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Merlin EPU Support and Drive System Design Review. Steve Marks Mark Coleman 4/26/06. Scope of Review - Mechanical System. Frame – Deflection Bearings and Mounts Deflection Load Rating Drive Screws – Load Rating Backing Beams Motor Torques. Other Reviews. Magnetic structure – 2/2/06
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Merlin EPU Support and Drive System Design Review Steve Marks Mark Coleman 4/26/06
Scope of Review- Mechanical System • Frame – Deflection • Bearings and Mounts • Deflection • Load Rating • Drive Screws – Load Rating • Backing Beams • Motor Torques
Other Reviews • Magnetic structure – 2/2/06 • Motor Control System – TBD? • Sector 4 EPBI – TBD • APRP • Scope • Installation Readiness
EPU90 vs. EPU50 EPU50 (old) EPU90 (new)
EPU90 vs. EPU50 EPU90 (new) EPU50 (old)
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
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
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
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
Backing Beam / Horizontal Drive Deflection Test Setup
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)
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