1-2
BE1-50/51B-237/-238 General Information
9252000899 Rev —
Internal switches provide for selecting system-operating frequencies of 50 or 60 Hz, instantaneous
element delays of 0.0 or 0.1 second, characteristic curve group selection for either GE IAC or ABB type
curves, and instantaneous or integrating reset characteristics. Switch location and description is provided
in Section 2.
SPECIFICATIONS
BE1-50/51B-237 and BE1-50/51B-238 electrical and physical specifications are listed in the following
paragraphs.
Time Overcurrent (51) Element
BE1-50/51B-237 Pickup
Setting Range:
0.5 to 15.9 Aac
Setting Increment:
0.1 Aac
Accuracy: Sum
of
±
2% and
±
25 mAac
BE1-50/51B-238 Pickup
Setting Range:
0.1 to 3.18 Aac
Setting Increment:
0.02 Aac
Accuracy: Sum
of
±
2% and
±
5 mAac
Dropout
Dropout occurs at 95% of pickup value.
Characteristic Curves
Available curve types follow IEEE Standard C37.112 (1996) and emulate standard GE IAC, ABB CO, and
BS142 curves. Appendix A,
Characteristic Curves
illustrates the available curves and lists the applicable
constants.
Curve Types:
Short Inverse, Long Inverse, Definite Time, Moderately Inverse, Inverse,
Very Inverse, Extremely Inverse, BS142 Very Inverse, BS142 Extremely
Inverse, Fixed Time
Time Multiplier:
11 curves for each characteristic
Timing Accuracy:
±
1 cycle,
±
2%. This accuracy applies to the range of 1.3 to 40 times tap
and is for a given measured multiple of tap.
Fixed Timing
Setting Range:
0.1 to 9.9 s
Setting Increment:
0.1 s
Timing Accuracy:
±
1 cycle,
±
2% of the time to trip for time dial settings
≥
0.1.
Reset
Integrating:
Simulates the disk reset of electromechanical relays and begins when
the current decreases below 95% of pickup. Appendix A,
Characteristic
Curves
illustrates the integrating reset characteristic curve and equation.
Instantaneous:
Reset occurs within 16 ms of when the current decreases below 95% of
the pickup level.
Instantaneous Overcurrent A (50-A) Element
BE1-50/51B-237 Pickup
Setting Range:
2 to 99 Aac
Setting increment:
1 Aac
Accuracy: Sum
of
±
2% and
±
25 mAac
BE1-50/51B-238 Pickup
Setting Range:
0.4 to 19.8 Aac
Setting increment:
0.2 Aac
Accuracy: Sum
of
±
2% and
±
5 mAac
Dropout
Dropout occurs at 95% of pickup value.
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