BE1-51/27R - Human Machine Interface (Controls And Indicators)
2-1
SECTION 2 • HUMAN MACHINE INTERFACE
(Controls And Indicators)
GENERAL
Table 2-1 lists and briefly describes the human machine interface (HMI) of the BE1-51/27R Time
Overcurrent Relay with voltage restraint. Reference the call-out letters to Figure 2-1.
Table 2-1. Controls and Indicators
Letter
Control or Indicator
Function or Indicator
A
TAP NEUTRAL Selector
Provides selection of the neutral overcurrent pickup point
in conjunction with the front panel NEUTRAL CAL
control.
B
PHASE - TAP Selector
Provides the selection of the overcurrent pickup point in
conjunction with the front panel TAP CAL control.
C
CAL NEUTRAL Control (On
Relays with Phase-and-
Neutral Sensing Only)
A single turn potentiometer provides adjustment of the
neutral overcurrent pickup point between the selected tap
setting and the next lower tap setting.
Not
Shown
TAP RANGE Plate High/Low
Plate position indicates the terminal connections (high or
low) used to select the current sensing input range. Refer
to Table 2-2 for sensing input ranges.
D
TIME DIAL NEUTRAL (If
present)
Determines the time delay between sensing of the
overcurrent condition and the closing of the output relay.
Refer to Section 1 and Table 2-3 for curve selection
information.
E
TIMING NEUTRAL (If pres-
ent)
LED illuminates when the neutral pre-set overcurrent
pickup point is reached and exceeded.
F
Time Current Characteristic
Curve Selector (Z1, Z2, and
Z3 Timing Options Only)
Provides selection of the time current characteristic
curves. Refer to Section 1 and Table 2-3 for curve
selection information. Cutaway view shows switch behind
the front panel.
G
POWER Indicator
LED illuminates to indicate that the relay power supply is
functioning.
H
Target Reset Lever
Manually resets all targets (both element and function
type).
I
FUNCTION Targets TIME
INST1, INST2*
Front panel FUNCTION targets trip when the
corresponding output relay is energized by an overcurrent
condition.
J
ELEMENT Targets
Front panel ELEMENT targets trip when an output relay is
energized by an overcurrent condition.