An HTS racetrack-type coil without turn-to-turn insulation was characterized by critical current, sudden discharge, and over-current tests with respect to external pressures applied to the straight sections of the coil. The thermal stability of the non-insulated HTS racetrack-type coil was remarkably enhanced with increasing external pressure applied to the straight sections of racetrack-type coil. Furthermore, over-current test results confirmed that the non-insulated HTS racetrack-type coil with increased turn-to-turn thermal contact has the potential to be manufactured into field coils of HTS wind turbine generators with highly enhanced thermal and electrical stabilities.