Fabrication and test of force-balanced-coil type air-core superconducting transformer using parallel conductor

A small experimental superconducting air-core transformer was fabricated and tested. It is an autotransformer with a fundamental coil configuration of a kind of helical one. It has a configuration of force-balanced-coil (FBC). The test results show that the transformer works effectively as a power transformer. The obtained output power is about 1 kVA. Because of the absence of iron-core and also because of its force-free configuration, the operation noise of the transformer was very small.