3-22 Troubleshooting
7000-TD002A-EN-P – September 2007
FAULT
MESSAGE
FAULT
CODE
DESCRIPTION RECOMMENDED ACTIONS
RNeutral OvrLoad 145
The neutral resistor required for Direct-to-
Drive technology has reached an overload
condition. This is determined from
parameters Neutral Resistor (P680), R
Neutral power Rating (P681). The current
through the neutral resistor is calculated by
measuring the voltage across the resistor
and knowing the resistance. Common Mode
current (P697) displays that current, and R
Neutral OL (P682) shows the overload
accumulator. The resistor is allowed 500%
for 10 seconds every 5 minutes, and P682 is
normalized to fault whenever the value
reaches 1.00.
– Verify the resistor ratings
– Verify that the drive Voltage Feedback
Splitter board is operating properly
– Investigate the possibility of voltage
unbalances on the input or output of the
drive that would create a voltage
differential across the resistor
– Contact the factory for further instructions
– Verify the resistor parameters.
– Investigate the cause of neutral shift
between the input and output filter
capacitors which could be due to severe
line transients or insulation failure.
– Megger the drive if necessary.
Slave1 CurUnbal 124 The level of unbalance in the input current of
the Slave1 Bridge displayed in Slave1 Cur
Unbal (P614) has exceeded the value of the
trip settings (P108). Verify the CTs, burden
resistors and connections on the ACB.
Investigate the incoming source voltage for
unbalance.
Slave2 CurUnbal 125 The level of unbalance in the input voltage
of the Slave 2 Bridge displayed in Slave2
Cur Unbal (P615) has exceeded the value of
the trip settings (P108). Verify the CTs,
burden resistors and connections on the
ACB. Investigate the incoming source
voltage for unbalance.
– Verify that all Current Transformer
connections are connected properly and
that no wires are reversed – Ring-out
wires to verify connections
– Check grounding on CTs
– Ensure that all plugs are firmly
connected in the ACB
– Check that all input voltages are
balanced
– Verify Parameter settings
– Check the burden resistors
– Verify the Input Capacitor values if
installed
– Verify that there are no open sharing
resistors
– Verify all Line Thyristors are firing in
Gating Test Mode
Slave1 Phasing 126 The drive has detected that the phasing in
the Slave1 bridge is incorrect. Verify the
cables are terminated correctly.
Slave2 Phasing 127 The drive has detected that the phasing in
the Slave2 bridge is incorrect. Verify the
cables are terminated correctly.
– Verify cables are terminated correctly
– Verify the feedback wires from the
terminals to the VSB is terminated correctly
– The faults can be masked, and then the
voltages and phasing can be checked
using the test points on the ACB, being
aware that there will be phase
differences between the master and
secondary bridges depending on the
drive configuration. Refer to
Commissioning chapter of the Manual.
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