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ELECTRONIC TRANSFORMER TAP SWITCH

IP.com Disclosure Number: IPCOM000024571D
Original Publication Date: 1981-Feb-28
Included in the Prior Art Database: 2004-Apr-02
Document File: 2 page(s) / 68K

Publishing Venue

Xerox Disclosure Journal

Abstract

A low-voltage transformer 10 has its main secondary winding 11 connected to a bridge rectifier circuit 12 which comprises four diodes 13, 14, 15 and 16. The output of the bridge rectifier supplies a DC voltage across a load 17. The secondary of the transformer is tapped to provide the main secondary winding 11 and a subsidiary secondary winding 18. Thyristors 19 and 20 are connected between the end of the subsidiary secondary winding 18 and the output points of the bridge circuit 12. The thyristors are arranged to be triggered in response to the value of the input voltage to the transformer.

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XEROX DISCLOSURE JOURNAL

ELECTRONIC TRANSFORMER TAP SWITCH
Proposed J. Verdonk U.S. C1. 330/165 Classification

Int. C1. H03f 1/00

A low-voltage transformer 10 has its main secondary winding 11 connected to a bridge rectifier circuit 12 which comprises four diodes 13, 14, 15 and 16. The output of the bridge rectifier supplies a DC voltage across a load 17. The secondary of the transformer is tapped to provide the main secondary winding 11 and a subsidiary secondary winding 18. Thyristors 19 and 20 are connected between the end of the subsidiary secondary winding 18 and the output points of the bridge circuit 12. The thyristors are arranged to be triggered in response to the value of the input voltage to the transformer.

Both thyristors may be triggered at the same voltage, or they may be triggered at two different voltages. If both thyristors are triggered, diodes 13 and 14 are bypassed by the thyristors so the output voltage across the load 17 includes the contribution of the subsidiary secondary winding 18 as well as that from the main secondary winding 11. If neither thyristor is triggered, the output voltage at the load 17 is that due to the main secondary winding 11 only. If only one thyristor is triggered, successive half-cycles of the output from the bridge circuit 12 will include and exclude the contribution of the subsidiary secondary winding, giving an average voltage at an intermediate level.

By setting the triggering thresholds to respond to appropriat...