Snap-On TIG 250 AC-DC, Руководство по обслуживанию

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CEBORA S.p.A.
22
3.3.8 - In resistive load operation, the output voltage is not regular.
WARNING
FOR THESE TESTS DISCONNECT THE CONNECTOR J4 ON HF BOARD (42) TO
PREVENT HIGH FREQUENCY GENERATION.
OPEN CIRCUIT OUTPUT VOLTAGE TEST.
‰
Output terminals - (AB)(-) and + (AC)(+) of power source = voltages according to the table.
Process Voltage Condition
TIG - DC +53 Vdc, fig. 5.2.1a Start button pressed
TIG - AC -28 Vdc, fig. 5.2.1b Start button pressed
Correct?
YES
Correct?
Correct?
NO
♦
Perform the tests in par. 3.3.7.
NOTE
For the following tests use a resistive load that can withstand the maximum current of the power
source. The appropriate values are shown in the table.
Process
Resistive load
resistance
Output current Output voltage Conditions
TIG - DC 0.08 ohm 250 Adc, fig. 5.2.4a +20 Vdc, fig. 5.2.5a Start button pressed
TIG - AC 0.08 ohm 250 Aac, fig. 5.2.4b 20 Vac, fig. 5.2.5b Start button pressed
OUTPUT VOLTAGE TEST ON RESISTIVE LOAD.
‰
Output terminals – (AB)(-) and + (AC)(+) of the power source = values as shown in the table.
NO
YES
♦
Regular operation.
SCR3 ENABLE TEST FOR AC OPERATION.
NOTE
This signal is present only when the welding current is greater than approximately 50 Aac.
With lower currents this signal is absent, and the SCR3 function is performed by just one of the
two similar circuits on the shut-off board (48) (see NOTE in par. 2.3).
‰
Shut-off board (48), connector J2, terminals 1 and 2 = approximately 30 Vac.
YES
NO
♦
Check the wiring between J2 shut-off board (42) and J9 control board (40).
♦
With power source off, temporarily disconnect connector J2 from shut-off board
(40) and check the resistance on terminals 1 and 2 of J2 on shut-off board (48).
Correct values = approximately 300 ohm. If in short-circuit, replace shut-off (48)
and control (40) boards. If >Mohm in all measurements (circuit broken), replace
shut-off board (48).
♦
Replace shut-off (48) and control (40) boards.
3.302.221 15/01/07