Basler Electric BE1-25 - Manual (Page 37)

Voltage Monitor Options
Voltage monitor options are shown in the lower portion of Figure 3-1, and described in the following
paragraphs.
Filters
Input voltages from bus and line are filtered and applied to the peak detectors or average detector
circuitry.
Peak Detectors (Option 2-R, 2-T, or 2-U)
Voltage difference (∆V) peak detectors measure the phasor voltage difference between line and bus, and
compare this difference against the setting of the front panel ∆V control. If the detected difference is less
than the limit, the sync-check timer is enabled, and the front panel ∆V LED is lighted.
Four additional peak detectors compare the sensed line and bus voltages with reference voltages
established by the front panel control settings. To illustrate operation, let us first consider the two upper
peak detectors, noting that they monitor the bus, and that one of them has its output inverted.
When the live bus (LB) peak detector determines the sensed bus voltage is above the threshold voltage,
it outputs a logic-high signal to the selection logic. But the DB/Not Overvoltage peak detector, because of
inversion, only provides a logic-high signal when sensed voltage is below the threshold, thereby
identifying either a dead bus (i.e., Mode Switch No. 1 is Up to select the NORMAL Mode), or a Not
Overvoltage condition (Mode Switch No. 1 is Down to select the NOT OV Mode).
The lower pair of peak detectors works in similar fashion to define line conditions, as determined by the
position of Mode Switch No. 2.
Average Detectors (Option 2-A, 2-B, or 2-C)
Voltage difference average detectors provide the same functionality as the peak detector inputs except
they measure the average voltage difference instead of phasor voltage difference.
Selection Logic
Voltage monitor selection logic is controlled by Mode and Condition switches or External Condition
Switches to produce the Voltage Monitor output.
Another output from the voltage monitor selection logic serves as an additional qualifier for the timer in the
sync output circuit. The specific conditions being monitored depend upon whether NORMAL or NOT OV
operation is used. Live line and live bus is monitored if NORMAL Mode is selected. Live line, live bus, and
Not Overvoltage is monitored if NOT OV Mode is selected.
Detailed instructions and precautions for programming the Mode and Condition switches are provided in
Table 2-1, callouts R and S. The location of the switches is shown in Figure 2-2.
Target Indicator
A target indicator is an optional component selected when a relay is ordered. The electronically latched
and reset target consists of a red LED indicator 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, an illuminated
(latched) target is extinguished. When relay operating power is restored, the previously latched target is
restored to its latched state.
A relay can be equipped with either an internally operated target or a current operated target.
Internally Operated Target
The relay SYNC output is directly applied to drive the target indicator. The indicator is illuminated
regardless of the amount of current flowing through the output contact.
Current Operated Target
A current operated target is triggered when at least 200 milliamperes of current flows through the SYNC
output contact.
NOTE
Prior to September 2007, BE1-25 the target indicator consisted of a magnetically
latched, disc indicator. This mechanically latched target indicator has been
replaced by the electronically latched LED target in use today.
9170200990 Rev U BE1-25 Functional Description 3-3