Semiconductor Installation; Rectifier And Igbt Modules; Secondary Rectifier; Secondary Power Rail - Kemppi Master S 400 Service Manual

Service manual Master S 400 and 500

4.2. Semiconductor installation

It is a must be to use torque screwdriver
sink. See following sections for tightening torques.

4.2.1. Rectifier and IGBT modules

Master S has soldered rectifier and IGBT modules and it is not possible to change them separately. Only
reliable way to replace the module(s) is to change the whole Z001 main circuit card.
The heat sink paste should be spread on to the modules in an even layer by using fingers. Then the card
should be immediately mounted onto the heat sink, this minimizes the possibility of any contamination
(dirt etc.) getting between the components.
The fixing screws for modules are tightened into two stages. First stage ensures proper fastening and
second ensures the heat sink paste is spread evenly and screws are tight enough. Normally stage 1 is
not the final tightening torque for IGBT module. Between the stages it is recommended to have few
minutes break to let the paste spread.
Module
IGBT
Block diode

4.2.2. Secondary rectifier

Secondary diode card is installed similar way as rectifier and IGBT modules but tightening torque is 1,2
and should be made in two stages. Heat sink paste must be used.
Component
Secondary diodes
Power rail to positive Dix connector

4.2.3. Secondary power rail

Special actions must be taken while attached aluminium power rail to secondary heat sink and positive
output connector. Aluminium creates oxide layer and most of it can be removed with wire brush or sand
paper. By adding heat sink paste to these joints between the surfaces water cannot pass there and
corrosion can be avoided.
1. Clean both surfaces carefully
2. Use wire brush or rough sandpaper to remove oxide layer from both aluminium surfaces

Dix does not need to be brushed because it is made of copper
3. Add thin layer of heat sink paste to one of the surfaces
4. Attach power rail to heat sink or to dix connector and tight with proper bolt
18
Kemppi Oy
Version 1.1
while tightening any power components onto the heat
Stage 1 torque
2Nm
2Nm
Stage 1 torque
1,2Nm
2Nm
Stage 2 torque
3Nm
2Nm
Stage 2 torque
1,2Nm
2Nm
5.9.2014