1-4 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
KBD
CM
AD
T
N
T
++=
-
www . ElectricalPartManuals . com