Basler Electric BE1-50/51B-231 - Manual (Page 14)

1-4 BE1-50/51B-231 General Information 9252000895 Rev C
† Figure numbers refer to the characteristic curves located in Appendix A, Time Characteristic Curves.
‡ Curves B and C are defined in British Standard BS142 and IEC Standard IEC 255-4.
§ Fixed time delay, adjustable from 0.1 to 9.9 seconds.
Reset begins when the current drops below 95% of pickup. Integrating reset simulates the disk reset of
electromechanical relays. BE1-50/51B-231 relays provide the integrating reset function even when input
current falls to zero.
Integrating Reset
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
Figure 1-1. Integrating Reset Characteristic Curve
Instantaneous Overcurrent (50) Element
Setting the INST PICKUP control at the minimum pickup setting places the relay in the most sensitive
state and may be used as a safety setting.
Setting Range ............................ 1 to 99 Aac
Pickup
Setting Increment ....................... 1 Aac
Accuracy .................................... ±2%, ±25 milliamperes at or above 1.0 ampere setting
Dropout occurs at 95% of pickup value.
Dropout
1.0
10.0
100.0
0.000 0.200 0.400 0.600 0.800 1.000 1.200
Multiple of Pickup
xR
D
(S
ec
on
ds
)
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).