GE 869 - Page 269

CHAPTER 4: SETPOINTS PROTECTION
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL 4–137
Figure 4-47: Thermal Model logic diagram
894102A3.cdr
SETPOINTS SETPOINTS
FLEXLOGIC OPERANDS
MOTOR STATUS
ACTUAL VALUE
THERMAL MODEL BLOCK:
EMERGENCY RESTART:
THERMAL PKP
MOTOR RUNNING
MOTOR STOPPED
ACTUAL VALUES
MOTOR OVERLOAD
MOTOR STARTING
Phase Currents
STATOR TEMP SENSOR 1 STATOR TEMP SENSOR 2 STATOR TEMP SENSOR 3 STATOR TEMP SENSOR 4 STATOR TEMP SENSOR 5 STATOR TEMP SENSOR 6
COOL TIME CONSTANT RUNNING: RTD BIAS CENTER POINT: TD MULTIPLIER: RTD BIAS MINIMUM: THERMAL MODEL CURVE: RTD BIAS:
IA RMS IB RMS IC RMS Pos Seq I Neg Seq I Off=0
Off=0
Configurable
OR
AND
OR
COOL TIME CONSTANT STOPPED:
RTD BIAS MAXIMUM:
RUN
RTD TC
used
%
Reset TC Used To 0%
Max Temp
Hottest RTD
Ieq ≥ OL x FLA
SETPOINTS
SETPOINTS
TRIP FUNCTION:
Disabled=0
Trip
OR
FLEXLOGIC OPERAND
THERMAL TRIP OP
AND AND AND
Operate Output
Relay 1(TRIP)
LED: TRIP
OR
LED: ALARM
LATCH
S
R
RESET
Command
t
I
TC
used
%
From Voltage Dependent
Curve Selection Logic
Scheme
SETPOINTS
ALARM FUNCTION:
Disabled=0
Alarm Latched Alarm
OR
TC
used
≥ Alarm
Pickup
FLEXLOGIC OPERAND
THERMAL ALARM OP
SETPOINT
Alarm Output Relay X
Do Not Operate, Operate
ANDAND
SETPOINT
Trip Output Relay X
Do Not Operate, Operate
OR
AND
Ieq < OL x FLA
MOTOR TRIPPED
AND
RTD BIAS VOTING:
RTD BIAS VOTING BAND:
TCused≥ 100%
>
RTD TCused ≥
100%
LATCH
R S
RESET
Command
Reset Dominant