Technical Data
10-12 7SJ62 Manual
C53000-G1140-C121-1
10.3 Inverse-Time Overcurrent Protection (51 and 51N Elements)
Pickup and Time
Multiplier Ranges/
Resolutions
Pickup Current 51, 51N 0.50 A to 20.00 A
1
) (Increments 0.05 A)
1
)
Time Multipliers for T
p
, T
Ep
0.05 s to 3.20 s (Increments 0.01 s)
I
p
, I
Ep,
IEC–Characteristics or ∞ (delay does not expire)
Time Multiplier for 51, 51N D 0.05 s to 15.00 s (Increments 0.01 s)
ANSI characteristics or ∞ (delay does not expire)
Trip Time Charac-
teristics As Per IEC
As per IEC 60255-3, Section 3.5.2 or BS 142 (See also Figure 10-1)
The trip times for I/I
p
≥ 20 are identical to those for I/I
p
= 20.
Pickup threshold approx. 1.10 · I
p
Dropout threshold approx. 1.05 · I
p
for I
p
/I
N
≥ 0.3
Tolerances Pickup Currents I
p
, I
Ep
2 % of setting value, or 50 mA
1
)
Trip Time for 2 ≤ I/I
p
≤ 20 5 % of reference (calculated) value + 2 %
current tolerance, respectively 30 ms
Influencing Vari-
ables for Pickup
Power supply direct voltage in range
0.8 ≤ V
PS
/ V
PS nominal
≤ 1.15 1 %
Temperature in range
23º F ≤ ϑ
amb
≤ 131º F 0.06% /10º F
Frequency in range
0.95 ≤ f/f
N
≤ 1.05 1 %
Harmonic currents
– Up to 10 % 3. Harmonic 1 %
– Up to 10 % 5. Harmonic 1 %
1
) For I
N
= 1 A, divide all limits and increments by 5.
t
0.14
II
p
⁄()
0.02
1
–
----------------------------------
T
p
⋅
=
1250$/,19(56( (Type A)
t
13.5
II
p
⁄()
1
1
–
---------------------------
T
p
⋅
=
9(5<,19(5(6( (Type B)
t
80
II
p
⁄()
2
1
–
---------------------------
T
p
⋅
=
(;75(0(/<,19 (Type C)
t
120
II
p
⁄()
1
1
–
---------------------------
T
p
⋅
=
/21*,19(56((Type B)
For All Characteristics
t trip time in seconds
T
p
setting value of the time multiplier
I fault current
I
p
setting value of the pickup current
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