9171300990 Rev R
BE1-87T Controls and Indicators
2-1
SECTION 2 • CONTROLS AND INDICATORS
LOCATION OF CONTROLS AND INDICATORS
Table 2-1 lists and briefly describes the operator controls and indicators of the BE1-87T Transformer
Differential Relay. Reference the call-out letters A through M to Figures 2-1 to 2-3; N through Q to Figure
2-5. Exploded views of controls that are mounted inside the relay (call-out letters B, D and I) are shown in
Figure 2-4.
Table 2-1. Controls and Indicators
Letter
Control or Indicator
Function
A
INPUT
(or TAP) Switches
Front panel
INPUT
switches are used to scale the
transformer currents. There are two of these rotary
switches for each input.
1 Ampere CT Units
Each of the upper switches is calibrated to represent
the tenths and units digits (0
.
4 through 1
.
6) of tap
value. Each of the lower switches is calibrated to
represent two-hundredths of tap value for each
increment. Always add the setting of the lower switch to
that of the upper switch. For example, if a setting of
1
.
02 is desired, the upper switch must be at 1
.
0 and the
lower switch must be at 0
.
02. The total setting range for
each input is 0
.
4 to 1
.
78.
5 Ampere CT Units
Each of the upper switches is calibrated to represent
the units digit (2 through 8) of tap value. Each of the
lower switches is calibrated to represent tenths of tap
value. Always add the setting of the lower switch to that
of the upper switch. For example, if a setting of 5.0 is
desired, the upper switch is set to 5
.
0, the lower switch
must be at 0
.
0. The total setting range for each input is
2
.
0 to 8
.
9.
B
30° Phase Shift Jumpers
(three-phase units ONLY)
These jumpers control the internal phase shift of the
relay, 30°, -30°, or 0°, depending upon the
position of the jumpers provided for each input on the
Analog #2 Board, shown in Figure 2-4. Additional
information is in Section 4.
C
UNRESTRAINED PICKUP
LEVEL
Switches
This thumbwheel switch establishes the desired pickup
setting for all phases of the unrestrained output. The
adjustment range is from 6 to 21 times the phase tap
setting, in increments of 1.
D CALIBRATE
Switch
(three-phase units ONLY)
A two-position switch is located on each Analog #1
Board and is easily accessible on the right side of the
relay when it is withdrawn from the case. In the
CALIBRATE
position, these switches inhibit the
harmonic share feature when calibrating the 2nd
Harmonic Restraint. In the
NORMAL
position, the relay
will operate normally.
E
POWER
Indicator
This LED will illuminate when operating power is
supplied to the internal circuitry of the relay.
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