Design and operation of a protection system for transformers with superconducting windings

Power transformers with superconducting windings need a protection system to prevent damage to the low-loss superconducting winding by an abnormally high current. The generally accepted protection technique which uses auxiliary coils has been analysed using a network representation. The current distribution between main and auxiliary coil is expressed in terms of geometrical parameters. Experimental data on current transfer and main coil recovery in a test transformer are presented and a method of obtaining a very low auxiliary coil current is suggested

A superconducting modulator for extremely sensitive voltage measurements across multifilamentary superconducting wires

In this paper we describe a superconducting chopper amplifier used as an instrument to measure the V(I) curve of multifilamentary superconductors. Experimental results are presented

Appreciating what matters:The many dimensions of volunteer value

Volunteering is broadly embedded in our communities. Academics, practitioners, and media often speak to the value volunteers add to society. Most of the time they do so in financial terms calculating cost savings, based on the argument that volunteers can replace paid staff within an organization. However, volunteers are also described as ‘the glue of our country’, suggesting they are valuable beyond the mere financial. One of the main goals in writing this dissertation was to challenge the simplistic financial take on volunteers and to explore, in much nuance, how volunteers create value in different ways (in comparison to paid staff), and thus become influential beyond being a cheaper replacement for paid staff. The chapters in this dissertation all showcase this in different ways and explore how to move away from a cost-saving approach and towards a value-based framework to make more effective and efficient staffing decisions within volunteer-involving organizations

Experimental investigation of the loss characteristics of superconductors for AC power applications

Recent studies confirm the economical feasibility of the application of superconductors in AC power apparatus. The low-loss conductor which has been proposed still only exists in theory. Simple calculations show that the economic criterion described by Ogasawara and Hlásnik is inaccurate because of an oversimplified hysteresis loss formula. A necessary modification shows that stricter demands will have to be made. As production of ultrafine filaments is a big technological problem, final diameter reduction by rolling instead of drawing is proposed. The expected better performance of a rolled composite has been verified experimentally in test coils as well as in transformer geometry. Experimental set-up and results are presented