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CHAPTER 4: SETPOINTS
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
MAXIMUM CURRENT UNBALANCE
Range: 0.0 to 100.0%
Default: 15.0%
This setting is used to block the data acquisition of the Broken Rotor Bar detection
function, as long as the current unbalance is above this setting. The Broken Rotor Bar
detection algorithm cannot accurately determine the BRB spectral component in a
current unbalance situation.
MOTOR VOLTAGE SUPERVISION
Default: 50.0%
Range: 0.0 to 100.0%
This setting is used to switch the detection technique from a Power based Coherent
demodulation to a Current based FFT detection method in case the minimum of the
three phase-to-phase voltages falls below the setting configured. This voltage is
expressed as a percentage of the Setpoints > System > Motor > Motor Nameplate
Voltage setting. This setting is hidden for non-voltage order code devices.
PICKUP
Default: -40 dB
Range: -60 to -12 dB
This setting specifies a pickup threshold for this element. The pickup threshold must
normally be set to a level between –54 dB (very likely, a cracked rotor bar) and –50 dB
(probably a broken rotor bar).
DROPOUT DELAY
Range: 0.000to 600.00 s
Default: 0.00
This setting provides the selection for the dropout time delay used to delay the dropout
of the detection of the Broken Rotor Bar condition.
BLOCK
Range: Off, Any operand from the list of FlexLogic operands
Default: Off
The Broken Rotor Bar is blocked, when the selected operand is asserted.
OUTPUT RELAY 2 to 7
Range: Do Not Operate, Operate
Default: Do Not Operate
Any, or all of the output relays 2 to 7 (Depending upon other selections) can be selected
to operate, upon Broken Rotor Bar operation.
EVENTS:
Range: Enabled, Disabled
Default: Enabled
The selection of the Enabled setting enables the events of Broken Rotor Bar function.
TARGETS:
Range: Self-reset, Latched, Disabled
Default: Self-reset
The selection of Self-reset or Latched settings enables the targets of the Broken Rotor
Bar function.
Step: 0.1
Step: 0.1
Step: -1dB
Step: 0.01
MONITORING
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