High temperature superconducting axial field magnetic coupler: realization and test

Abstract

Contactless torque transmission through a large airgap is required in some industrial applications in which hermetic isolation is necessary. This torque transmission usually uses magnetic couplers, whose dimension strongly depends on the airgap flux density. The use of High Temperature Superconducting (HTS) coils to create a strong magnetic field may constitute a solution to reduce the size of the coupler.It is also possible to use this coupler to replace a torque tube in transmitting the torque produced by a HTS motor to its load. This paper presents the detailed construction and tests of an axial field HTS

Fabrication and test of an axial-field HTS rotating machine with integrated magnetic coupling

“…Nevertheless, if only measured U(I) curves are available, it is possible to define an operating current equals to a critical current obtained for a lower critical electric field [14], [22]. By considering a critical electric field of 0.1 V/cm [22].…”

“…The use of HTS materials in magnetic coupling offers the possibility of transmitting high torque through a large air-gap [14][15] while vibrations due to the space harmonics are practically suppressed.…”

Analytical Modeling of an Axial Field Magnetic Coupler With Cylindrical Magnets

“…The main parameters of the coupler [7] are given in Table I. The HTS coils can be supplied by dc current values up to 25 A which result in a high current density in excess of 30 A/mm² at a cooling temperature of 77 K (liquid nitrogen).…”

“…The HTS coils can be supplied by dc current values up to 25 A which result in a high current density in excess of 30 A/mm² at a cooling temperature of 77 K (liquid nitrogen). This coupler has been constructed and successfully tested in [7]. Airgap magnetic fields and torque measurements will serve to validate the analytical model developed here for this coupler.…”

“…For the airgap of 20 mm, the measured and calculated pull-out torques are 19.6 Nm and 16.3 Nm, respectively (16% difference). These discrepancies between the computed and the measured torques may result from the difficulties to perform the tests in a cryogenic environment [7]:…”