GE MI-869 Instruction Manual page 242

PROTECTION
NOTE:
4–124
Figure 4-37: RTD Bias Curve
RTD BIAS VOTING
Range: Disabled, Enabled
Default: Disabled
The RTD biasing feature selects the maximum stator RTD temperature to calculate the
RTD Thermal Capacity Used. However, in the event of the malfunction of the maximum
temperature RTD, the RTD Bias Voting function assures extra security. This function
requires another stator RTD to be voted with the maximum temperature RTD.
Maximum stator RTD temperature will be used by the RTD Biasing feature only if both
maximum stator RTD temperature and voting RTD temperature, which is the second
maximum temperature, lie within the range defined by the setpoint RTD Bias Voting
Band. If the maximum stator RTD temperature and voting RTD temperature don't lie
within the settable range than next maximum stator RTD temperature will require voting
by the next voting RTD. If voting fails, RTD Bias feature will block automatically.
At least two RTDs have to be configured as Stator type (under Setpoints/Monitoring/RTD
Temperature) for this feature to become active.
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS