Battery charger

• US 4,045,717 A
• Filed: 04/13/1976
• Issued: 08/30/1977
• Est. Priority Date: 03/17/1975
• Status: Expired due to Term

• Current Assignee: Yermco, Inc.
• Original Assignee: General Battery Corporation
• Inventors: Schober, William R., Fallon, William H.
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US05/676,475
• Time in Patent Office: 504 Days
• Field of Search: 320/9, 320/22, 320/23, 320/39, 320/40, 320/56, 320/2, 323/45, 323/44 R, 323/9, 321/16, 321/68
• US Class Current: 320/160
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/12 using magnetic devices having controllable degree of saturation, i.e. transductors

Abstract

In a battery charging circuit for charging a battery load characterized by having a substantial effective capacitance, a transformer is connected in a Scott T configuration, the transformer input being adapted for connection to a three phase power line, and the transformer output circuit being in a four phase star configuration for providing a four phase charging circuit. The transformer additionally contains a pair of ferroresonant circuits, each such circuit containing a capacitance selected to cooperate with the capacitance of the battery so as to provide the desired charging characteristic.

Claims

1. A battery charging circuit for charging a battery having an effective load capacitance, said circuit having a charging characteristic within predetermined limits, said characteristic being a functional dependence of charging voltage on amperes per predetermined unit of ampere hours, and said characteristic being substantially independent of the size of said battery, which charging circuit further comprises:

a. a pair of transformers connected in Scott-T configuration;

b. an input connecting means for connecting said transformer to a three phase line;

c. an output connecting means for connection to a first terminal of said battery comprising a separate secondary output winding and rectifier circuit, for each of said transformers;

d. a ferroresonant output circuit means associated with each of said transformers for normally maintaining said transformers in saturation, and for cooperating with said output connecting means to provide said charging characteristic, said means comprising a further transformer secondary winding with only a capacitance connected thereacross, said capacitance predetermined in combination with said effective load capacitance to maintain said charging characteristic within said predetermined limits.

2. A method of providing a battery charging circuit for charging a battery load having an effective capacitance, said charging circuit being characterized by having a charging curve within predetermined limits, comprising:

a. connecting a pair of transformers in a Scott-T configuration, each of said transformers having a primary input winding, and a pair of secondary output windings;

b. connecting said input windings to terminals adapted for connection to a three phase power line;

c. connecting a first one of said secondary output windings from each of said transformers to a rectifier circuit;

d. connecting said rectifier circuit to said battery load terminals, said battery load having said effective capacitance;

e. connecting across a further of said secondary output windings on each of said transformers only a capacitance, which cooperates with said effective capacitance so as to provide a charging curve within said predetermined limits; and

f. removing said load from said battery load terminals.