Irregular Pilot Arc Starts, Unstable Pilot Arc - Cebora PLASMA PROF 164 HQC Service Manual

CEBORA S.p.A.

3.3.9 - Irregular pilot arc starts, unstable pilot arc.

PLASMA GAS PRESSURE TEST.
Gas pressure in the plasma chamber of the correct torch.
♦ Check operation of the Gas Console and gas circuits, performing if necessary the
tests in par. 3.3.5.
♦ Make sure that pressure and flow rate in the gas supply lines meet the specified
values for the Plasma PROF 164 (see specifications in the Instruction Manual).
HIGH VOLTAGE AT PILOT ARC BOARD (58) INPUT TEST.
Pilot arc board (58) terminals TP3(+) – TP8(-) = approximately +280 Vdc, with rated mains
voltage, stable even with pilot arc lit (max. -10% with pilot arc lit).
♦ Check 3 x 200 Vac, with rated mains voltage, on input terminals of rectifier
bridge (23); if not correct check transformer (27) connections, main voltage
change, contactor (44) and mains voltage.
♦ Check rectifier bridge (23); replace if defective.
♦ Replace the pre-charge (45) and/or control (38) boards.
PILOT ARC VOLTAGE TEST.
Pilot arc board (58), terminals J5(+) – TP7(-) = >+200 Vdc (if pilot arc off) or +150 Vdc
(with pilot arc lit), for a duration of 1 second (maximum pilot arc time) after pressing the
start command.
♦ Go to par. 3.3.6.
♦ Check the wiring between terminals TP7 of pilot arc board (58), inductor (24) and terminal
(53) of the Power Source, and between J5 pilot arc board (58), nozzle resistor (17) and
terminal J6 on torch board (42). If you find loose connections, tighten and replace any
damaged components.
♦ Check the wiring between terminals TP3 and J3 of control box board (5) on module HV18,
extension art. 1179 and terminals (53)(-) of the Power Source and J5(+) on torch board (42).
If you find loose connections, tighten and replace any damaged components.
♦ Check resistor (17). Correct value = 1.3 ohm. Replace if incorrect.
♦ Check the continuity between terminals J5 and J6 on torch board (42). If interrupted, reset the
connection.
♦ Check the wiring between CN2 and CN3 of HF board (2) and TP1 and TP2 of control box
board (5) on module HV18.
♦ Make sure the extension art. 1179 is intact.
3.302.218
Correct?
YES
Correct?
YES
Correct?
YES
NO
NO
NO
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9/8/2006