Basler BE1-50BF, Инструкция по эксплуатации

Страница: 26 / 47

3-2 BE1-50BF Functional Description 9190600990 Rev F
output relays remain enabled until the control timer times out, and reset when the control timer times out.
If S1-3 is open, instantaneous output relays remain enabled only for the period of time that the BFI or
supervisory contacts are closed. Two instantaneous output relays are provided.
Control Timer
The control timer provides a window of opportunity for a breaker failure output. Control timer cycles are
initiated by either a BFI or supervisory input signal. For the breaker failure output contacts to close as
shown in Figure 3-2, the sensed current must be in excess of the pickup setting. Note that all output
relays, if operated, are restored at the end of the control timer cycle.
To facilitate setting the relay, four oscilloscope test jacks are provided on the front panel (A through D,
Figure 2-1). These jacks are completely isolated from all other circuits.
Figure 3-2. Control Timer Cycle
Timer T1 and T2
Timers T1 and T2 provide (independently) an adjustable time delay to allow current to decay after the
breaker is tripped. If sensed current is in excess of the pickup setting and the timer times out while the
window of opportunity is present (before the control timer times out), the BF output contacts will close.
Field Programmable Logic
Field programmable switch S1 is an eight section switch (S1-1 through S1-8) that allows the relay to be
reconfigured to meet changing requirements. Switch S1 is located on left side of the logic board and is
accessible by withdrawing the cradle assembly from the case. The purpose of each switch section is
explained in detail in Section 2.
Outputs
Breaker failure output relays, BF1 through BF3, are simultaneously operated when the associated logic
AND function receives qualifying signals.
Current Sensing
Monitored line currents are applied to the Primaries of internal current transformers and stepped down to
internal circuit levels Transformers provide a high degree of isolation.
Current Pickup Detector
Each sensing input is fed to both a positive and negative half cycle pickup detector. Each detector will
provide an output when the sensing current increases to a level greater than the pickup setting.
Current Pickup Indicator
Each current pickup detector provides an input to the current pickup indicator. The current pickup
indicator turns ON the LED for 22 milliseconds after the most recent input. Outputs are approximately
every eight milliseconds for the duration of time that the sensing current is above the pickup setting.