ESAB ESP-400C Manual De Instrucciones página 321

section 6
6.4.2 iGbt / freewheeling diode (fwd) replacement
caution
caution
A. Insure that input power is removed by two actions such as a disconnect switch and removal of fuses. Tag and lock any
disconnect switch to prevent accidental activation.
B. Remove the top panel to gain access to the modules located in the top rear of the power source.
C. Clean the compartment containing the modules with dry, oil-free compressed air.
D. Unplug the gate drive leads connecting the IGBT Gates to the PWM/Gate Drive PC Board. In order to prevent damage
to the IGBT, install jumper plugs into the IGBT Gate Drive Connector. See Caution below. Jumper plugs are supplied
with each power source.
E. Remove the copper buss plates and bars connected to the IGBT's. Save the M6 hardware connecting the bus structure
to the module terminals. You may need to re-use the hardware. Longer hardware can damage the module by contact-
ing the circuitry directly below the terminals.
F. Remove the M6 hardware mounting the modules to the heat sink. Save the hardware because you may need to re-use
it. Hardware too short can strip the threads in the Aluminum heat sink. Hardware too long can hit the bottom of the
holes causing the modules to have insufficient thermal contact to the heat sink. Hardware too long or too short can
cause module damage due to over heating.
caution
the emitter and the gate of each affected iGbt must be jum-
pered together to prevent electrostatic damage. each power
source is supplied with six jumper plugs that mate to the iGbt
Gate / emitter plug.
electrostatic discharge hazard
electrostatic discharge may damage these components.
• Damage is accumulative and may only appear as shortened compo-
nent life and not as a catastrophic failure.
• Wear a protective ground strap when handling to prevent damage to
PCB components.
• Always place a pc board in a static-free bag when not installed.
removal:
the module gate plugs must be plugged into the pwm/Gate
drive pc board whenever the power source is in operation.
failure to plug them in will result in damage to the module and
possible damage to the torch.
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