GE 869 Instruction Manual page 421

CHAPTER 4: SETPOINTS
NOTE:
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
During monitoring mode ESA algorithms for bearing, mechanical and stator faults are
computed every 1 minute based on current (Ia) samples. FFT is run on these current (Ia)
samples to capture the peak magnitude or energy for each possible harmonic factor (k =
1,2,3) related to bearing, mechanical and stator faults, and stored in an internal file for
each load bin. Computed ESA dB magnitudes at all fault frequencies after each interval are
compared with baseline magnitudes to extract the maximum change in dB. Both data
quality checks and ESA accuracy checks are performed prior to recording data. Users can
clear operational data using the 'Clear ESA operational data' command.
System\ Motor\ Setup
ESA computation uses some of the existing settings already available in 869. The following
are the settings (shown with their path location) that must be configured.
• Number of Poles
this setting from section System\ Motor\ Setup is used to compute synchronous
speed. (Mandatory)
• Motor Rated Horse Power and Motor Rated Efficiency
these settings from section System\ Motor\ Setup are used to compute Rated input
power that in turn is used for speed estimation. (Mandatory)
• Nominal frequency
this setting from section Platform\ Frequency 1-J (or 2-K) is used to compute
frequency variation in the case of data quality check. (Mandatory)
• Frequency tracking
this setting from section Settings\ Power System if enabled is used to compute source
frequency more accurately. Enabling this setting is recommended. (Optional)
• Rated speed
this setting from section Path: Monitoring\ Tachometer is used for speed estimation.
(Mandatory)
Path: Setpoints > Monitoring > ESA
Some of the existing settings in 869 as mentioned in the preceding list will be re-used for
ESA computation hence it is necessary to configure them. Since ESA is dependent on
speed and frequency, it is mandatory to configure the rated speed. In addition, frequency
tracking must be enabled for accurate ESA results.
MOTOR MANUFACTURER
Range: n/a
Default: None
Configure the name of the motor manufacturer as a character string using the
information taken from the motor nameplate data.
FUNCTION - BEARING
Range: Disabled, Enabled
Default: Disabled
When the Enabled function is selected, the element checks for the Bearing (Eccentricity)
Fault status as programmed.
FUNCTION - MECHANICAL (MECH)
Range: Disabled, Enabled
Default: Disabled
When the Enabled function is selected, the element checks for the mechanical (FEM)
Fault status as programmed.
MONITORING
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