From: Wed 5:06 PM Subject: NTX Magnet Status 1/9/02To: SSYU ?SSYU@lbl.gov?, C_Peters ?C_Peters@lbl.gov?, DLVanecek ?DLVanecek@lbl.gov?, DNBeck ?DNBeck@lbl.gov?, Gary Ritchie ?GRitchie@lbl.gov? Meeting 1/9/02 with David Beck, Gary Ritchie, Derek Shuman, and Dave Vanacek present. Some additional topics added by D. Shuman. Any corrections or comments welcome -D. Shuman 1. Coil Winding: A. Backer Block Deflection: A significant amount of coil form backer block deflection relative to the beam was encountered. This is traced to slippage of the bolted joint on the fixed backer block. Shims will be added under the block to limit the defelection and correct the tilt. A design for stiffeners was made and if needed they can be made. The effect of the tilt on final coil dimensions is expected to be very small; accurate measurements of inside coil length will tell. Slightly increased (several mils) conductor spacing between end turns is acceptable. B. Finished Coil Dimensions: It is important that coil dimensions do not exceed the nominal by more than a few mils. Gary will make a go/no go length checking gauge of plastic to allow length measurement without scratching the insulation. Magnet ends should be checked for squareness and straightness in order to optimize the impact cold setting operation at the corners. A plate gauge having a rectangular pocket may be warranted for final dimensional check. C. Coil End Arcing Machine: This machine is being fabricated. Combs to properly space all turns for clamping will be made, as the coils have proved to be very unstable in an unsupported condition. To first order, this should not be very critical, as the ends are arcs and should get bent to the proper shape, even if they are displaced azimuthally from their nominal locations. D. Coil Insulation Check Coils will be checked for insulation breaks after end arc forming but before assembly onto coil forms (lead bending is expected to take place during assembly on coil forms). This test will be a simple electrolyte immersion low voltage leakage current check. A polyethylene liquid container of the type used for hazardous waste disposal (one currently in use in the 58 shops for Dix cleaner) would be suitable for checking coils, even though it is only 27 inches deep (we would like 29"). Perhaps one is readily available from Waste Management Services. A clean 55 gallon drum would also work (and serve as its own ground, if bare metal). A washing tray should be constructed (or procured from the cafeteria) to avoid damaging coil during rinsing. Coils should be suspended with electrolyte line just below the clamped area, if possible. 2. Coil Forms A. Potting test specimens: It was realized last week that the potting test specimens could easily be modified for use as high voltage fatigue test specimens. The FET pulser would be used for high rep rate voltage pulsing over a period of a week or two. This would allow verification of HV resistance of the coil form (through the base to ground) and from conductor to conductor. The specimens will be made with the conductors protruding from both ends of the casting, where they will be wired in alternating polarity. Ground planes will be painted on the front and backside of the casting with conducting paint; the edges shielded with conducting rod where needed. Insulated corona balls can be added to the conductor ends if needed. This test can probably be done before the specimens need to be cut apart to verify epoxy flow behind the wires, as the flow test is only needed to determine if additional grooves are needed on the coil forms. These are features that can be added after they are fabricated. In order to use the potting test specimens as high voltage test specimens they will be milled on the backside to give the .059 thickness of hte coil form. With this thickness we should be able to see the epoxy flow under the conductors without the need to cut them apart. In order to assure the conductors are firmly in the grooves, a fiberglass string tie will be used, similar to what will be used in the actual magnets. Since the conductor are in a plane, the string will not exert force on the middle conductors without a little help. The (well mold released) casting cover will incorporate fingers to depress the string in between the conductors. The resulting grooves in the casting will be filled with epoxy afterward to avoid electrical stress concentration. Dave V. will perform the design for this potting mold, as both David B. and Gary R. are busy with other tasks. B. Coil Form Mandrel The mandrel stock tubes are due in by Friday. They will be sent to LLNL for cold stabilization on Friday if recieved in time. 3. Magnet Laminations: 1. Purchase Order: Purchasing will sole source the lamination fab order to Haig, as recent previous attempts to locate other vendors were fruitless. 2. End Plates: A change to stainless steel is suggested here for the endplates in order to reduce any eddy currents which may have long time constants. Any axial field components will likely have longer time constants, as currents will be in the plane of the lamination (increasing inductance more than resistance) This change will reduce eddy currents by a factor of 4 in the endplate, at a negligible loss of flux return. Cost is approximately 25% higher ($8000 total for 16 endplates). Potting Mold: (no discussion) --------------------------------------------------------------------- Derek Shuman ?DBShuman@lbl.gov? Mechanical Engineer Lawrence Berkeley National Laboratory Derek Shuman Mechanical Engineer ?DBShuman@lbl.gov? Lawrence Berkeley National Laboratory HTML Mail Mailstop 47-112 1 Cyclotron Rd. Fax: 510-486-5392 Berkeley Work: 510-486-4662 CA Conference Software Address 94720 Default Directory Server Additional Information: Last Name Shuman First Name Derek Version 2.1