Basler BE-51/27C, Instruction Manual, Page: 24 / 53

BE1-51/27C Functional Description
3-4
Voltage Inhibit
The output of the multiplexor is applied to the voltage inhibit circuit for comparison with a voltage limit set
by the front panel
VOLTAGE INHIBIT ADJ control. If the (phase) input voltage exceeds this level, the
appropriate front panel VOLTAGE INHIBIT indicator will be illuminated and a voltage inhibit signal will
prevent the timed output relay and (if present) the auxiliary output relay from energizing. Instantaneous
overcurrent operation, if present, will not be affected.
Instantaneous Overcurrent (Options 1-1 and 1-2)
Input current levels applied to the time overcurrent circuitry are also passed to the instantaneous overcurrent
circuitry. These levels are compared to the setting of the front panel
INST 1
adjust and the front panel
INST
1 (NEUTRAL)
adjust (if present). If the input current level is above the setting, the output driver energizes
the instantaneous 1 Output Relay. If the instantaneous 2 option is present, the input level is also compared
with the setting of the front panel
INST 2 adjust to energize the instantaneous 2 output relay. Note that the
current level settings for the instantaneous overcurrent element will always be from 1 to 40 times above the
front panel
TAP
and
TAP (NEUTRAL)
settings of the time overcurrent element.
If target type A or B is present, the front panel INST 1 target and the front panel INST 2 targets are tripped
when their respective output relay is energized, along with the front panel A, B, C, or N ELEMENT targets
(if present) associated with the detected phases. (See Section 2 for the types of targets that can be present
depending upon the relay configuration.)
Timed and Instantaneous Outputs
Each output signal (representing either time overcurrent or instantaneous overcurrent) from each monitored
phase (or neutral) is applied to the respective output driver. Each output driver supplies operating current
to energize it associated output relay. Either normally open (output type E) or normally closed (output type
G) contacts may be specified. (The contact configurations of all output relays for a given model will be the
same.)
Auxiliary Outputs
In addition to the output relays, an auxiliary relay, having the same or a different contact configuration, may
be specified. Both the output and the auxiliary relays will remain energized for the duration of the
overcurrent condition.
Push-to-Energize Pushbuttons
If either option 2-C or 2-E is present, each individual output relay can be directly energized for test purposes
by the actuation of a front panel
PUSH-TO-ENERGIZE OUTPUT
pushbutton. The pushbutton is actuated
by the insertion of a thin, non-conducting rod through an access hole in the front panel.
Power Supply Status Output (Option 3-6)
Power supply status output relays have a set of normally closed contacts that are energized open during
power-up. If either or both power supply output legs (+12 Vdc or -12 Vdc) fails, the power supply status
output relay is de-energized and the output contacts close. Shorting bars across the output contacts are
held open by the installed connection plug. When the relay is removed from service by removing the
connection plug, the shorting bars are closed.
Target Indicator Circuits
When specified, a front panel target indicator for each type of monitoring (i.e., time overcurrent or instan-
taneous) will be supplied. Two types of target drive circuits are available: