Troubleshooting & repair, Abnormal output voltage waveform – Lincoln Electric IDEALARC R3R-500 User Manual
Page 72
TROUBLESHOOTING & REPAIR
F-38
F-38
IDEALARC R3R
This is NOT the typical DC output
voltage waveform. One output SCR
is not functioning. Note the “GAP” in
the waveform. One SCR gate is dis-
connected to simulate an open or
non-functioning output SCR. Each
vertical division represents 50 volts
and each horizontal division repre-
sents 5 milliseconds in time. The
machine was loaded with a resis-
tance grid bank.
Note: Scope probes connected at
machine output terminals: (+) probe
to positive terminal, (-) probe to neg-
ative terminal. (R3R 500 machine)
SCOPE SETTINGS
Volts/Div.....................50V/Div.
Horizontal Sweep.....5 ms/Div.
Coupling ............................DC
Trigger .........................Internal
ABNORMAL OUTPUT VOLTAGE WAVEFORM
ONE OUTPUT SCR NOT FUNCTIONING
0 volts
5 ms
50 volts