Section 8 − Troubleshooting; Removing Cover And Measuring Input Capacitor Voltage - Miller Axcess 450 Owner's Manual

SECTION 8 − TROUBLESHOOTING

8-1. Removing Cover and Measuring Input Capacitor Voltage

Tools Needed:
5/16 in
+ lead to left bus terminal, − lead to right bus terminal
+ lead to left bus terminal, − lead to right bus terminal
OM-211 434 Page 28
Y 900 Volts dc can be present on the capacitor bus and
significant DC voltage can remain on capacitors
after unit is Off. Always check the voltage on both
inverter assemblies as shown to be sure the input
capacitors have discharged before working on unit.
1
2
1
2
Turn Off welding power source, and
disconnect input power.
Remove cover
1 Interconnect Board PC2
2 Voltmeter
Measure the dc voltage across the
+ bus terminal and − bus terminal on
PC2 as shown until voltage drops to
near 0 (zero) volts. Measure input
capacitor voltage on both inverter
assemblies before proceeding.
Proceed with job inside unit. Rein-
stall cover when finished.
802 985 / Ref. 803 419-B