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 EPU50 (old) EPU90 (new)

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

EPU90

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

Deformation due to Vertical Load

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: F 90 /F 50 = 2.3 Frame column stiffness: I 90 /I 50 = 6.5 Deflection:  90 /  50 = 0.35 –Duplex bearing mounts Moment: M 90 /M 50 = 1.9 Stiffness: I 90 /I 50 = 2.0 Length: L 90 /L 50 = 0.8 Deflection:  90 /  50 = 0.67

Backing Beam Deflection

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  v max = 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