GE Industrial Solutions EntelliGuard TU Trip Units - Manual (Page 31)

DEH-4567B EntelliGuard TU Trip Units: UL/ANSI Models
Protection
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There is an option bell alarm contact accessory that
provides a signal whenever the breaker’s mechanical
lockout operates. In MANUAL mode this contact will remain
closed as long as the lockout reset button is extended. In
AUTO mode this contact will close briefly when a trip
occurs, but does not latch. The dwell time of the contact in
AUTO mode is on the order of a few milliseconds – typically
not enough to be useful for control purposes.
DIGITAL INPUT RELAYS
Inputs can be assigned to three main functionalities:
• Reduced Energy Let-Through (RELT)
• Trip the breaker
• Remotely reset latched relays
Table 2-16 shows the possible assignments for the inputs.
Input 1:
• If the trip unit is equipped with the Reduced Energy Let
Through (RELT) protection feature, this input is
automatically and permanently assigned to engage
RELT settings when the input is activated.
• If RELT is not available on the trip unit, Input 1 can be
set to OFF (no action), Trip the Breaker, or Reset latched
output relays.
Input 2: (EntelliGuard G only)
• RELT, RESET, TRIP, and OFF.
Table 2-16: Digital Input Assignments
Input Input 1
Assignment
Summary Description
1 OFF No action taken.
RESET Resets Latched Output Relays
RELT Causes unit to use the RELT
protection setpoints as long
as input 1 is active.
TRIP Causes the breaker to trip.
2 OFF No action taken.
RESET Resets Latched Output Relays
RELT Causes unit to use the RELT
protection setpoints as long
as input 2 is active.
TRIP Causes a breaker to trip.
NOTICE
High fidelity external contacts are recommended for
use with inputs to reduce the likelihood of contact
bounce being interpreted as multiple input commands.
In addition to the Digital Inputs indicated above, Power
Break I, Power Break II, WavePro, AKR, and EntelliGuard G
Trip Units also receive inputs from external voltage
conditioners, a +24 VDC control power supply, and
communication connections. (External +24 VDC control
power is required for communication.)
All trip unit types have a connection to an auxiliary switch
within the breaker that senses the breaker’s contact
position (OPEN or CLOSED). This status indication requires
+24 VDC.