C1 inspection results

T. Meighan

C1 Lead Block Area

Upper chill plates bowed upwards from side pressure (?)

Top fingers pulled away from winding pack

Pinched/torn insulation

Chill plate deformation and impregnation

Upper chill plates bowed upwards from side pressure (?)

Lack of epoxy under chill plate but glass is wet – may be due to

leak during VPI

Chill plate tabs touch across septum

Glass not completely wetted in lead block

Insulation tear

Tear in insulation

Insulation tear

Insulation tear

Proposed changes

• Only light pressure to be used to assemble lead block while lining up bolt holes. Slotting bolt holes on top plate should be considered to accommodate larger builds. – Avoids pinching insulation– Avoids bowing top chill plates– Avoids pushing top chill plate tabs together– Avoids too much compression on glass leading to resin starved areas

• Undersize rib (narrow the width and perhaps height and add chamfer) in top plate to avoid pinching insulation

• Remove top plate following installation to verify condition inside lead block

• Care continues to be needed when sealing conductors penetrating the bag mold

• Long fingers on top chill plates already removed via ECN• Improved technique for bending chill plate tabs following C1 should

pay dividends on subsequent coils

Proposed Repair of C1 Lead Box Area

• Rotate C1 on end so that box is facing upward.

• Machine box lid in some areas to take pressure off pinched areas. (Dry fit lid)

• Paint epoxy on torn glass and resin starved areas. Insulation Resistance = (15K Meg @ 7.5KV)

• Do a wet lay up of glass and epoxy. (CTD 540 Rm Temperature Cure)

More photos