Basler Electric BE1-50/51B-230 - Manual (Page 30)

3-2 BE1-50/51B-230/-234/-239 Functional Description 9252000894 Rev H
RC time constant. This provides information from the integrating reset function even when power has
been entirely removed.
The microprocessor defines the relay operating parameters based on inputs received from the Time
Overcurrent Time Dial Selector, Curve Selector, and four-position slide switch. The microprocessor
determines the level of sensed current by a digital signal supplied by the analog-to-digital converter.
Sensed current that exceeds the setting of the Time Overcurrent Pickup Selector switches causes the
Active/Pickup LED color to change from green to red and the 51 Trip output contacts to close in
accordance with the time characteristic equation. Sensed current exceeding the Instantaneous
Overcurrent A Pickup selector switch setting causes the 50-A Trip output contacts to close. Likewise,
sensed current exceeding the Instantaneous Overcurrent B Pickup selector switch setting causes the 50-
B Trip output contacts to close.
Outputs
Each protective element (time overcurrent (51), instantaneous overcurrent A (50-A), and instantaneous
overcurrent B (50-B)) is equipped with a set of normally-open contacts rated for tripping duty. A system
circuit breaker controlled by the 51 or 50-A output contacts can be manually tripped by connecting a
jumper across the Time Overcurrent Manual Trip jacks or the Instantaneous Overcurrent Manual Trip
jacks. (Manual trip jacks are not provided for the system circuit breaker controlled by the 50-B output
contacts.) Current flow in a trip circuit is indicated by operation of the corresponding target. The targets
will not operate without adequate relay operating power.
WARNING!
Trip circuit voltage is present at the front panel trip jacks. When shorting the
trip jacks, use insulated jumpers to avoid contact with these voltages.
Target Indicators
Gravity-latched, manually-reset, current-operated target indicators are provided for the time overcurrent
(51) trip output and the instantaneous overcurrent A (50-A) trip output. A target indicator is not provided
for the 50-B trip output. The level of trip circuit current required to operate each target is individually
controlled by a circuit board jumper. The minimum operating current range can be set for 80 to 200
milliamperes or 0.9 to 2.25 amperes. See Section 2, Controls and Indicators for jumper locations and
function assignments.