Basler Electric BE1-50 - Manual (Page 18)

PICKUP SETTINGS
A front panel multiple-turn potentiometer controls the pickup setting for all phases. The potentiometer
establishes the reference voltage representative of the system current, which will cause the relay to
respond. On relay styles monitoring neutral current, an independent potentiometer is provided to establish
the pickup level for neutral.
PICKUP COMPARATORS
The magnitude of each monitored current is compared with the appropriate pickup setting. When a pickup
setting is exceeded, a pulse stretcher for that phase (or neutral) is activated.
PULSE STRETCHERS
Because the sensed currents are full-wave rectified and minimally filtered to retain high-speed operation,
the pulse output from the comparators must be extended.
OUTPUTS
Defined by the style number, individual output relays may be provided for each monitored phase (and
neutral). One output relay may serve for all monitored phases (and neutral). In addition, one auxiliary
output relay may be provided that serves for all monitored phases (and neutral).
PUSH-TO-ENERGIZE OUTPUT PUSHBUTTONS
Small pushbutton switches may be provided as an option to allow testing the primary output contacts and
(if present) the auxiliary output contact. To prevent accidental operation, the pushbuttons are recessed
behind the front panel and are depressed by inserting a thin, non-conducting rod through an access hole
in the front panel.
POWER SUPPLY STATUS OUTPUT
The optional power supply status relay has a set of normally closed contacts and energizes when
operating power is applied to the BE1-50. If relay operating power is lost or one side of the power supply
output (+12 Vdc or –12 Vdc) fails, the power supply status relay de-energizes and closes the power
supply status output contacts. If the power supply status output is provided, then the auxiliary contact is
not available.
POWER SUPPLY
Operating power for the relay circuitry is supplied by a wide range, electrically isolated, low-burden power
supply. Power supply operating power is not polarity sensitive. The front panel power LED and power
supply status output indicate when the power supply is operating. Power supply specifications are listed in
Table 1-2.
TARGET INDICATORS
Target indicators are optional components selected when a relay is ordered. The electronically latched
and reset targets consist of red LED indicators located on the relay front panel. A latched target is reset
by operating the target reset switch on the front panel. If relay operating power is lost, illuminated
(latched) targets are extinguished. When relay operating power is restored, the previously latched targets
are restored to their latched state.
A relay can be equipped with either internally operated targets or current operated targets.
Internally Operated Targets
The relay trip outputs are directly applied to drive the target indicators. The indicators are illuminated
regardless of the current level in the trip circuit.
3-2 BE1-50 Functional Description 9171000990 Rev F