Chapter 9 - Preventive Maintainance
VI A
9 - 2
DCS 500 / DCS 600 Service Manual
Internal high cur-
rent connections
in converters
type C4
The thyristors together with the heatsinks are stacked. Every sin-
gle thyristor is connected to the DC+ and DC- busbars via flexible
copper busbars. These busbars consist of 10 layers of preshaped
sheet copper. This construction is able to compensate for small
changes in length caused by temperature rise when current is
flowing. The screw fixings between heatsink and flexible copper
busbar have to withstand different types of mechanical stress.
Therefore each fixing needs to be checked for correct torque.
This check should be done regularly, e.g. annually or together
with all the other work to be done for preventive maintenance.
Actions:
-
Make sure all supply voltages are switched off, most important
the supply for the power part (armature), for the electronic
power part (SDCS-POW-1), for the converter fan and for other
auxiliaries!
-
Open the cabinet’s and module’s door; if needed secure them.
-
Set a latching torque spanner to 25 Nm (18 lb-ft); a 17 mm nut
is needed too.
-
Check the torque of the screws marked within
Figure 9-1 at the
end of this chapter:
-
Apply the torque spanner to the screw and turn right until
the right torque is indicated.
-
Don’t loosen the screws by a left hand turn!
-
Put on a new marking, if appropriate.
Relays and elec-
trical connec-
tions
Relays should be checked for proper function and all connections
should be inspected and checked for tightness. Any signs of cor-
rosion, especially at ground components, must be removed.
3ADW000093R0601_DCS500B/DCS600_Service Manual_e_f
