Basler Electric BE1-50/51B-233 - Manual (Page 14)

Integrating reset characteristics are defined by the following equation and shown in Figure 1-1. Equation
constants are provided in Tables 1-2 or 1-3.
Integrating Reset Equation:
1 M

RD
T
2
R

Where:
T
R
= Time to reset in seconds
R = Constant for the particular curve
D = TIME DIAL setting
M = Current in multiples of PICKUP setting during reset
1.0
10.0
100.0
0.000 0.200 0.400 0.600 0.800 1.000 1.200
Multiple of Pickup
x
R
D (Second
s
)
P0
04
6-
11
Vertical axis xRD (Seconds) is applicable for all curves and is derived from
multiplying the constant R for the curve selected times D (the Time Dial setting).
Figure 1-1. Integrating Reset Characteristic Curve
Instantaneous Overcurrent (50) Element
Setting the INST PICKUP control to the minimum pickup setting places the relay in the most sensitive
state and may be used as a safety setting.
Pickup
Setting Range: 1 to 99 Aac
Setting Increment: 1 Aac
Accuracy: ±2%, ±25 milliamperes at or above 1.0 ampere setting
Dropout
Dropout occurs at 95% of pickup value.
Curve Characteristics
Instantaneous characteristic curves are similar to standard electromechanical instantaneous units.
However, the time to trip for applications where the initial current through the relay is less than 0.4
ampere may be slightly longer. This may occur on a very lightly loaded circuit or when the relay is
providing ground protection and is connected to measure neutral current. Figure 1-2 shows the
instantaneous characteristic curves for maximum time to trip.
An additional fixed delay of 0.1, 0.2, or 0.3 second may be added with internal switches SW3-1 and
SW3-2. This delay applies to both phase and ground applications. Closing switch SW3-1 provides an
additional delay of 0.2 second. Closing switch SW3-2 provides an additional delay of 0.1 second. Closing
1-4 BE1-50/51B-233 General Information 9252000897 Rev B