ABB
Chapter 8 - Changing Diodes and IGCTs in 7/9 MVA Phase Modules
ACS 6000 Maintenance Manual
3BHS202077 ZAB E01 Rev. C
8-15 (18)
4
Lift the cooler above the diode to be removed with one hand and
extract the diode with the other.
Figure 8-20
Removing the Diode
5
Prepare the components for reassembly.
Check the contact surfaces of the diode, the cooler and the isolator
disk for any dirt. If necessary, clean the contact surfaces with an
appropriate solvent (e. g. alcohol). Using a fluff-free cloth wipe the
surfaces paying attention not to scratch the surfaces.
Note: Do not use any grease or any electrical joint compound.
6
Place the new diode in the stack.
Pay attention to the correct polarity particularly when exchanging
diodes from different suppliers. Always verify the polarity with the
corresponding wiring diagram.
7
Center the diode.
8
Slide the isolator disk back into its place.
Pay attention to properly centering the isolator.
9
Adjust the clamp pressure of the stack.
Insert the the pressure adjusting bolt and tighten it until the clamp
pressure loading gauge is released.
10
Refit the clamp pressure loading gauge in its storage place.
11
Check the blocking/unblocking behaviour of the new diode. Refer to
Chapter 2 - Checking IGCTs and Diodes.
