Modular coil winding scheme

1
Modular coil winding scheme

• Layout and assembly Fogarty / Williamson
• Field errors Brooks
• Keystoning Chrzanowski/Reiersen
• Recommendation - Nelson

• NCSX WBS-1 Meeting
• July 30, 2003

2
Design Parameters
Baseline design 3-in-hand design
Winding scheme Conventional pancake winding crossover at shell jelly-roll winding, 3 conductors wound in hand
No. of cables 2 x 14 2 x 3 x 9
Size of cables (after keystoning allowance) .665 x .407 .445 x .400
Turn Insulation thickness .054 in. .035 in.
No. of electrical turns 2 x 14 2 x 9
Current per turn 28 49
Current density in Cu 19.7 kA/cm2 18.8 kA/cm2

3
Design Comparison
Baseline design 3-in-hand design
Winding time Wind from middle Wind from end
Insulation application More layers Fewer layers
Keystoning Larger conductor - worse Smaller conductor - better

Cooling adequate adequate
Field errors ( flux in islands) ok ( 1) ok? (2?)
Structure No uncompensated leads Need extra restraint on uncompensated leads
Current density at 1.7 T (max field) 19.7 kA/cm2 (1.3) 18.8 kA/cm2 (1.37)
Current sharing No issue May be an issue for heating, but not field errors

Current per turn 28 kA 49 kA
Coax size in cryostat 3 inch diameter 4.5 in diameter
4
Design Comparison Cost
Baseline design (per J. Chrzanowski, April 03) 3-in-hand design
W I N D I N G Winding facility 1810k Same?
W I N D I N G Materials/supplies 1481k Same?
W I N D I N G Area prep 146k Same?
W I N D I N G Cryo/elect. Test setup 384k Same? (higher current)
W I N D I N G Receive conductor 5k Same?
W I N D I N G Winding 1362k (18400 hrs) 10 less? (- 136k?)
W I N D I N G Structure around leads, extra complexity n.a. ( 50k)?
W I N D I N G Potting cocoon and prep 639k (8640 hrs) Same?
W I N D I N G VPI 597k (8064 hrs) Same?
subtotal 7147k 7061k
Other costs Local coax in cryostat 50k cables 20k for routing? x 1.5 (35k)?
Other costs Bus from D-site (Non-project cost) 1289k (to connect 30 modules?) 10? (129k)?
5
Summary and Recommendation

• Either design is workable
• Baseline is more conventional, has lower current,
  lower field errors, smaller hole in shell for
  leads, smaller coax feed
• 3-in-hand design is easier to wind, should have
  less keystoning and lower current density, but
  field errors may still need investigation
• Project cost should be less for 3-in-hand, but
  program cost may be higher since we will need
  twice as much connecting bus from D-site
• Recommendation
• Use 3-in-hand design for PDR pending confirmation
  of acceptable field errors for actual
  lead/crossover geometry
• Look at multi-cable conductor again (is it really
  that bad?)