9252000981 Rev G
BE1-50/51B-219/-226 General Information
1-3
Timing Accuracy Example (BE1-50/51B-219)
PU
setting:
5
amperes
Current Applied:
6.5 amperes
+ Multiple Tolerance:
6.655 amperes
– Multiple Tolerance:
6.345 amperes
Time
Curve:
E
Time
Dial:
5.0
Minimum time dial
using 6.655 amperes:
46.5470 seconds
Maximum time dial
using 6.345 amperes:
61.3968 seconds
Curve time using 6.5 amperes: 53.1800 seconds
Curve Characteristics
Nine inverse time functions and one fixed time function can be selected by the front-panel Curve switch.
Characteristic curves for the inverse and definite time functions are defined by the following equation.
Where: T
T
=
time to trip in seconds
D =
time dial setting
M =
multiple of pickup setting
A, B, C, N, K =
constants for the particular curve
Time characteristic curve constants are listed in Tables 1-2 and 1-3. Constants have been selected to
conform to the characteristics of electromechanical relays over a range of pickup multiples from 1.3 to 40.
Values of the constants are provided for use in computer relay setting software. Timing accuracy is
±
1
cycle,
±
2 percent of time to trip.
Table 1-2. Time Characteristic Curve Constants with SW3-3 Open (Off)
Curve Type
∗
Constants
BE1 Similar
To
Figure
Number
†
A B C N K R
S ABB
CO-2
A-1 0.2663
0.03393
1.000
1.2969
0.028
0.500
L ABB
CO-5
A-2 5.6143
2.18592 1.000 1.000 0.028 15.750
D ABB
CO-6
A-3 0.4797
0.21359 1.000 1.5625 0.028 0.875
M ABB
CO-7
A-4
0.3022
0.12840
1.000
0.5000
0.028
1.750
I ABB
CO-8 A-5 8.9341
0.17966
1.000
2.0938
0.028
9.000
V ABB
CO-9
A-6 5.4678
0.10814
1.000
2.0469
0.028
5.500
E ABB
CO-11
A-7
7.7624
0.02758
1.000
2.0938
0.028
7.750
B BS142-B
‡
A-8
1.4638
0.00000
1.000
1.0469
0.028
3.250
C BS142-C
‡
A-9
8.2506
0.00000 1.000 2.0469 0.028 8.000
F None
§
N/A 0.0000
1.00000
0.000
0.0000
0.000
1.000
K
BD
C
M
AD
T
N
T
+
+
=
-
Summary of Contents for BE1-50/51B-219
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