GE Power Management
469 Motor Management Relay
4-11
4 SETPOINT PROGRAMMING
4.3 S2 SYSTEM SETUP
4
4.3 S2 SYSTEM SETUP
4.3.1 CURRENT SENSING
a) FUNCTION
As a safeguard,
PHASE CT PRIMARY
and
MOTOR FULL LOAD AMPS
are defaulted to
"Not Programmed"
when shipped
from the factory. A block start indicates that the 469 was never programmed. Once
PHASE CT PRIMARY
and
MOTOR FULL LOAD AMPS
are entered, the alarm resets itself. The phase CT should be chosen so the FLA is no
less than 50% of the rated phase CT primary. Ideally, the phase CT primary should be chosen so the FLA is
100% of the phase CT primary or slightly less, never more. The secondary value of 1 or 5 A
must
be specified
at the time of order so that the proper hardware is installed. A value for
MOTOR FULL LOAD AMPS
(FLA) must
also be entered. The value may be taken from the motor nameplate data sheets. The Service Factor may be
entered as Overload Pickup (see Section 4.6: S5 THERMAL MODEL on page 4–26).
For high resistance grounded systems, sensitive ground current detection is possible if the 50:0.025 ground
CT input is used. To use the 50:0.025 input, select
"Multilin 50:0.025"
for the
GROUND CT
setpoint. No additional
ground CT messages will appear. On solidly grounded systems where fault currents may be quite large, the
469 1A or 5A secondary ground CT input should be used for either zero-sequence or residual ground sensing.
If the connection is residual, the Ground CT secondary and primary values should be the same as the phase
CT. If however, the connection is zero-sequence, the Ground CT secondary and primary values must be
entered. The Ground CT primary should be selected such that potential fault current does not exceed 20 times
the primary rating. When relaying class CTs are purchased, this precaution will ensure that the Ground CT
does not saturate under fault conditions.
The
PHASE DIFFERENTIAL CT PRIMARY
setpoint must be entered if the differential feature is to be used. If two CTs
are used per phase in a vectorial summation configuration, the CTs should be chosen to ensure there is no sat-
uration during motor starting. If however, a core balance CT is used for the differential protection in each
phase, a low CT rating of 50 or 100 A allows for very sensitive differential protection.
When the two-speed motor feature is used, a value for a second set of Phase CTs and motor FLA must be
entered here for Speed 2. If the Phase CTs are the same as the speed 1 phase CTs, simply enter the same
value here as well.
y
CURRENT SENSING
y
[ENTER] for more
PHASE CT PRIMARY:
Not Programmed
Range: 1 to 5000 A step 1, Not Programmed
MOTOR FULL LOAD AMPS
FLA: Not Programmed
Range: 1 to 5000 A step 1, Not Programmed
GROUND CT:
Multilin 50:0.025
Range:
None, 1A Secondary, 5A Secondary, Multilin 50:0.025
GROUND CT PRIMARY:
100 A
Range:
1 to 5000 A; Step: 1. Seen only if the
GROUND CT
setpoint above is
"1A Secondary"
or
"5A Secondary"
PHASE DIFFERENTIAL
CT: None
Range:
None, 1A Secondary, 5A Secondary
PHASE DIFFERENTIAL
CT PRIMARY: 100 A
Range:
1 to 5000; Step: 1. Seen only if the
GROUND CT
setpoint
above is
"1A Secondary"
or
"5A Secondary"
ENABLE 2-SPEED MOTOR
PROTECTION: No
Range: No, Yes
SPEED2 PHASE CT
PRIMARY: 100 A
Range:
1 to 5000 A step: 1.
Seen only if 2-Speed motor protection is enabled.
SPEED2 MOTOR
FLA: 1 A
Range:
1 to 5000 A; step: 1
Seen only if 2-Speed motor protection is enabled.
ENTER
ESCAPE
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