Browse Prior Art Database

Self-Gapping, Aligning Inductor Core

IP.com Disclosure Number: IPCOM000035012D
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Miraglia, JA: AUTHOR [+2]

Abstract

Output filter inductors for high current power supplies can be formed by surrounding the output bus with a core of magnetic material. In order to accommodate the DC flux associated with the DC current in the bus, the magnetic flux path must gapped. The conventional approach to providing this gap is to use matching core halves with flat mating surfaces. The core halves are assembled around the core with spacers of non-magnetic material separating them to provide the gap. This approach requires extra pieces (the spacers) and brackets or strapping which must hold the core halves together against the spacers and aligned with each other in the direction along the bus bar. In the structure described here, the core halves are provided with steps or posts on the mating surfaces.

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Self-Gapping, Aligning Inductor Core

Output filter inductors for high current power supplies can be formed by surrounding the output bus with a core of magnetic material. In order to accommodate the DC flux associated with the DC current in the bus, the magnetic flux path must gapped. The conventional approach to providing this gap is to use matching core halves with flat mating surfaces. The core halves are assembled around the core with spacers of non-magnetic material separating them to provide the gap. This approach requires extra pieces (the spacers) and brackets or strapping which must hold the core halves together against the spacers and aligned with each other in the direction along the bus bar. In the structure described here, the core halves are provided with steps or posts on the mating surfaces. When the core halves are assembled, the flux paths through the steps contain no deliberate air gap. However, the cross sectional areas of the steps are chosen so that the steps saturate at low DC currents. At higher currents, the core behaves as if there were a uniform air gap between the core halves. Thus, the required gap is obtained with the cores alone, without extra shims or spacers. Further, some "swinging choke" behavior occurs, with larger inductance at low DC current than at high DC current. This behavior may provide electrical advantages, in addition to the advantage of assembly simplicity. Also, the core mating surfaces are provided with indentation...