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BE1-50/51B General Information
9252000991 Rev N
SPECIFICATIONS
BE1-50/51B electrical and physical specifications are listed in the following paragraphs.
Current Sensing Input
1 Ampere Unit
Continuous Current:
2.8 Aac
One Second Rating:
80 Aac
5 Ampere Unit
Continuous Current:
14 Aac
One Second Rating:
400 Aac
Time Overcurrent (51) Element
Setting the TIME PICKUP control at the minimum pickup setting (0.1 on the 1 ampere unit and 0.5 on the
5 ampere unit), places the relay in the most sensitive state and may be used as a safety setting.
1 Ampere Unit Pickup
Setting Range:
0.1 to 3.18 Aac
Setting Increment:
0.02 Aac
Accuracy:
±2%,
±5
milliamperes at or above 0.1 ampere setting
5 Ampere Unit Pickup
Setting Range:
0.5 to 15.9 Aac
Setting Increment:
0.1 Aac
Accuracy:
±2%, ±25 milliamperes at or above 0.5 ampere 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%. This accuracy applies to the range of 1.3 to 40 times tap
and is for a given measured multiple of tap. The measurement of the multiple of tap has an accuracy that
is the sum of ±2%, ±25 milliamperes for 5 ampere units, and
±
2%,
±
5 milliamperes for 1 ampere units.
Timing Accuracy Example (5 Ampere Unit)
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
K
BD
C
M
AD
T
N
T
+
+
=
-
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