Cebora 965, Service Manual, Page: 16 / 24

CEBORA S.p.A.
16
3.3.9 - Transfer arc does not take place or is too weak for cutting.
PILOT ARC OPERATING TEST.
Correct?
‰
Pilot arc lights normally, pilot arc stable.
YES
NO
♦
Go to par. 3.3.8.
TRANSFER ARC SWITCHING TEST.
Correct?
‰
Control board (6), connector J2, terminals 1 and 2 = 0 Vac, reed contact closed, with transfer
arc, thus while cutting (24 Vac reed contact opened, with pilot arc on). This situation remains
constant for as long as cutting continues.
YES
NO
♦
Make sure reed bulb (42) is properly mounted in the corresponding solenoid (43).
♦
With the power source off, make sure that the switch in the reed bulb (42) is
working properly: move a magnet near the bulb and check the resistance between
the terminals 1 and 2 of J2 on control board (6) = 0 ohm (reed contact closed).
Move the magnet away from the bulb; resistance = approximately 5 Kohm (reed
contact open). If incorrect replace reed bulb (42) and solenoid (43).
♦
Replace control board (6).
TRANSFER ARC SOLENOID VALVE EL2 (34) TEST.
Correct?
‰
Solenoid valve EL2 (34) terminals = 230 Vac with transfer arc, for the entire cutting time.
YES
NO
♦
Check wiring between EL2 (34) and terminals 2 and 8 of J7 on control board (6).
♦
With power source off, check resistance between terminals of EL2 (34) = approx.
2500 ohm. If 0 ohm (short-circuit), replace EL2 (34) and control board (6).
♦
Replace control board (6).
♦
With power source off, check the resistance between the terminals of solenoid valve EL2 (34)
= approximately 2500 ohm. If >Mohm (winding broken) replace solenoid valve EL2 (34).
♦
Check connections between torch cable electrode terminal, HF transformer (31) secondary
winding and rectifier (32) negative terminal; between earth cable, output terminal (21) of the
power source, solenoid (43), and rectifier (32) positive terminal. If you find any deteriorated
connections, reset them and replace any damaged components.
♦
Check the condition of the electrode, nozzle, nozzle holder and swirl ring of the torch.
♦
Check the presence of the gas at the inlet fitting (B) and that the pressure and flow rate in the
intake conduit meet the specification values (see Instruction Manual).
♦
Make sure the pressure regulator (E) and pressure gauge (F) are working properly.
♦
Make sure that the gas lines in the power source are not partially clocked, so that the gas
throughput is enough for the pilot arc but not for the transfer arc.
♦
Replace solenoid valve EL2 (34) and/or control board (6).
3.302.173 28/07/04