ESAB POWERCUT-1500 Bedienungsanleitungen Seite 184

SECTION 4
4.4 IGBT Handling & Replacement
Since IGBT gates are insulated from any other conducting region, care
should be taken to prevent static build up, which could possibly damage
gate oxides. All IGBT modules are shipped from the factory with conduc-
tive foam contacting the gate and emitter sense pins.
Always ground parts touching gate pins during installation. In general,
standard ESD precautions application to FETs should be followed.
Other handling precautions that should also be observed are as follows:
• Use grounded work station with grounded floors and grounded wrist
straps when handling devices.
• Use a 100Ω resistor in series with the gate when performing curve
tracer tests.
• Never install devices into systems with power connected to the
system.
• Use soldering irons with grounded tips when soldering to gate termi-
nals.
When mounting IGBT modules on a heatsink, certain precautions should
be taken to prevent any damage against a sudden torque. If a sudden
torque ("one-sided tightening") is applied at only one mounting terminal the
ceramic insulation plate or silicon chip inside the module may get dam-
aged.
The mounting screws are to be fastened in the order shown in Figure 4-2.
Also, care must be taken to achieve maximum contact (i.e. minimum
contact thermal resistance) for the best heat dissipation.
Application of a thermal pad on the contact surface improves its thermal
conductivity. See Replacement Parts section for the required pad.
A torque wrench should be used. Tighten mounting screws to 28 in-lbs;
wire connecting screws to 19 in-lbs. If torque is too heavy, the device can
damage like the above "one-sided tightening".
Two-Point Mounting Type
Temporary tightening 
Final tightening 
Figure 4-2. Screw Fastening Order
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MAINTENANCE
Four-Point Mounting Type
Temporary tightening 
Final tightening 