POWER TRANSFORMER PRIMARY WINDING FUSE ARRANGEMENT

• US 3,711,747 A
• Filed: 08/10/1971
• Issued: 01/16/1973
• Est. Priority Date: 08/13/1970
• Status: Expired due to Term

• Current Assignee: Hiroshi Sahara, Kiyoshi Yamakawa
• Original Assignee: Hiroshi Sahara, Kiyoshi Yamakawa
• Inventors: Sahara, Hiroshi, Yamakawa, Kiyoshi
• Primary Examiner(s): Goldberg, Gerald
• Application Number:
  US05/170,577
• Time in Patent Office: 525 Days
• Field of Search: 323/48,49,43.5R,6 307/17,83 317/14R,15,4A 336/147,180
• US Class Current: 361/41
• CPC Class Codes: H01F 29/02 with tappings on coil or winding; with provision for rearrangement or interconnection of windings
• CPC Class Codes: H02H 7/04 for transformers
• CPC Class Codes: H02M 5/00 Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases

Abstract

A power supply for use with different AC line voltages, which includes a power transformer having a plurality of separate primary windings and a corresponding plurality of fuses connected thereto. The primary windings are connected to each other in several different ways to change the turns ratio of the power transformer depending upon the value of the voltage supplied thereto. Thus, a predetermined voltage is produced in the secondary winding of the transformer irrespective of the value of the supplied AC line voltage and the current flowing through each of the fuses is held substantially constant, during normal operating conditions, regardless of the manner in which the separate primary windings are connected.

Claims

1. A power supply for use with input voltages of differing magnitude, said power supply comprising;

a power transformer having a secondary winding and a plurality of separate primary windings, said primary windings being interconnected to supply a predetermined operating voltage to an external load;

means for supplying a source of AC voltage to said plurality of primary windings;

means for selectively changing the interconnection of said primary windings, to maintain said predetermined operating voltage when said source of AC voltage is of differing magnitude; and

a plurality of fuse means, a separate one of said fuse means being connected, in series, between each of said separate primary windings and said changing means.

2. A power supply according to claim 1, wherein said separate primary windings each have the same number of turns.

3. A power supply according to claim 2, wherein each of said separate primary windings is provided with at least one intermediate winding tap.

4. A power supply according to claim 1, wherein said changing means includes means for selectively changing the turns ratio of said power transformer to correspond to predetermined magnitudes of the AC voltage supplied to the primary windings, thereby providing a substantially constant voltage at the output of the power supply, irrespective of the magnitude of said AC voltage.

5. A power supply for use with any one of a plurality of different AC input voltages, said power supply comprising;

a power transformer having a secondary winding and at least two separate primary windings each having the same number of turns;

means for supplying a source of AC voltage to said two primary windings;

means for changing the connecting relationship between said two primary windings; and

at least two fuse means respectively connected in series between each of said two primary windings and said changing means.

6. A power supply according to claim 5, wherein each of said two primary windings has a terminal connecting to an intermediate tap on said winding.

7. A power supply according to claim 6, wherein the primary windings are supplied with AC voltage through said changing means.