Storage battery charging system fault indicating circuit

• US 4,041,369 A
• Filed: 12/17/1975
• Issued: 08/09/1977
• Est. Priority Date: 12/17/1975
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Ruff, Donald O., Sheldrake, Leonard J., King, Charles W.
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US05/641,565
• Time in Patent Office: 601 Days
• Field of Search: 322/28, 322/99, 320/48, 320/64, 320/68
• US Class Current: 322/99
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/16 Regulation of the charging current or voltage by variation of field
• CPC Class Codes: Y10S 320/13 Fault detection

Abstract

A circuit for indicating faults in a storage battery charging system of the type including an alternator having a field winding and a rectifier circuit having respective battery charging and alternator field winding energizing output circuit terminals. A differential amplifier circuit, to which is applied normally equal reference sensing potentials which become unbalanced with alternator faults, produces a first fault indicating signal in the event of an alternator malfunction and a transistor having the control electrode connected to the rectifier circuit field winding energizing output circuit terminal produces a second fault indicating signal in the event of a failure of one of the diodes in the rectifier field winding energizing output circuit. These fault indicating signals trigger a transistor conductive to complete an energizing circuit for a fault indicating device.

Claims

1. In a storage battery charging system of the type including a three phase alternator having alternating current output circuitry including three "wye" connected output coils and a field winding;

a rectifier circuit including alternating current input circuitry interconnected with the alternator output circuitry, two separate selected polarity output terminals and a common output terminal of the opposite polarity and electrical circuitry connecting the battery to be charged and the alternator field winding across respective ones of the two separate selected polarity output terminals and the common output terminal of the rectifier circuit, a system fault indicating circuit comprising;

an electrically energizable fault indicating device, a fault indicating device switching transistor having a control electrode and two current carrying electrodes connected in series with said fault indicating device across a source of energizing potential, a transistor having a control electrode connected to the one of said two separate rectifier circuit output terminals to which said alternator field winding is connected and two current carrying electrodes properly electrically poled for forward conduction therethrough;

means for producing a reference potential of a predetermined direct current potential level, means including a transistor having the control electrode thereof connected to the neutral point of said "wye" connected alternator output coils for producing a sensing potential of a direct current potential level directly proportional to the direct current output potential of said rectifier circuit and, in the absence of an alternator fault, substantially equal to said reference potential, a differential amplifier circuit including a pair of transistors having first and second input terminals and first and second output terminals, means for applying said reference potential and said sensing potential each to a respective one of said differential amplifier input terminals;

a first and a second Zener diode;

first circuit means for connecting said first and second output terminals of said differential amplifier circuit, each through a respective one of said first and second Zener diodes, to said control electrode of said fault indicating device switching transistor; and

second circuit means for connecting a selected one of said current carrying electrodes of said transistor to said control electrode of said fault indicating device switching transistor.