Measuring And Discharging Input Capacitor Voltage - Miller Electric Millermatic 350P Aluminum Owner's Manual

7-6. Measuring And Discharging Input Capacitor Voltage

Tools Needed:
5/16 in.
.
A complete Parts List is available at www.MillerWelds.com
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1
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3
Turn Off welding power source and
disconnect input power.
2
Remove case.
1
2
3
Check input capacitors as shown.
Measure the dc voltage across the
positive (+) and negative (−)
terminals until voltage drops to near
0 (zero) volts.
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An example of a typical bleeder re-
sistor is shown on this page.
Proceed with job inside unit.
Reinstall case when finished.
Typical Bleeder
Resistor
25 to 1000 ohm,
5 watt resistor
#16 AWG 1000
volts dc insulation
rating, approx 3 in
(76 mm) leads
Turn Off welding power
source, and disconnect in-
put power.
Significant DC voltage can
remain on capacitors after
unit is Off. Always check ca-
pacitors as shown to be sure
they have discharged before
working on unit.
Input Capacitor C3 Terminals
Input Capacitor C4 Terminals
Voltmeter
Typical Bleeder Resistor
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221 044-A / Ref. 803 550-B
OM-254915 Page 55