Basler Electric BE1-50/51B-121 - Manual (Page 17)

9252000994 Rev P BE1-50/51B-214/-215/-223/-225 General Information 1-5
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.
BE1-50/51B-214/-215/-223 Pickup
Setting Range ............................ 1 to 99 Aac
Setting Increment....................... 1 Aac
Accuracy .................................... ±2%, ±25 milliamperes at or above 1.0 ampere setting
BE1-50/51B-225 Pickup
Setting Range ............................ 0.2 to 19.8 Aac
Setting Increment....................... 0.2 Aac
Accuracy .................................... ±2%, ±2 milliamperes at or above 0.2 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 (5 ampere relay) or 0.08 ampere (1 ampere relay) 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 second may be added with internal switch SW3-2. This delay applies to
both phase and ground applications. Closing switch SW3-2 provides an additional delay of 0.1 second.
Section 2 illustrates the location of SW3.
The instantaneous element in BE1-50/51B-214/-215/-223/-225 relays may be set lower than the
instantaneous element in IAC relays and still have the same reach. This is because the BE1-50/51B-214/-
215/-223/-225 instantaneous element effectively eliminates the fault current transient overreach
components. When calculating BE1-50/51B-214/-215/-223/-225 relay instantaneous element settings,
calculate the symmetrical value without any adder for transient overreach.
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).