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4-12
469 Motor Management Relay
GE Power Management
4.3 S2 SYSTEM SETUP
4 SETPOINT PROGRAMMING
4
b) EXAMPLES
1.
Given the following specifications: Motor Nameplate FLA: 87 A, Low Resistance Grounded, Maximum
Fault: 400 A, 469 purchased with 5 A phase CT Secondary, Ground
Fault Detection to be Residual
Make the following settings:
PHASE CT PRIMARY:
"100"
MOTOR FULL LOAD AMPS:
"87"
GROUND CT: "
5 A Secondary"
GROUND CT PRIMARY:
"100"
2.
Given the following: Motor Nameplate FLA: 255 A, Solidly Grounded, Maximum Fault: 10000 A, Zero
Sequence Ground CT: (10000/20) 500:1
Make the following settings:
PHASE CT PRIMARY:
"300"
MOTOR FULL LOAD AMPS: "
255"
GROUND CT:
"5 A Secondary"
GROUND CT PRIMARY:
"500"
3.
Given the following: Motor Nameplate FLA: 330 A, High Resistance Grounded, Maximum Fault: 5 A
Make the following settings:
PHASE CT PRIMARY: "
350"
MOTOR FULL LOAD AMPS:
"330"
GROUND CT:
"Multilin 50:0.025"
4.3.2 VOLTAGE SENSING
The manner in which the voltage transformers are connected must be entered here. A value of
"None"
indicates
that no voltage measurement is required. Note that phase reversal is disabled for single VT operation. All volt-
ages are assumed balanced. Also, frequency is only available for AN or AB connections.
If voltage measurements are to be made, the turns ratio of the voltage transformers must be entered. The
VOLTAGE TRANSFORMER RATIO
must be chosen such that the secondary voltage of the VTs is between 40 and
240 V when the primary is at
MOTOR NAMEPLATE VOLTAGE
. All voltage protection features that require a level
setpoint are programmed as a percent of the
MOTOR NAMEPLATE VOLTAGE
or rated voltage, where
MOTOR NAME-
PLATE VOLTAGE
represents the rated design voltage line to line.
For example, given the following specifications: the Motor Nameplate Voltage is 4160 V
the VTs are 4160/120 Open Delta
Set:
VT CONNECTION TYPE:
"Open Delta"
VT RATIO:
"34.67:1"
MOTOR NAMEPLATE VOLTAGE:
"4160"
y
VOLTAGE SENSING
y
[ENTER] for more
VT CONNECTION TYPE:
None
Range: Open Delta, Wye, None
ENABLE SINGLE VT
OPERATION: OFF
Range: AN, BN, CN, OFF or AB, CB, OFF.
Seen only if VT Connection Type is Wye or Open Delta
VOLTAGE TRANSFORMER
RATIO: 35.00:1
Range: 1.00:1 to 300.00:1, step: 0.01
MOTOR NAMEPLATE
VOLTAGE: 4000 V
Range: 100 to 20000 V, step: 1
ENTER
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