Recent studies on no-insulation (NI) winding techniques for high temperature superconducting (HTS) coils have demonstrated that an NI coil has a self-protecting feature: a localized quench heat inside the coil can be automatically diverted in the radial direction owing to the absence of turn-to-turn contacts. The obvious benefits of NI may resolve difficulties in the protection of the HTS...
Super High Momentum Spectrometer (SHMS) of Hall C, part of 12 GeV Upgrade at Jefferson Lab, is tested and complete. We will present the measured quench data and the simulated ones of the Q2/3, and Dipole superconducting magnets using the quench code of Vector Fields’ Opera-3D. A multi-channel Tektronix DPO is used to record the signals of the current, voltage of the dump resistor, and other...
Detailed localisation of the quench start in Nb3Sn accelerator magnets by voltage measurements requires a large number of voltage taps, which is less feasible in long prototype coils. Localisation with quench antennas is a proven concept for longitudinal quench localisation in full length accelerator magnets. Quench antennas are also excellent vibration detection tools, and give important...
For the high temperature superconducting (HTS) coils supplied by DC powers, a thermal disturbance may cause local temperature rise and irreversible damage because of constant current. In contrast, when a thermal disturbance occurs, the current flowing in a closed-loop HTS coil operated in persistent current mode (PCM) will decrease correspondingly. In this paper, a closed-loop single-pancake...
The simulation analysis of thermal and electromagnetic behaviors in ReBCO coils after a local normal conduction transition has been performed by many research groups. The numerical analysis, however, were about the behaviors after generating an initial normal spot and the occurrence factor of the initial normal conduction transition has not been sufficiently clarified yet. To clarify the...
It is generally agreed that the development of a self-protective MgB2 magnet may not be achieved because of the slow normal-zone propagation velocity of the MgB2 wires, compared to their low-temperature superconductor counterparts. However, the use of the no-insulation (NI) winding technique can allow the MgB2 magnet to be self-protecting, because the excessive heat and current generated by...
Second generation (2G) high temperature superconducting (HTS) tapes are now capable of carrying very high transport current and promising for a wide range of applications. A large-capacity wind generator prototype has been developed using HTS tapes. The racetrack coils wound with 2G HTS tapes are used in the rotor, whereas the conventional technology is employed in the stator. The reliability...
When a high temperature superconductor (HTS) magnet consisting of a stack of pancake coils is wound, precisely controlling both the outer diameter and number of turns in the coil is difficult, mainly due to manufacturing uncertainty of the HTS tapes. To “arbitrarily” adjust the number of turns in each pancake is often adopted to precisely control the outer diameters, which obviously...
Cea Saclay, in collaboration with the French SMI Sigmaphi, have fabricated a 50 kg solenoid with 2 km of Columbus MgB2 rectangular wire (3*0.7 mm²). The magnet was powered with 100 A at about 10 K and reached 4.2 T on the wire, with an external magnetic field of 3 T. A comparison between the protection and stability theoretical study and experimental results is presented. The quench...
Since 2010 to present, several sub-size magnet assemblies, designed as test beds for impregnated Nb3Sn-based coil technology validation, are tested at the CERN Superconducting Magnet Test Facility (SM18). These Short Model Coils (SMC) and Racetrack Model Coil (RMC) have been used to characterize two types of Rutherford cables foreseen for the coils of the Nb3Sn magnets for the HL-LHC and High...
A Ni-alloy reinforced Bi-2223 conductor (Bi-2223) enables the construction of a compact high field magnet due its high mechanical strength. However, its thermal runaway behavior has not been investigated. The purpose of this paper is to investigate (a) the thermal runaway behavior and (b) the subsequent degradation of a Bi-2223 coil. For this purpose, a five-turn pancake with an artificially...
The 32T all-superconducting user magnet comprised of a REBCO tape pancake-wound dual-coil insert and an LTS multi-coil outsert has been tested at the NHMFL. The magnet protected-quench behavior was simulated using a custom-written Fortran computer code. The simulation results and their sensitivity to the input data are discussed. The effect of insert quench protection system parameters on the...
A REBCO pancake coils using a no-insulation (NI) winding technique is received attention. An NI winding technique greatly enhances the thermal stability of REBCO pancake coils, and it is desired to be applied to high magnetic field NMR/MRI magnet, etc. The high thermal stability of NI REBCO magnets was confirmed in many experiments and numerical simulations, even though any accident due to...