ABB DCS 500 Series Service Manual page 48

Chapter 7 - Exchange of Thyristors for Size C4
VI A 7 - 4
Loose
condition
TORQUE INDICATING SPRING
Insulating plate
Correct torque
Figure 7-2 Aluminium spring with welded indicating spring
- Tighten the nuts of the mounting clamp by hand so that the
clamp is in parallel with the contact surface of the heat sinks.
Note: The indicating spring is a very sensitive instrument and
must be handled with care.
- Tighten each nut in turn, half a turn at a time with the help of a
ring spanner until the indicating spring clicks into position "cor-
rect torque" (see Figure 7-2 ). Do not tighten the screws any
further.
Note: The correct torque is indicated by means of the welded in-
dicating spring.
- Perform an OHM test to make sure the thyristor is ok.
- Reconnect the DC / AC – busbars, branch fuses and all other
dismantled parts.
- Perform an OHM test between U1, V1, W1 and C1, D1 to make
sure the power part is ok.
3ADW000093R0601_DCS500B/DCS600_Service Manual_e_f
Heatsink
DCS 500 / DCS 600 Service Manual