Eaton MP-3000 Instruction Leaflet page 87

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ZSW TRIP
REMOTE
DIF TRIP
PH UNBAL
MP-3000
Table 12.2 Trip Conditions.
Complete help Message
ZERO SPEED SWITCH
INPUT FAILED TO BE
FALSE WITHIN 1/2 OF
LOCKED ROTOR TIME,
OR WAS FALSE AT START
REMOTE TRIP
DIFFERENTIAL TRIP
PHASE UNBALANCE TRIP
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Probable Cause
Discrete input 1 has been
set for zero-speed switch
sensing via setting P6L1.
The 120 Vac zero speed
switch contact input was not
present at the moment of the
start. Or, it did not go away
in one-half of the set locked
rotor or stall time P1L3. This
may be due to a motor
unable to start spinning
when it is energized.
Either or both of discrete
input 1 and/or discrete input
2 are set to indicate remote
trip contact input. The input
configured in this way was
energized with 120 Vac.
Either or both discrete input
1 and/or discrete input 2
are set to indicate remote
trip contact input. The input
configured in this way was
energized with 120 Vac.
• Source voltage unbalance
due to remote fault or
single-phase loading.
• Single phasing of the
motor
IM02602002E
Solution
• Make sure this function has
been intentionally enabled.
• If ZSW trip occurs at the
moment of starting, check
process wiring and contacts
to be sure a 120 Vac signal is
applied to DI 1 when the mo-
tor is stopped.
• Make sure the motor is not
stalled and actually begins to
spin.
• If a ZSW trip occurs after
one-half the locked rotor time
setting, check to be sure the
contact on the motor opens
and the 120 Vac signal goes
away before this time. Usu-
ally, a zero-speed switch
should open when the motor
has reached 5% to 10% of its
normal running speed.
• Use the DI 1 test to confirm
that the relay sees the ex-
pected input voltage.
Determine the source of the
remote contact operation
requesting the trip.
DaNGER: Shut down and
lock out the motor. A differen-
tial relay operation indicates
an electrical fault. Get expert
help in evaluating the condi-
tion of motor and repair needs.
Do not try to restart the motor
without expert evaluation.
After or during repair or re-
placement of the motor, check
the fuses in the starter and
replace blown fuses.
• Check for voltage balance.
• Check the integrity of feeder
connections.
• Check the fuses in the starter.
• Do not attempt to restart
the motor until the cause of
single-phasing is found.
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