Cebora 965, Руководство по обслуживанию, Страница: 14 / 24

CEBORA S.p.A.
14
3.3.7 - In open circuit operation, the output voltage is not regular.
WARNING
FOR THE FOLLOWING TESTS DISCONNECT TERMINALS J5 AND J6 ON CONTROL
BOARD (6) TO PREVENT HIGH FREQUENCY FROM BEING GENERATED.
POWER SOURCE OUTPUT VOLTAGE TEST.
Correct?
‰
Output terminal (21) of the power source (+) (workpiece potential) and HF transformer (31)
secondary winding terminal (-) (electrode potential) = +250 Vdc approximately, with start
button pressed, for a duration of approximately two seconds (maximum pilot arc time).
NO
YES
♦
Open circuit output voltage regular.
CONTACTOR TLP (30) COMMAND TEST.
Correct?
‰
Contactor TLP (30) = closed (230 Vac on coil terminals), with start button pressed, for a
duration of approximately two seconds (maximum pilot arc time).
YES
NO
♦
Check the wiring between contactor TLP (30) coil terminals and control board
(6).
♦
With power source off, check the resistance between terminals of contactor TLP
(30) coil. Corrected value = approximately 430 ohm. If 0 ohm (short-circuit),
replace contactor TLP (30) and control board (6).
♦
Perform CONTROL BOARD (6) POWER SUPPLY TEST, par. 3.3.1.
♦
Perform START COMMAND TEST, par. 3.3.3.
♦
Replace control board (6).
♦
With power source off, check the resistance between terminals of contactor TLP (30) coil.
Corrected value = approximately 430 ohm. If >Mohm (circuit interrupted), replace contactor
TLP (30).
♦
Check the wiring between switch (29) and transformer (44) primary winding; and between
transformer (44) secondary winding, contactor TLP (30) and rectifier (32). If you find loose
connections, tighten them and replace any components with damaged terminals.
♦
With the power source off and disconnected from the mains, check the efficiency of the
contacts of contactor TLP (30), 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 (30).
♦
Check the condition of the windings of transformer (44), 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 (44).
♦
With the power source off and disconnected from the mains, check efficiency of rectifier (32).
♦
Check the presence of the power supply three phases at the rectifier (32) input terminals.
♦
Check the mains voltage conditions.
3.302.173 28/07/04