ESAB Precision Plasmarc EPP-450 Manuel D'instructions page 41

section 6
6.3.4 power not on or low voltage
problem
Power source inoperable:
Main power lamp is off.
Low open circuit voltage
6.3.5 fault light illumination
problem
Fault light illuminates at the end of
cut but goes off at the start of the
next.
LED 3 – (amber) Bus Ripple
LED 4 – (amber) High Bus
LED 5 – (amber) Low Bus
possible cause
Missing 3-phase input voltage
Missing 1 of 3-phase input voltage
Fuse F3/F4 blown
Pilot arc Contactor (K4) faulty
Faulty Control PCB1
possible cause
Normal condition caused when ter-
minating the arc by running the torch
off the work o r the arc being a ttached
to a part that falls away.
Imbalance of 3-phase input power
Momentary loss of one phase of
input power
Faulty control PCB1
One or more phases of input voltage
exceed nominal line voltage by more
than 15%.
Faulty control PCB1
One or more shorted diode rectifiers
(D25-D28) on the "Electrode Plate"
One or more phases of input volt-
age are lower than nominal by more
than 15%.
Blown F1 and F2 fuses
Over temp Light comes on.
Imbalanced 3-phase input
power
Momentary loss of one phase of
input power
Faulty Main Contactor (K1)
FAULTY Control PCB1
Restore all 3 phases of input voltage to within
±10% of nominal line.
Restore all 3 phases of input voltage to within
±10% of nominal line.
Replace F3/F4
Replace K4
Replace Control PCB1 (P/N 0558038312)
Reprogram cutting process to
ensure arc is terminated only by
removing the "Contactor On" signal.
Maintain phase voltage imbalance
of less than 5%.
Restore and maintain input power
within ±10% nominal
Replace PCB1 P/N 0558038312
Restore and maintain line voltage
within ±10%
Replace PCB1 P/N 0558038312
Replace shorted diode rectifiers
Restore and maintain within
±10% of nominal
See F1 and F2 in Blown
Fuses Section
See over temp in Fault Light Section
Maintain phase voltage imbalance
of less than 5%
Restore and maintain within
±10% of nominal
Replace K1
Replace PCB1 P/N 0558038312
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