Apparatus for identifying faulty diodes in automotive alternators
First Claim
1. In an automotive electrical system containing, an alternator having a polyphase output winding with a full wave bridge rectifier connected thereto, a battery connected across the direct current output terminals of said bridge rectifier to be charged thereby, and a voltage regulator interconnected with said battery and said rectifier output, an electric circuit for identifying a failure therein, comprising:
- (a) first electrical connection with a first terminal of said battery;
(b) a second electrical connection with the other terminal of said battery;
(c) means including a differential comparator, for comparing the difference between two signals input thereto and for establishing an output state therefrom as a function of said compared difference exceeding a predetermined minimum, said comparing means having a reference input and a sensing input, said comparing means and said second electrical connection being electrically referenced to a common electrical potential;
(d) means for providing a photo signal of current flow, said photo signal means being connected between said comparing means output and said first battery connection;
(e) means for coupling both said comparing means reference input and sensing input to said first battery connection, said coupling means providing an AC and DC current path; and
(f) means for additional AC coupling only, of said first battery connection to said comparing means sensing input.
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Accused Products
Abstract
Faulty alternator diodes are identified by detection of a voltage ripple across the terminals of the automotive storage battery. A diode is forward biased whenever the battery has adequate charge to be designated a "good battery", and the forward bias condition is utilized as a reference potential. A voltage divider scales the reference potential, and couples it to the inverting terminal of a comparator. The non-inverting terminal is biased at a predetermined differential from the inverting terminal, and the probe signal is AC coupled to the non-inverting terminal. If a diode is bad, the superposition of the AC with the bias will switch the comparator and energize a light emitting diode.
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Citations
13 Claims
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1. In an automotive electrical system containing, an alternator having a polyphase output winding with a full wave bridge rectifier connected thereto, a battery connected across the direct current output terminals of said bridge rectifier to be charged thereby, and a voltage regulator interconnected with said battery and said rectifier output, an electric circuit for identifying a failure therein, comprising:
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(a) first electrical connection with a first terminal of said battery; (b) a second electrical connection with the other terminal of said battery; (c) means including a differential comparator, for comparing the difference between two signals input thereto and for establishing an output state therefrom as a function of said compared difference exceeding a predetermined minimum, said comparing means having a reference input and a sensing input, said comparing means and said second electrical connection being electrically referenced to a common electrical potential; (d) means for providing a photo signal of current flow, said photo signal means being connected between said comparing means output and said first battery connection; (e) means for coupling both said comparing means reference input and sensing input to said first battery connection, said coupling means providing an AC and DC current path; and (f) means for additional AC coupling only, of said first battery connection to said comparing means sensing input. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification