Tuner Motor Overview for CM2 Page 1
Tuner Motor Overview for CM2 • Background – Bladetuner designed at INFN for ILC type cryomodules. – Original analysis performed at INFN – First tuners built and delivered to Fermilab by INFN – Fermilab “Americanized” the INFN drawings – 50 bladetuners fabricated in U.S. industry – Motor and gearbox design used on most tuners worldwide Page 2
Tuner Motor Overview for CM2 Gearbox (Harmonic Drive) Phytron S.S. Nut Stepper Motor Copper/Beryllium Shaft Page 3
Tuner Motor Overview for CM2 • Potential problems with mechanical connections #1 – Harmonic drive wave generator connection to the motor shaft. – Phytron motor shaft has no previsions for a hard stop connection – Dog point set screws may loose grip on the shaft causing wave generator to slip – Fix – motor shaft was cross-drilled and pointed set screws inserted with cryogenic grade Loctite Page 4
Tuner Motor Overview for CM2 • Potential problems with mechanical connections #1 Page 5
Tuner Motor Overview for CM2 • Potential problems with mechanical connections #2 – Harmonic drive flex gear connection to copper/beryllium shaft – Screws may loosen causing gear to disengage from shaft causing gears to bind – Fix – Internal lock washers added under screws and cryogenic grade Loctite added Page 6
Tuner Motor Overview for CM2 • Potential problems with mechanical connections #2 Page 7
Tuner Motor Overview for CM2 • Testing (Warm) – Each CM2 motor assembly tested on bench setup – Real cavity is used, exact bearing setup, and proper torque (6 N/M) applied – Automatic program ran each motor to 5 million steps to simulate real operating conditions – RF measurements were taken during the process to validate tuning progress Page 8
Tuner Motor Overview for CM2 • Testing (Warm) Cont. – All tests the were successful on the 8 CM2 motors and were subsequently installed on the cavity string – An additional 1 millions steps were performed on each motor as part of the cryomodule assembly procedure – This completed warm testing with 6 million steps at roughly 20% of the lifecycle Page 9
Tuner Motor Overview for CM2 • Testing (Cold) – In parallel with the warm testing, there was an opportunity to perform a cold full lifecycle test in HTS – The goal was to test the motor over a 10 day period to reach 30 million steps (3 million steps per day max.) – The 30 million steps represents about 15-20 years of thermal cycling and cryomodule operation – This part of the test was completed successfully with the tuner/motor still functioning as predicted – Decisions were made to continue the cold test until a failure occurred or the system reached 60 million steps. – Not long after the test resumed the system suffered a failure Page 10
Tuner Motor Overview for CM2 • Testing (Cold) Cont. – An autopsy was performed on the motor assembly and it was determined that the harmonic drive gear stripped and froze the wave generator in the spline gear. – This problem has been documented by other Laboratories Page 11
Tuner Motor Overview for CM2 • CM2 Assembly – There was some apprehensiveness in keeping the CM2 motors installed after the 6 million warm step tests – It was decided to replace the motor/gearbox assembly with all brand new components with the mechanical corrections stated in the previous slides – Light testing was performed on the newly installed assemblies to assure functionality Page 12
Tuner Motor Overview for CM2 • What’s Next? – Mechanical bench testing is currently being done to try and understand the forces and load conditions of the system – FEA analysis of the bladetuner is also under study – As an alternative to the system we are currently using, we are looking at a complete motor drive assembly similar to what DESY is buying for XFEL. The gearbox would replace the harmonic drive assembly with a robust gear system that will be assembled and tested by industry. Page 13
Recommend
More recommend
