Basler Electric BE1-51/27C - Manual (Page 19)

9137200998 Rev E 13
Microprocessor (Not Shown)
Some of the circuitry already discussed is part of the microprocessor and no definite lines are drawn to
separate the functions. The microprocessor compares the desired time delay (from the time trip
comparator and scaler) with the actual elapsed time from the counter. When the elapsed time reaches the
intended delay, the timed output relay is energized. During the time delay period, the front panel TIMING
indicator (i.e. pickup) associated with the detected phase is illuminated.
If targets are present, the front panel TIME FUNCTION target will be tripped, and the A, B, C, or N
ELEMENT target associated with the detected phase will be tripped. See the Controls and Indicators
chapter for the types of targets that are present (depending upon relay configuration).
If option 3 is present, an auxiliary output relay (with N.O., N.C., or SPDT contacts) is also actuated when
the timed output relay energizes.
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 the Controls and Indicators chapter 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 the 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
BE1-51/27C Functional Description