Mounting Components On The Heat Sink - ESAB Arc 4000i Service Manual

Mounting components on the heat sink

Thermal paste
Apply thermal conducting paste to the following components before fitting them.
Start by cleaning the heat sink, and then apply a very thin, even layer of thermal paste to
the contact surfaces of the components. The purpose of the paste is to fill out any hollows
in the surfaces of the components and the heat sink. Those parts of the component and the
heat sink that are in true metallic contact may have such contact.
Mount the components as described below. See the spare parts list for the order number for
thermal paste. Use only the paste recommended by us.
Fitting instructions
15Q1, 15Q2 IGBT transistors
Clean the heat sink and apply thermal conducting paste as described above.
Fit the transistor and tighten the screws alternately to a torque of 2.5 Nm,
and then further tighten them to 4.5 Nm. NB: The screws must be tightened
diagonally.
Tighten the screws that connect the IGBT transistors to circuit board 15AP1
to a torque of 4.5 Nm.
CAUTION!
Incorrectly fitted IGBT transistors can cause failure. Do not tighten the screws to
more than 4.5 Nm.
15D1, 15D2 Diode modules
Clean the heat sink and apply thermal conducting paste as described above.
Fit the module and tighten the screws to a torque of 1 Nm, and then further
tighten them to 2.5 Nm.
Tighten the connections to the busbars to 4.5 Nm.
15BR1 Rectifier bridge
Clean the heat sink and apply thermal conducting paste as described above.
Fit the bridge and tighten the screws to a torque of 1 Nm, and then further
tighten them to 4.5 Nm.
Tighten the screws that connect the bridge to circuit board 15AP1 to 4.5 Nm.
15ST2 Thermal overload cutout
Clean the heat sink and apply thermal conducting paste as described above.
Fit the thermal overload cutout.
cp03f2
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S0740 800 191/E080229/P78