Trial manufacture of liquid nitrogen cooling High Temperature Superconductivity Motor

High-c superconductor (HTS) rotating machine with melt-textured Gd-123 bulk pole-field magnets was assembled and tested. The axial gap type motor with neither brush/slip ring nor iron core was composed of a kind of multiple rotor, i.e., a twinned rotor. On each rotor disk, there are eight Gd-123 HTS bulk magnets. The bulk magnets were cooled down with circulating liquid nitrogen supplied inside the rotors. Separately, triple-layered armature copper coils cooled with liquid nitrogen were fixed for pulsed current magnetization for the bulks. Rotation of the twinned rotor provide a better single-phase waveform in 200 rpm compared to in single rotor operation. Magnetic flux density and its distribution on each bulk are stable with averaged decay of 4% for seven hours continuous synchronous operation. The results give a poof on the realization of strong flux collection motor.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

HTS Bulk Pole-Field Magnets Motor With a Multiple Rotor Cooled by Liquid Nitrogen

Matsuzaki

Kimura

Morita

et al. 2007

“…Most HTS motors tested in the US and the EU are of radial-gap type [2], [3]. Some of them employed an iron core inside the Bi-2223 HTS wire-based winding structure [4], [5]. We have successfully studied both design and assembly of a prototype of an HTS axial-gap type synchronous motor for a power propulsion use [6], [7].…”

Section: Introductionmentioning

confidence: 99%

Bi-2223 Field-Poles Without Iron Core for an Axial Type of HTS Propulsion Motor

Sugyo

Kimura

Sano

et al. 2009

We have conducted both electrical and cryomechanical designs of a superconducting propulsion motor based on fieldpoles made of twinned Double-Pancake-Coils (DPC) with Bi-2223 superconducting wire. Neither field-poles nor armature coils have an iron core; that way the magnetic flux increases with increasing applied current in the HTS wire. Special attention has been paid to reducing heat from the coils upon excitation. We have fixed a final design with a low energy loss up to 0.25 W maximum excitation of 1.5 T, corresponding to a current of 200 A at 30 K. In the present study, we have assembled these 8 twinned DPCs into the HTS axial-gap type motor. The dimensions of the motor are 850 mm in diameter for 507 mm in length and the weight is 1044 kg for 100 kW at 230 rpm. The HTS field-pole coils were cooled by thermal conduction by using a circulation of condensed neon with a thermal siphon using a GM cryocooler. We report cryomechanical and technical issues. The successful excitation of the HTS rotor made of 8 twinned DPCs and the rotation test under low frequency are described.

“…Moreover, there are several examples of HTS machines operating at the liquid nitrogen temperature level reported, such as the machines in [4], [5]. The machine in [4] is a radial flux type generator where the BSCCO wires are applied to the magnetic field windings.…”

mentioning

confidence: 99%

Development of an Axial Flux Type PM Synchronous Motor With the Liquid Nitrogen Cooled HTS Armature Windings

Sugimoto

Tsuda

Morishita

et al. 2007

We developed an axial gap permanent magnet type high temperature superconducting synchronous motor (PMHTSSM) at liquid nitrogen temperature. There are two distinctive differences between this motor and the conventional HTS motors. The permanent magnet is applied to the field, iron cores and HTS wires are used as the armature. The motor has eight field poles, and six armature windings. The armature is put between the two fields. The field composes eight permanent magnets which are arranged as a circle. Four poles share three armature coils and there are two coils for every phase. The BSCCO wires, which are applied to armature windings, work at the temperatures of between 66 K and 70 K. The rated output is 400 kW at 250 rpm. It is known that superconducting wires have AC loss if they are operated at alternating magnetic fields. That is why there are few motors developed with superconducting armature windings. Also, there is no report of motors applying HTS wires such as BSCCO wires to armature windings. Furthermore, this motor adopted the revolving field type structure, so the brushes were not needed and the cooling system can be fixed. Also because of the axial-flux type, the structure of the cryostat can be simplified. Index Terms-Axial flux type, BSCCO HTS wire, permanent magnet, permanent magnet HTS synchronous motor. I. INTRODUCTION W E developed a liquid nitrogen cooled axial flux type Permanent Magnet High Temperature Superconducting Synchronous Motor (PMHTSSM). In order to pursuit a high efficiency and small size HTSM and PM synchronous machine, this motor used liquid nitrogen temperature HTS wires as the armature windings instead of copper wires. Since the permanent magnets are used in the field, the armature iron core is necessary to obtain large magnetic flux density.