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Browse Prior Art Database

Automatic Selection of Line Voltage Tap for a Power Supply

IP.com Disclosure Number: IPCOM000060203D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Bauman, K: AUTHOR [+2]

Abstract

A four-pin appliance coupler is used in connection with voltage- standardized wall plugs to provide an automatic selection of line voltage tap for a power supply. Switching power supplies can be designed to run on both the 100- to 120-volt and 200- to 240-volt AC types of utility lines by configuring the input rectifiers and filter capacitors in either a doubler or full-wave bridge configuration. The selection may be accomplished by using either a switch or a jumper. Transformer and ferroresonant supplies accommodate the dual-voltage input possibility by changing taps on the transformer. In any of the cases it is desirable to be able to easily change from one configuration to the other. The usual solution is a customer accessible switch, but this often results in an incorrect selection of input voltage.

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Automatic Selection of Line Voltage Tap for a Power Supply

A four-pin appliance coupler is used in connection with voltage- standardized wall plugs to provide an automatic selection of line voltage tap for a power supply. Switching power supplies can be designed to run on both the 100- to 120-volt and 200- to 240-volt AC types of utility lines by configuring the input rectifiers and filter capacitors in either a doubler or full-wave bridge configuration. The selection may be accomplished by using either a switch or a jumper. Transformer and ferroresonant supplies accommodate the dual-voltage input possibility by changing taps on the transformer. In any of the cases it is desirable to be able to easily change from one configuration to the other. The usual solution is a customer accessible switch, but this often results in an incorrect selection of input voltage. A four-pin appliance coupler wired as shown in Fig. 1 (for switching supplies) or Fig. 2 (for transformer-type supplies) accomplishes the selection as a function of the wiring of the line cord. Line side connectors (wall outlets) are available which are unique for a particular voltage level. Therefore, line cords are provided which are wired so that selection of a line cord which is compatible with the wall outlet automatically makes the proper machine voltage connection. Examples are shown in Figs. 3 and 4. In Fig. 3, conductors 10, 12 connect 120 V AC across terminal 1, 2 of coupler 14. Thus, when 14 is...