Basler Electric BE1-87G - Manual (Page 27)

Comparator
The comparator provides the variable percentage characteristic of the relay as follows.
Restraint Current Less than Nominal
When I
R
is less than nominal (5 Aac for sensing input range 1 or 1 Aac for sensing input range 2), the
comparator provides an output signal whenever I
OP
exceeds the front panel sensitivity setting.
Restraint Current Greater than Nominal
When I
R
is greater than nominal (5 Aac for sensing input range 1 or 1 Aac for sensing input range 2), the
front panel sensitivity switch setting (threshold) is increased by adding it to a scaled value representing
one half of I
R
minus nominal (5 Aac for sensing input range 1 or 1 Aac for sensing input range 2).
Output Relays
When the current difference exceeds the variable percentage limit (sensitivity switch setting), the
comparator output energizes the output relays. (In BE1-87G models with three-phase sensing, the
outputs are ORed together so that the output relays energize if the current difference of any one phase
exceeds the limit.) When the current difference decreases below 90% of the variable percentage
threshold, the output relays reset.
Main Output Relay
The main output relay contacts are either normally-open or normally-closed and are accessed at case
terminals 1 and 10. Normally-open contacts are provided on BE1-87G relays with a style number of xxE-
xxx-xxxxx and normally-closed contacts are provided on relays with a style number of xxG-xxx-xxxxx.
Auxiliary Output Relay (Optional)
An optional pair of contacts, accessed at case terminals 2 and 5, can be specified. The auxiliary output
contacts change state when the main output contacts operate and are available in a normally-open or
normally-closed configuration. Normally-open auxiliary contacts are provided on BE1-87G relays with
style number xxx-xxx-xxx1x and normally-closed auxiliary contacts are provided on relays with style xxx-
xxx-xxx2x.
Optionally, the auxiliary output relay can be specified to function as a power supply status output. This
normally-closed output is energized open during normal operation. When relay control power is lost or an
internal power supply failure occurs, the relay de-energizes and closes the contacts at terminals 2 and 5.
Target Indicators (Optional)
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. Latched targets are reset
by operating the target reset switch on the front panel. If relay operating power is lost, any 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. Both target
types are reset by operating the target reset switch.
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 circuits.
Current Operated Targets
Current operated targets are triggered by closure of the corresponding output contact and the presence of
at least 200 milliamperes of current flowing in the trip circuit.
NOTE
Prior to September 2007, the BE1-87G target indicators consisted of
magnetically latched, disc indicators. These mechanically latched target
indicators have been replaced by the electronically latched LED targets in use
today.
9170800990 Rev N BE1-87G Functional Description 3-3