Chapter 7 - Exchange of Thyristors for Size A7
DCS 500 / DCS 600 Service Manual
VI A
7 - 1
Installation of "Disc
Type" thyristor in con-
verters size A7
(2050...5200 A)
All DCS 500B and DCS 600 converters sizes A5/A6/A7/C3/C4 are
equipped with disk type thyristors. The structure of the "Disc type"
semiconductor component is such that it requires a certain com-
pression force to operate. The prevention 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 for electrical connections:
13 Nm (M8)
25
Nm
(M10)
50
Nm
(M12)
- Screws are metric type; use appropriate nuts.
- 17 mm ring spanner for fuse and busbar connections.
- 24 mm ring spanner for press clamp.
- Tissue paper / solvent (e.g. ethanol).
- Thermal joint compound:
type
BECHEM-RHUS SU 2
(grease)
Manufacturer:
Carl Bechem GmbH, 58089 Hagen
ABB Service:
GHSN 390 001 P 0001
- Disassembly tool:
DCF 1066721 P1
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. Make sure that the new component can re-
place the old one in accordance with the spare part list (
All thyristors are always mounted in the same direction, independ-
ent of current, voltage, number of quadrants (2-Q or 4-Q), left or
right side connection. Semiconductors and heat sinks are to be
handled carefully to avoid scratches and other damage. Avoid
touching the contact surfaces. Do not lift the semiconductor with the
gate wire. Do not lift the semiconductor by touching the current con-
tact surfaces. Do not damage the welding flange or the contact sur-
face.
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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