Gas Flows From The Torch, The Pilot Arc Does Not Light - Cebora 961 Service Manual

CEBORA S.p.A.

3.3.4 - Gas flows from the torch, the pilot arc does not light.

CONTACTOR TLP (32) COMMAND TEST.
Contactors TLP (32) = closed (230 Vac on coil terminals), with start button pressed, for the
pressure over start button lasting time, in normal conditions, or for a brief period in case of
pilot arc doesn't start.
♦ Check the wiring between contactor TLP (32) coil and terminals 2 and 8 of J4 on
control board (4).
♦ With power source off, check the resistance between terminals of contactor TLP
(32) coil. Corrected value = approximately 500 ohm. If 0 ohm (short-circuit),
replace contactor TLP (32) and control board (4).
♦ Check the wired bridge between terminals 1 and 2 of J3 on control board (4). All
auxiliary services, contactors and solenoid valves, are connected under such wired
bridge and fuse F1.
♦ Perform the CONTROL BOARD (4) POWER SUPPLY TEST, par. 3.3.1.
♦ Replace control board (4).
♦ With power source off, check the resistance between terminals of contactor TLP (32) coil.
Corrected value = approximately 500 ohm. If >Mohm (coil interrupted), replace contactor
TLP (32).
POWER SOURCE OPEN CIRCUIT OUTPUT VOLTAGE TEST.
Torch terminal board (31), nozzle and electrode (gnd) terminals = fig. 5.2.1, with start button
pressed. Power source output voltage interrupted for missing pilot arc light on (safety function
against dangerous voltage on the torch (see par. 2.3)).
♦ Check the wiring between J7 of control board (4) and torch cable electrode and
nozzle terminals on terminal board (31).
♦ Check the wiring between rectifier (33) negative terminal, and torch cable
electrode terminal on terminal board (31), and between rectifier (33) positive
terminal, resistor (36) and torch cable nozzle terminal on terminal board (31). If
you find loose connections, tighten them and replace any components with
damaged terminals.
♦ With power source off, check the resistance of resistor (36). Corrected value = 1,4
ohm. If not correct replace resistor (36).
♦ With the power source off and disconnected from the mains, check the efficiency
of the contacts of contactor TLP (32), manually activating it, and make sure that
the resistance on each contact is approximately 0 ohm. If you find burnt contacts
or interference in moving the parts, replace the TLP (32).
♦ With the power source on, check on contactor TLP (32) power terminals voltage =
3 x 190 Vac approximately, both with mains at 230 or 400 Vac..
♦ Check the condition of the windings of transformer (38), especially making sure
that there are no signs of overheating or dents in the winding columns that may
lead to partial short-circuits in the turns. If necessary, replace the transformer (38).
3.302.170
Correct?
YES
Correct?
YES
NO
NO
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06/07/04