The use of electric motors or generators for aircraft application requires fewer prime movers and auxiliary equipment than conventional propulsion systems. Thus, the performance in terms of efficiency, reliability is improved. However, the dynamic behaviour of an aircraft required motor which transmit high torque on the propellers. The challenge is to develop an axial-field superconducting motor or a generator with high power density, up to 20 kW/kg
The inductor is composed of several YBCO bulks located inside a YBCO solenoid. The solenoid is fed by a direct current and produce a magnetic field in the axial direction. The diamagnetic behaviour of a superconducting bulk cooled under zero-field is used to obtain a variation of the magnetic flux density in the air-gap.
The YBCO bulks is one of the critical parts of this electrical machine. It is therefore important to know their characteristic. In this paper, we present experimental tests for the YBCO bulk at several temperature in order to evaluate their performance in terms of screening.

Fig. 1 shows the shape of the studied bulk (sector shaped). The main dimensions of the bulk are as follows: the outer radius is 148 mm, the inner radius is 85 mm, the angle of the segment is 36° and the thickness is 10 mm.

 Figure 1: Shape of the superconducting YBCO bulk

Keywords: Superconducting machine, YBCO Bulk, Aircraft Application, Flux Modulation