GE Industrial Solutions ASTAT-IBP Plus Solid State Starters - Manual (Page 12)

ASTAT ® -IBP Plus Service Instructions
8 Prices and data subject to change without notice.
SCR Module Replacement (Sizes P, Q,
and R)
This procedure requires the following tools and
materials:
• 1 / 2 " wrench, 3 / 16 " Allen wrench, torque wrench
• Scotchbrite or equivalent abrasive
• Mild solvent to clean mounting surfaces
• Electrolube 2GX or equivalent thermal grease
1. Disconnect the control wiring harness for the SCRs
to be replaced. If necessary, disconnect the wiring
harness of the CTs.
2. Remove the bolt holding the busbar to the line side
of the SCR Module.
3. Remove the bolt holding the CT, spacer, and load-
side busbar to the SCR Module, as shown in Figure
15.
4. Remove the four screws holding the SCR Module to
the mounting plate, as shown in Figure 16.
5. Lift out the SCR Module, as shown in Figure 17.
Retain all parts and hardware for reassembly with
the replacement Module.
6. Remove the MOV by disconnecting it at the spade
connectors. Attach the MOV to the replacement
SCR Module in the same manner.
7. Clean the heat sink surface of the replacement
Module with a fine abrasive, such as Scotchbrite.
Remove all particles from the heat sink surface and
wipe the SCR mounting surface with a mild solvent.
Apply a light coat of thermal grease, such as
Electrolube 2GX to both the SCR and heat sink
surfaces.
8. Place the new SCR Module in the proper position on
the mounting surface. Move the Module back and
forth several times to evenly distribute the grease on
the plate.
9. Secure the SCR Module to the mounting plate with
the screws removed earlier. Tighten the screws to 44
in-lb torque.
10. Reattach the busbars, CT, and spacer to the SCR
Module with the bolts removed earlier. Tighten the
bolts to 150 in-lbs torque.
11. Attach the wiring harness of the new SCR Module to
its mating piece. Attach the wiring harness of the
CTs, if necessary.
Figure 15. Disconnecting the SCR load side..
Figure 16. Removing the SCR mounting screws.
Figure 17. Removing an SCR Module.