3-2
BE1-87T Functional Description
9171300990 Rev R
Figure 3-1. Functional Block Diagram
NOTES
1 Present in three-phase units ONLY.
2 Inputs 4 and 5 are available in single-phase units ONLY.
3 The settings are calibrated to a specified percentage of the harmonic to the fundamental. See
Harmonic
Restraints
for factory settings.
4 Phase Targets are supplied on three-phase units ONLY.
5
Restrained
Trip
Contact:
•
One contact for single-phase units.
•
One contact or one contact per phase available on three-phase units.
6
Three-phase units use the sum of the second harmonic from each phase to restrain each phase.
7
Phase Targets are supplied on three-phase units ONLY.
8 Restrained
Trip
Contact:
•
One contact for single-phase units.
•
One contact or one contact per phase available on three-phase units.
B
C
4
RESTRAINED
UNRESTRAINED
RESTRAINED
UNRESTRAINED
TARGET
TARGET
B SAME AS A
0
0
OR
OR
B
0
C
0
C SAME AS A
0
0
0
0
OPTIONAL
RESTRAINED
CONTACTS
FOR EACH OF
3 PHASES
(SEE NOTE 5
BE1-87T
D741-001b
7-11-94
COM.
IN. 1
IN. 2
IN. 3
COM.
IN. 1
IN. 2
IN. 3
0B
0 C
Figure 3-2. Functional Block Diagram, Phase B and Phase C
S2
S1
IN. 3, B SCALE
IN. 3, C SCALE
0
0
IN. 1, B SCALE
IN. 1, C SCALE
0
0
OPERATING
POWER
POW ER
SUPPLY
POW ER
SUPPLY
STATUS
5
REST.
TRIP
AUX.
OPTION
UNREST
TRIP
TARGET
UNRESTRAINED
B
RESTRAINED
6
POWER
TO INTERNAL
CIRCUITRY
Iop
1
SHIFT SETTING:
+30°, -30°, 0°
8
LEDs
CALCULATE
MAXIMUM
INDIVIDUAL
CURRENT
THEN TRIP
op
I
IF
>% max
I
% OF
TRIP
UNREST. SETTING
COM.
IN. 1
IN. 2
IN. 3
IN. 4
IN. 5
TO OTHER PHASES
(THREE-PHASE ONLY)
UNREST
TRIP
(6 TO 21
TIMES TAP)
2
0
30 °
SHIFT
(ONLY ON
3 UNITS)
0
0
SCALING
( TAP)
SCALING
( TAP)
SCALING
( TAP)
IN. 2, B SCALE
IN. 2, C SCALE
0
0
SCALING
( TAP)
0
C
0
5TH >
SETTING
=INHIBIT
3
2ND >
SETTING
=INHIBIT
3
OR
B
C
0
0
4
TARGET
TARGET
SCALING
( TAP)
POWER
SUPPLY
SENSOR
FIFTH
HARMONIC
RESTRAINT
FILTERS
SECOND
HARMONIC
RESTRAINT
FILTERS
SUMMING:
ALGEBRAIC
SUM OF
INPUTS =
OPERATING
CURRENT
( )
Iop
OR
30 °
SHIFT
(ONLY ON
3 UNITS)
0
0
30 °
SHIFT
(ONLY ON
3 UNITS)
0
0
2
max
I
% I max
REST.
T
PICKUP
CONTROL
% Imax
op
I
UNREST.
SETTING
THEN TRIP
IF I >
op
A
OR
1 0
0
BE1-87T
D741-001a
7-11-94
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