1-6
BE1-50/51M General Information
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the instantaneous reset timer to zero when timed dropout occurs. This fast reset characteristic prevents
the ratcheting effect that may occur with repeating system faults. Closing SW3-4 selects the integrating
reset characteristic. The integrating reset characteristic simulates the disk reset of electromechanical
relays. When the integrating reset characteristic is selected on 100 series relays, insure that sufficient
input power is available to power up the relay. This is not required on Series 200 relays. Series 200 relays
provide the integrating reset function even when input current falls to zero.
Integrating reset characteristics are defined by the following equation and shown in Figure 1-3. Equation
constants are provided in Tables 1-3 or 1-4.
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 1-3. Integrating Reset Characteristic Curve
Instantaneous Overcurrent (50) Element
Setting the INST PICKUP to the minimum pickup (0.2 on the 1 ampere unit and 1.0 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:
0.2 to 19.8 Aac
Setting Increment:
0.2 Aac
Accuracy:
±2%,
±5
milliamperes at or above 0.2 ampere setting
5 Ampere Unit Pickup
Setting Range:
1 to 99 Aac
Setting Increment:
1 Aac
Accuracy:
±2%, ±25 milliamperes at or above 1.0 ampere setting
Summary of Contents for BE1-50M
Page 1: ...INSTRUCTION MANUAL FOR OVERCURRENT RELAY BE1 50 51M Publication 9252000990 Revision N 03 08 ...
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