3000 Curve Equations

DT3000 Instruction Leaflet
I.B. 17555D Effective: Date 07/02 Page 61
For more information visit: www.cutler-hammer.eaton.com
Supersedes I.B. 17555C dated November 1999
7-2 DIGITRIP 3000 CURVE EQUATIONS
Thermal Curve Equation
SLOPE M
IT 1
I
2
T2
I
4
T4
T = Trip Time
D = Time Multiplier (0.2 to 40) IT 1
I = Input Current I2T 2
M = Slope (0 = FLAT, 1 = IT, 2 = I2T, 4 = 14T) I4T 4
K = 3 for phase, 1 for ground FLAT 0
FLAT 0
ANSI/IEC Curve Equation
Where:
I = Input Current
I
pu
= Pickup Current Setting
D = Time Multiplier Setting
P A B
ANSI MOD Moderately Inverse 0.02 0.0515 0.114
ANSI VERY Very Inverse 2 19.61 0.491
ANSI XTRM Extremely Inverse 2 28.0 0.1217
D = 0.1 - 5.0
step of 0.1
IEC-A Normal Inverse 0.02 0.14 0
IEC-B Very Inverse 1 13.5 0
IEC-C Extremely Inverse 2 80 0
IEC-D Definite Time 0 4
D = 0.05 to 1.0
step of 0.05
I
M
I
n
T =
D * K
M
I
P
I
pu
T = D *
-1
+B
A