摘要:

The Brooks inductor solves a problem, first studied by Maxwell and Gauss, of obtaining the greatest possible inductance with a given piece of wire. A simple procedure, presented graphically and algebraically, facilitates rapid design of air-cored solenoids to required inductance and current loadings. Calculations show that if the winding cross-section is not restricted to rectangles, as assumed hitherto, inductance values may be raised by about 1% above the Brooks limit.

DOI:10.1049/ip-b.1986.0041

出版商:IEE    

年代:1986

数据来源: IET

摘要:

Pole-changing single-winding schemes are applied to self-excited induction generators for the first time and shown to be suitable for wind-driven applications with wide variations in the driving speed. An attempt has also been made to present an analysis of self-excited induction generators by a new approach which is shown to be simple and elegant compared to the earlier methods. Results on a test machine wound with a 4/6-pole combination amply demonstrate the usefulness of pole-changing windings for induction generators. Experimental and predicted performances agree closely, validating the analysis proposed.

DOI:10.1049/ip-b.1986.0042

出版商:IEE    

年代:1986

数据来源: IET

摘要:

Induction billet heating is a well established industrial process for preheating prior to forging, rolling and extrusion. Existing methods of work coil design which are based on the assumption of an infinitely long solenoid and/or the use of a great amount of empirical data are not easily adapted to the design of nonuniform surface power densities. The design of coils to produce such power densities are very empirical at the present time. This paper describes the application of a novel proximity heating technique to design relatively easily, an induction billet heating work coil to give non-uniform surface power densities along a typical industrial workpiece. Theoretical predictions are correlated with practical measurements on typical industrial installations.

DOI:10.1049/ip-b.1986.0043

出版商:IEE    

年代:1986

数据来源: IET

摘要:

In the paper, the short-circuit forces acting on three tubular conductors arranged in an equilateral triangle and constituting a 3-phase system enclosed by a cylindrical aluminium enclosure are examined. The relations for the time functions of the short-circuit forces are developed taking into account the transverse dimensions (diameter) of the conductors. The forces acting on such structures are compared with the forces on structures with filamentary conductors; it results that for usual structures the assumption of filamentary conductors causes a small error in the values of forces; for practical computations the simpler relations that concern forces on filamentary conductors can be used.

DOI:10.1049/ip-b.1986.0044

出版商:IEE    

年代:1986

数据来源: IET