Filename: long_half_sym_113_85A+3cmZ.ps-- Nathan Rodning Professor of Physics (780) 492-3518 / Fax: (780) 492-0714 http://www.thehungersite.com/
Nate, Further to my email of Friday May 4, please find attached a plot of measurement data, taken at a current of approx. 114A with three predictions, all obtained from model long_half_sym: a) (Predicted Bz obtained at 245A ["Nominal" current for 2.2T] current)*113.85A/245A with nominal coil positions; b) Predicted Bz obtained at 113.85A current with nominal coil positions; c) Predicted Bz obtained at 113.85A current with coil positions shifted by +3cm in Z. d) (Predicted Bz obtained at 113.85A current with coil positions shifted by +3cm in Z)/1.0265; the factor of 1.0265 is to permit comparison between the shape of the predicted and measured curves of Bz versus Z coordinate. The predictions and measurements are shown in the attached file long_half_sym.ps. The absolute error of 2.65% between measurement and prediction could be due to any of a number of factors, e.g. uncertainty in the measured current. long_half_sym.ps is the plot I presented at the E614 meeting on Tuesday morning. I have also attached plot long_half_sym_113_85A+3cmZ.ps; this plot is from the simulation with 113.85A current and coil positions shifted by +3cm in Z. The graph shows predicted Bz, versus Z coordinate, for scans along: a) X=0, Y=0 b) X=-20cm, Y=0 c) X=+20cm, Y=0 d) X=0, Y=+20cm I have spent some time trying to improve the accuracy of the predictions of forces on the conductors. I believe that the results are now reasonably accurate. Below I have tabulated the Net force on all 12 coils (6 coil pairs) in the iron box: a) Current of 245A with nominal coil positions: Fx=0N, Fy=-3850N (approx. 400kg), Fz=0N b) Current of 114A with nominal coil positions: Fx=0N, Fy=-320N (approx. 33kg), Fz=0N c) Current of 114A with coil positions shifted by +3cm: Fx=0N, Fy=-330N (approx. 34kg), Fz=+6200N (630kg) Please note: when the solenoid was energized at full field in New Jersey the solenoid was not in an iron box. Therefore, neglecting magnetic metals near the solenoid, there would have been zero net force on the conductors --- even if there had been a broken strut. Best regards, Mike
Filename: long_half_sym.ps
Filename: long_half_sym_113_85A+3cmZ.ps