Chapter 3 - Handling the Semiconductors
DCS 500 / DCS 600 Service Manual
VI A
3 - 1
General Instruction how
to handle the Semicon-
ductors
Thyristor modules, busbars and fuses have to be mounted with the
correct torque using a torque screw driver or torque wrench.
Disc type thyristors in converters size C3 (900...2000 A DC) are
normally mounted using a dial gauge, for repair reasons, they can
be mounted using a torque wrench.
In converters sizes A5 (900...2000 A DC), A6 (1900...3000 A DC),
A7 (2050...5200 A DC) and C4 (2050...5150 A DC) the mounting
force is indicated by an indicating spring welded to the mounting
clamp, which is inside the unit.
Always mark suspected damaged components clearly after remov-
ing them from the circuit, to avoid confusion with "good" compo-
nents.
When removing a damaged semiconductor, write down how and
where it was installed (direction, location, connected gate leads and
with BCT’s the position of the gate connectors).
Check that the new and old component have the same type desig-
nation or that the new component can replace the old one. A semi-
conductor can be replaced by different compatible semiconductor
according to the codes in the manufacturers' table.
Semiconductor components are high-precision products. All unnec-
essary used tools and objects might damage the easily dented and
scratched surfaces of the semiconductors.
1. Keep new semiconductors as long as possible in their original
packages.
2. Use protective gloves if possible.
3. Clean work area and hands frequently.
4. Use good illumination.
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