1-2
BE1-50/51B-229 General Information
9252000892 Rev A
APPLICATION
The BE1-50/51B-229 has a wide range of pickup settings and front panel selectable time characteristics.
This makes the relay compatible with applications involving coordination with fuses, reclosers, cold-load
pickup, motor starting, and fixed time requirements. Two switch-selectable reset functions are provided:
instantaneous and integrating. The instantaneous reset function avoids ratcheting. The integrating reset
function simulates the disk reset characteristic of electromechanical relays.
SPECIFICATIONS
BE1-50/51B-229 electrical and physical specifications are listed in the following paragraphs.
Current Sensing Input
Nominal Rating:
5 Aac
Continuous Rating:
14 Aac
One-Second Rating:
400 Aac
Time Overcurrent (51) Element
Setting the TIME PICKUP control at the minimum pickup setting places the relay in the most sensitive
state and may be used as a safety setting.
Pickup
Setting Range:
0.5 to 15.9 Aac
Setting Increment:
0.1 Aac
Accuracy:
±
2%,
±
25 mAac at or above 0.5 Aac setting
Dropout
Dropout occurs at 95% of pickup value.
Timing Range
0.0 to 9.9 seconds in 0.1 second steps.
Timing Accuracy
The timing accuracy is the sum of
±
1 cycle,
±
2 percent over the range of 1.3 to 40 times tap. This
accuracy is for a given measured multiple of tap. The measurement of the multiple of tap has an accuracy
that is the sum of
±
2 percent,
±
25 milliamperes.
Timing Accuracy Example
Pickup Setting:
5 Aac
Current Applied:
6.5 Aac
+Multiple Tolerance:
6.655 Aac
−
Multiple Tolerance:
6.345 Aac
Time Curve:
E
Time Dial:
5.0
Minimum Time (6.655 Aac):
46.5470 sec
Maximum Time (6.345 Aac):
61.3968 sec
Curve Time (6.5 Aac):
53.1800 sec
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.
K
BD
C
M
AD
T
N
T
+
+
=
-
Summary of Contents for BE1-50/51B-229
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