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Toroidal Convergence Unit With Unbalanced 4-Pole Winding

IP.com Disclosure Number: IPCOM000047752D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Chase, BD: AUTHOR [+3]

Abstract

U.S. Patent 4,339,736 describes a dynamic convergence unit for an in-line color cathode ray tube in which a toroid is divided into segments provided with windings which result in 4-pole and 6-pole magnetic fields. In a particular implementation using 12 segments, the 4-pole windings were configured as 20 turns per segment for four segments (inductance 68 mH) and 12 turns per segment for 8 segments (inductance 68 mH). This is shown in Fig. 1, which also shows the 6-pole windings in which each field uses six segments with 18 turns per segment (inductance 64 mH). In Fig.1, the dotted lines 6V and 6H represent the two 6-pole fields. The chained lines 4V and 4H represent the two 4-pole fields.

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Toroidal Convergence Unit With Unbalanced 4-Pole Winding

U.S. Patent 4,339,736 describes a dynamic convergence unit for an in-line color cathode ray tube in which a toroid is divided into segments provided with windings which result in 4-pole and 6-pole magnetic fields. In a particular implementation using 12 segments, the 4-pole windings were configured as 20 turns per segment for four segments (inductance 68 mH) and 12 turns per segment for 8 segments (inductance 68 mH). This is shown in Fig. 1, which also shows the 6-pole windings in which each field uses six segments with 18 turns per segment (inductance 64 mH). In Fig.1, the dotted lines 6V and 6H represent the two 6-pole fields. The chained lines 4V and 4H represent the two 4-pole fields. Although the inductances of the coils producing the two 4-pole fields are the same, there are different numbers of turns per segment, resulting in wire- crowding. For optimum results, as shown in Fig. 2, 19 turns per segment can be used in the bottom layer and 20 turns per segment in the top layer. The uniform winding distribution with the same winding pitch allows easy winding on an automatic winder. The set of coils for one 4-pole field will have a higher inductance (186 mH) than the other, but this is permissible from the circuit drive point of view: effectively the two 4-pole fields are the same.

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