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- Engdahl, Göran
(författare)
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Handbook of Electrical Steel
- 2021
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This book contains all information regarding magnetism and magnetic materials that an electrical engineer needs to know to be able to understand and design magnetic devices. The handbook comprises chapters comprising basic electromagnetism, basic quantum mechanics, ferromagnetism, magnetic materials, magnetic material characterization, modeling of magnetic materials, and magnetic design. A comprehensive description of the physical origin of magnetism of materials is given chapter two and a thorough review of the physics behind ferromagnetism is given in chapter three. All chapters are written in a textbook fashion such that they can easily be assimilated separately. The book gathers in an understandable the multidisciplinary topic of magnetism and magnetic materials in way that it can serve as a comprehensive introduction to engineers that considers use of magnetic materials in their designs. The book covers all major modeling techniques of magnetic materials including the well-known Presiach, Jiles-Atherton and lag models. General magnetic design approaches including major and new design tools also are presented. The book also serves as a guideline regarding the choice of feasible materials in specific applications regarding both soft and hard magnetic materials with an inventory of alternatives to electrical steel. Relevant performance criteria then are given such that appropriate materials can be selected. The final chapter offers a list of current electrical steel and magnetic material suppliers.
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| 2. |
- Parekh, Mrunal, 1987-, et al.
(författare)
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Arc Characteristics of Ultra-Fast Opening Switching Contacts in Hybrid Breakers
- 2021
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Ingår i: IEEE Transactions on Power Delivery. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8977 .- 1937-4208. ; 36:5, s. 2872-2880
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Tidskriftsartikel (refereegranskat)abstract
- A mechanical switch can be used instead of a power electronic load commutation switch to reduce losses during normal power flow in standard hybrid DC breakers. The success of current commutation in such hybrid breakers depends on the arc voltage across the contacts of the mechanical switch. The behaviour of rapidly elongated arcs generated during the opening of an ultra-fast mechanical switch in the air is studied here. The voltage-current characteristics of the generated arcs are obtained for contact opening velocities of 6, 11 and 21 m/s. It is found that the arc voltage at a given current and contact separation increases with contact opening velocity. It is shown that stationary, zero-contact-velocity characteristics can not be used to accurately quantify the voltage build-up in fast elongating arcs in hybrid breakers. A best-fitting black-box the equation for the dynamic arc characteristics is presented for the tested velocities. The obtained voltage-current characteristics are used as input to simulate the current commutation process in a 12 kV hybrid DC circuit breaker case-study. Different scenarios of current commutation failure related to the arc voltage build-up are identified. It is shown that these failures scenarios can be avoided by increasing the contact opening velocity.
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