GE MI-869 Instruction Manual page 393

CHAPTER 4: SETPOINTS
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
current signal is multiplied by the corresponding phase or line voltage signal V
approach allows to increase the contrast between fault signature by shifting fault
characteristic frequency closer to the DC in the whole spectrum.
The FFT of the resultant multiplied signal is shown in the following figure. Comparison of
the two figures shows a clear contrast between fault signature and fundamental
frequency in coherent demodulated signal compared to only current FFT method signal.
Path:
Setpoints > Monitoring > Broken Rotor Bar
FUNCTION
Range: Disabled, Alarm, Latched Alarm, Configurable
Default: Disabled
The selection of Alarm, Latched Alarm or Configurable setting enables the Broken
Rotor Bar function. When the Alarm function is selected and the Broken Rotor Bar
operates, the LED "ALARM" flashes, and self-resets, when the operating conditions are
cleared.When the Latched Alarm function is selected, and the Broken Rotor Bar
operates, the LED "ALARM" flashes during the Broken Rotor Bar operating condition, and
is steady lit after the conditions are cleared. The LED "ALARM" is cleared by issuing the
reset command.When the Configurable function is selected, the ALARM LED does not
turn on automatically. They need to be configured using their own menus and flexlogic
operands.
MONITORING
*I . This
a a
4–275