Lincoln Electric 718115 Spirit II 275 - Manual (Page 131)

Spirit II User’s Manual Section 6: Maintenance &Troubleshooting
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6-11
Chopper Test Procedure
WARNING: Only qualified maintenance personnel should perform the chopper
test procedure. The system utilizes potentially fatal A.C. and D.C. voltages. All
maintenance should be performed with safety in mind.
Use extreme caution when working near the power conversion module (i.e.,
chopper). The large electrolytic capacitors store large amounts of energy even
after power has been removed from the system. Wait at least five minutes after
turning off power, and then use a voltmeter to verify that the capacitors are fully
discharged before touching the power conversion module.
Capacitor failure can injure and/or cause property damage. If troubleshooting
requires the system to be powered with the enclosure panels removed, remain
clear of the capacitors. Failure of a capacitor can result in a sudden release of
stored energy causing rupture of the capacitor case.
IMPORTANT: Depending upon the system, there are one, two or three chopper
assemblies in the power supply. The following steps must be performed on each
chopper with the other chopper(s) disabled. To disable a chopper, remove the
plug from J1 on the chopper PCB (see drawing on next page).
1. Remove primary power from the Spirit system.
2. Open the impulse start console door and disconnect the black primary wires of the
high frequency transformer from the 120 VAC line filter. Close the impulse start
console door to activate the door interlock switch.
3. Remove the top, left, and right side covers from the power supply to expose the DSP
PCB, input and output terminal blocks and chopper(s).
4. Remove the Electrode, Work and Nozzle leads from the output terminal block, which
is located on the left side of the unit.
5. Ensure the torch head (with a full set of consumables) is properly installed onto the
torch base.
6. Apply primary power to the Spirit system.
7. Release the OFF Button on the Plasma Controller or Manual Gas Console to enable
the system. Press or SELECT the ON Button to energize the system. After the
gases set, prepare to apply a start signal to the unit.