Vacon CX, Руководство по обслуживанию

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MAIN CIRCUIT Service Manual M4 - M10
29.12.1999 Page 71
4. Check the base plate from damages, deformations and lacks flatness, as
well as surface roughness.
5. Apply fresh and clean thermal compound on the base plate of the IGBT
with the roller tool. Thickness of layer of the thermal compound is related
to surface quality (heat sink and base plate of the IGBT), like roughness
and flatness. Proper amount of the thermal compound applied on the base
plate is achieved, when the base plate barely gleams through the layer
(thickness 20um). Important in process to apply the thermal compound
onto base plate is to spread even layer of it to cover completely the base
plate of the module.
6. Place the module on the heat sink and line drillings in the heat sink and
openings in the module on same line. Place the fastening screws in the
drillings and pretight the screws down by hands to avoid dropping them
off. Procedure to tighten down the screws will be done in three phases, in
order to avoid risks of damages by mechanical stress in the module.
8.4.5 Tightening order and torque
An order to torque down the fastening screws is illustrated on figure below. In
the case of module with four holes for fastening, always start from a long side
of the module and circle around the module from screw to screw until the
first round is completed. Specification for torque is in chart TORQ.XLS in
section 17.
2.
1.
3.
4.
Tigh te nin g orde r of fa stening screw s
Figure 8.6 Tightening order of fastening screws
Tightening of the screws will be done in three phases to avoid causing
mechanical stress to construction of the IGBT.
1. The first down torquing will be done in order as described above in item
according to torque specifications in chart TORQ.XLS in section 17.3.
Follow the information on column TORQUE #1.
2. For the second tightening, follow the same order. Specification for
torque is in chart TORQ.XLS in section 17. Follow the information on