Chapter 6 - Exchange of Thyristors for Size C3
DCS 500 / DCS 600 Service Manual
VI A
6 - 1
Installation of "Disc
Type" thyristor in con-
verters size C3
(900...2000 A)
All DCS 500 and DCS 600 converters sizes A5/C3/C4 are equipped
with disk type thyristors.
The structure of the "disc type" semiconductor component is such
that it requires a certain compression force to operate. The preven-
tion of overheating of the component essentially depends on a well
heat dissipation between the semiconductor and the conducted
heat sink. It is thus important that all joints have good thermal and
electrical conduction.
Required Tools
Special tools or material needed in addition to standard tools for the
exchange of thyristor modules:
-
Torque spanner:
mounting torques and forces for disc
type thyristors see
Table 6-1
electrical connections: 13 Nm (M8)
25 Nm (M10)
50 Nm (M12)
-
Screws are metric type; use appropriate nuts.
-
13 mm nut for thyristor fixing with 20 mm max outer diameter.
-
Tissue paper / solvent (e.g. ethanol).
-
Molikote (MSO
2
).
-
Thermal joint compound:
type
BECHEM-RHUS SU 2
(grease)
Manufacturer:
Carl Bechem GmbH, 58089 Hagen
ABB Service:
GHSN 390 001 P 0001
Note:
For more detailed information about the wiring of
the power part, see publication
Technical Data.
Therefore strict observance of the build in instructions given below
is of utmost importance. Different press clamps are used, depend-
ing on the size of the semiconductor. Make sure that the new com-
ponent can replace the old one in accordance with the spare part
list (see
Appendix A).
Before you start work, disconnect the converter
completly from the power supply then check the
voltage free condition and make sure, everything
is located in an electrically and mechanically safe
condition!
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