Cebora PLASMA PROF 164 HQC Service Manual page 31

CEBORA S.p.A.
CURRENT MEASUREMENT SIGNALS TEST.
Control board (38), connector J7, terminals 5(+) and 1(-) = approximately +0.7 Vdc ("Power
Source output current measurement" signal); terminals 2(+) and 1(-) = approximately +2 Vdc
("nozzle current measurement" signal) with pilot arc lit.
♦ Check the wiring between J7 control board (38) and J3 settings board (54).
♦ With Power Source off, temporarily disconnect the connector J7 from control
board (38) and check the resistance between the terminals 5-1 and between
terminals 2-1 of J7 on control board (38). Correct value = approximately >1
Mohm, for each measurement point. If incorrect, replace control board (38).
♦ Make sure the circuits to detect the Power Source output current are working
properly, performing if necessary the POWER SOURCE OUTPUT CURRENT
TRANSDUCER POWER SUPPLY TEST and the POWER SOURCE OUTPUT
CURRENT SIGNAL TEST in par. 3.3.8.
♦ Replace the control (38) and/or settings (54) boards.
TRANSFER ARC SWITCHING TEST.
Move the torch with pilot arc lit near the workpiece. Switching in transfer arc takes place,
thus:
- the signal in fig. 5.2.3 (nozzle current) becomes 0 Vdc and remains such for the duration of
cutting (pilot arc current during cutting = 0).
- the signal in fig. 5.2.2 (Power Source output current) changes level. The new current level
depends on the cutting current set, and remains there for the duration of cutting.
- the signal in fig. 5.2.1 (current reference) changes level, from pilot arc current reference to
transfer arc reference, and remains such for the duration of cutting.
- on the Gas Console, the gas circuits switch from Preflow to Cutflow.
♦ Replace control (38) and/or settings (54) and/or pilot arc (58) boards.
♦ Make sure that the gas lines of the Cutflow circuits are not clogged. If necessary, perform the
SOLENOID VALVE TEST in par. 3.3.5..
♦ Check the pressure and flow of the Cutflow gas when the Gas Console activates cutting.
♦ Check the conditions of the torch, and the wear status of the electrode, diffusers and nozzle.
♦ Check the wiring between TP7 pilot arc board (58), inductor (24), terminal (53) on Power
Source, and between J5 pilot arc board (58), nozzle resistor (17), terminal J6 torch board (42).
If you find loose connections, tighten and replace any damaged components.
♦ Check the wiring between TP3 on pilot arc board (58), "gifas" output terminal (+) on the
Power Source front panel, earth cable and workpiece or pantograph terminal. If you find loose
connections, tighten and replace any damaged components.
♦ With Power Source off, temporarily disconnect the cables of the extension art. 1179 from the
Power Source terminals (53) and J5 of torch board (42), and check the isolation between the
disconnected cables and towards earth. This makes it possible to test the isolation of extension
art. 1197, module HV18 and the torch. If you find a short-circuit or low resistance, locate and
replace the defective component.
3.302.218
Correct?
YES
Correct?
YES
NO
NO
31
9/8/2006