Thermal Arc 500 - Page 46

POWERMASTER 500, 500P, 350, 350P
6-4
March 17, 2006
2) REMOTE/LOCAL control:
Each time the REMOTE ON switch is pressed
and released the associated indicator LED
should toggle between ON and OFF. If the LED
is ON this indicates that the power source is
set for remote control.
3) Schedule UP and DOWN controls:
Each time the switch next to the UP arrow is
pressed the PULSE SCHEDULE should increase
by one, until it reaches 24 and rolls back over
to 1. The switch next to the DOWN arrow should
work in a similar way except that the PULSE
SCHEDULE should decrease.
4) Adjust ranges:
To check the output adjust range make sure that
the REMOTE/LOCAL control is set to local, (the
indicator LED should be OFF).
a) GTAW range: 5 - 560 (AMPS display)
b) SMAW range: 5 - 560 (AMPS display)
c) GMAW range: 10 - 44 (VOLTS display)
d) PULSED GMAW range: 0 - 440 (VOLTS
display)
5) CONTACTOR control:
Whenever the CONTACTOR switch is ON the
indicator LED should also be on. Anytime the
CONTACTOR is on, there should be open circuit
voltage present on the output terminals of the
power source. Open circuit voltage should be
approximately 50 - 70 volts for all operating
modes of the power source except GMAW. For
checking open circuit voltage in GMAW mode,
use an external CONTACTOR control.
NOTE:
For load testing the machine or welding in
GMAW mode it will be necessary to use an
external CONTACTOR signal, otherwise the
machine will NOT produce the correct output
voltage.
D. Possible defective main control board.
E. Possible defective IGBT or input rectifier module
(see how to check these parts below).
F. Check internal wiring to control board and
current sensor.
G. Possible defective current sensor.
6. How to check the input rectifier module.
A. See Figure 5-1 and/or Appendix 3 Connection
Diagram.
B. Check all six internal diodes as follows with diode
checker on digital VOM (all should read in the range
of 0.3 to 0.6 volts).
1) Positive meter lead on AC terminal A(1),
negative meter lead on (+) terminal D(4).
2) Positive meter lead on AC terminal B(2),
negative meter lead on (+) terminal D(4).
3) Positive meter lead on AC terminal C(3),
negative meter lead on (+) terminal D(4).
4) Positive meter lead on (–) terminal F(5),
negative meter lead on AC terminal A(1).
5) Positive meter lead on (–) terminal F(5),
negative meter lead on AC terminal B(2).
6) Positive meter lead on (–) terminal F(5),
negative meter lead on AC terminal C(3).