Rockwell Automation WebPak 3000 DC Drives Hardware Reference, Installation and Troubleshooting User Manual
Page 60
5-2
WebPak 3000 DC Drive Hardware Reference
Replacement of a thyristor
on power unit Type 1200 - 2000 A
•
Write protocol about the following procedure
•
Open controller and protection unit by tilting
forwards. Layout of thyristor assembly is
visible now on side wall.
•
Remove bus bars on front heat sink
•
Unscrew the upper cooling air deflector.
Unscrew the hexagon screws for the bus bar
mounting.
•
Unscrew the lower cooling air deflector
•
Loosen the two screws (13 mm) on the clamp
by quarter turns.
(Caution: the center clamp screw 24 mm
must not be turned)
•
Withdraw clamp and heat sink.
•
Clean heat sink from thermo conductive
paste.
•
Coat both sides of the new thyristor with an
thin film of thermo conductive paste /a.
•
Mount the thyristor on the centering pin in the
rear heatsink. Observe correct polarity of
cathode and anode according to layout.
•
Insert clamp in front heatsink and attach to
thyristor with centering pin.
NOTE /b
Tighten the two clamp screws (13 mm)
alternately by one quarter turn until the control
ring under the center clamp nut can be turned
through 360 degree by hand. Keep clearance to
a minimum.
•
Proceed installation in the reverse order of
removal.