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System Setup and Setpoints – 4
4–85
When the Output Contact is open, and continuity
exists in the Trip Circuit, a small current flows that
activates the Trip Circuit Monitoring Input. If the
Trip Circuit is open, and the output contact is open,
no current flows and the Trip Circuit Monitoring
Input is deactivated. An Output Contact that is
welded closed would also cause the Trip Circuit
Monitoring Input to deactivate, indicating failure of
the Output Contact.
When the Output Contact is closed, no current
flows in the Trip Circuit Monitoring Input. If the
M-4272 has issued a trip command to close the
Output Contact and Trip Circuit Monitoring Input
remains activated, this is an indication that the
Output Contact failed to close.
The output of the Trip Circuit Monitoring function
can be programmed as an alarm to alert maintenance
personnel.
The M-4272 Trip Coil Monitor (TCM) will block all
transfers and illuminate the appropriate alarm LED
on the unit front panel when all of the following
conditions exist:
•
The M-4272 TCM is connected to the
target trip coil circuit.
•
The TCM Function is enabled.
•
An open condition has been detected in
the trip coil circuit for the duration of the
Time Delay.
TCM (TRIP CIRCUIT MONITOR)
Path:
System/Setup/Setpoints/TCM
Figure 4-91 displays the settings for the TCM (Trip
Circuit Monitor) function. The settings for the TCM
#2 Trip Circuit Monitor are the same as the TCM #1.
Enable/Disable
— The top right corner of the display
includes a command button that will disable or
enable the function. This selection allows the TCM
#1 (Trip Circuit Monitor) to be disabled (or enabled)
independent from the
TCM #2.
The TCM inputs are provided for monitoring the
continuity of the trip circuits. The inputs can be
used for nominal trip coil voltages of 24 V dc to 250
V dc. Trip circuit monitoring is performed in the
active breaker status only. Both the DC supply and
continuity for the circuit is monitored. If a trip coil is
detected as being open for the time delay then
transfers are blocked.
External connections for the Trip Circuit Monitoring
function are shown in Figure 4-90 and Figure 5-4.
The default Trip Circuit Monitor input voltage is 250
V dc. See Section 5.4,
Circuit Board Switches
and Jumpers
, (Table 5-3 for TCM#1, Table 5-5 for
TCM#2) for other available trip circuit input voltage
selections.
M-4272
Trip Circuit
Monitoring Input
Output
Contact
Station
Battery
+
-
Other
Contacts
52a
52
Trip
Coil
+
-
Figure 4-90 Trip Circuit Monitoring Input
Summary of Contents for M-4272
Page 1: ...Instruction Book Book 1 of 2 M 4272 Motor Bus Transfer System ...
Page 45: ...xviii M 4272 Instruction Book This Page Left Intentionally Blank ...
Page 200: ...System Setup and Setpoints 4 4 89 Figure 4 93 ISSLogic Function Dialog Screen ...
Page 207: ...M 4272 Instruction Book 4 96 This Page Left Intentionally Blank ...
Page 214: ...Declaration of Conformity Appendix I I 1 IAppendix I Declaration of Conformity ...
Page 215: ...M 4272 Instruction Book I 2 This Page Left Intentionally Blank ...