Section 3: Supervision Functions; Cb Fail (50Bf) - Siemens 7SR224 Technical Manual

Section 3: Supervision Functions

3.1

CB Fail (50BF)

Figure 3-1 CB Fail
Voltage Inputs:
Current Inputs:
Disable:
Map Pickup LED:
The circuit breaker fail protection time delays are initiated either from:
A binary output mapped as Trip Contact in the OUTPUT CONFIG>BINARY OUTPUT CONFIG menu,
or
A binary input mapped as 50BF Ext Trip in the INPUT CONFIG>INPUT MATRIX menu.
Apply a trip condition by injection of current to cause operation of a suitable protection element. Allow current to
continue after the trip at a level of 110% of the 50BF Setting current level on any phase. Measure the time for
operation of operation of 50BF-1 Delay and 50BF-2 Delay. Repeat the sequence with current at 90% of the 50BF
Setting current level after the element trip and check for no CB Fail operation.
50BF Setting (xIn) Test Current
(110%).............
(90%)...............
©2010 Siemens Protection Devices Limited
n/a
I (I ), I (I ), I (I ),
L1 A L2 B L3 C
50BF-n - Self Reset
50BF-1 Delay...............
No Operation
7SR224 Argus Commissioning & Maintenance Guide
50BF-2 Delay...................
□ No Operation
Chapter 6 Page 53 of 73
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