Merlin EPU Support and Drive System Design Review

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Merlin EPU Support and Drive System Design Review

• Steve Marks
• Mark Coleman
• 4/26/06

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Scope of Review- Mechanical System

• Frame Deflection
• Bearings and Mounts
• Deflection
• Load Rating
• Drive Screws Load Rating
• Backing Beams
• Motor Torques

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Other Reviews

• Magnetic structure 2/2/06
• Motor Control System TBD?
• Sector 4 EPBI TBD
• APRP
• Scope
• Installation Readiness

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EPU90 vs. EPU50
EPU50 (old)
EPU90 (new)
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EPU90 vs. EPU50
EPU90 (new)
EPU50 (old)
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What is New?

• 90mm Period (three previous EPUs are50mm)
• Separate mounting of block/keepers
• Avoid correlated motion causing shift dependent
  skew quad
• Modified backing beam
• Bearings closer to load
• Horizontal drive closer to load
• Steel backing beam
• Stiffer Frame
• To accommodate 2.3? vertical load
• Mount encoder directly to backing beams
• Harmonic drive coupling on vertical screws for
  taper adjustment
• Modified gear ratio for horizontal drive

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EPU90
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EPU90
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EPU90
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EPU90
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Vertical Drive

• Drive Screws
• Max. load per screw 17 kN
• Static load rating 107 kN (static),
• Mean load 10 kN
• Dynamic load rating 27 kN (dynamic)
• Linear Roller Bearings
• Moment load 2.7 kN-m
• Rating 7.2 kN-m

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Vertical Drive

• Torque/speed
• Max torque 1.2 N-m
• Max speed 1500 RPM
• Motor rating (with EPU50 motor)
• Cont. Stall Torque 3.9 N-m
• Rated speed 1500 RPM

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Deformation due to Vertical Load
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Vertical Drive

• Drive screw mounting is over constrained
  -affected by deflection of frame and bearing
  mounts.
• EPU90 vs. EPU50 Scaling Comparison
• Vertical columns
• Vertical load F90/F50 2.3
• Frame column stiffness I90/I50 6.5
• Deflection ?90/ ?50 0.35
• Duplex bearing mounts
• Moment M90/M50 1.9
• Stiffness I90/I50 2.0
• Length L90/L50 0.8
• Deflection ?90/ ?50 0.67

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Backing Beam Deflection
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Backing Beam / Horizontal Drive
Deflection Test Setup
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Backing Beam / Horizontal Drive

• Cross Roller Bearings
• Load per roller 1.0 kN
• Bearing load rating 3.9 kN
• Torque/Speed with 5/1 gear ratio (3/1 on EPU50)
• Max. torque 2.1 N-m
• Motor rating (using same motor as EPU50)
• Cont. Stall Torque 3.9 N-m
• Speed limit 900 RPM ? vmax 10 mm/sec (10
  secs. to switch polarization)

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Procurement/Fabrication Plan

• Proceed with procurement of drive screws (long
  lead critical path on schedule)
• Initiate fabrication of backing beams, frame,
  etc.
• Proceed with control system procurement after
  control system discussion/review