Fault indicating circuit for an automotive alternator battery charging system
First Claim
1. A fault indicating circuit for an automotive alternator battery charging system, comprising:
- low voltage detector means for illuminating a display device to provide one visual indication in response to a sensed alternator output signal, related to a rectified alternator output charging signal, having a magnitude below a first predetermined reference voltage magnitude; and
high voltage detector means for illuminating said display device to provide a different visual indication in response to said sensed alternator output signal having a magnitude above a second predetermined reference voltage magnitude greater than said first predetermined reference voltage magnitude, said display device being non-illuminated when said sensed alternator output signal is between said first and second reference voltage magnitudes, whereby said fault indicating circuit utilizes a single display device to provide different distinct visual indications indicative of high and low alternator output modes of failure for an alternator battery charging system,wherein said display device comprises a lamp, andwherein said circuit includes circuitry for serially coupling said lamp and a field coil of said alternator such that said lamp supplies initial excitation current for said field coil when said alternator output charging signal and said sensed alternator output signal are substantially zero.
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Abstract
A fault indicating circuit for an automobile alternator battery charging system is disclosed. The charging system comprises an alternator providing a rectified battery charging signal in response to alternator field coil excitation which is controlled by a voltage regulator that senses battery voltage. The fault indicating circuit comprises a low voltage detector circuit which provides constant DC excitation for an indicator lamp in response to low alternator output voltage and a high voltage detector circuit which provides intermittent excitation for the lamp in response to an excessively high alternator output voltage, the lamp being maintained in a de-energized state in response to the normal alternator output voltage.
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Citations
12 Claims
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1. A fault indicating circuit for an automotive alternator battery charging system, comprising:
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low voltage detector means for illuminating a display device to provide one visual indication in response to a sensed alternator output signal, related to a rectified alternator output charging signal, having a magnitude below a first predetermined reference voltage magnitude; and high voltage detector means for illuminating said display device to provide a different visual indication in response to said sensed alternator output signal having a magnitude above a second predetermined reference voltage magnitude greater than said first predetermined reference voltage magnitude, said display device being non-illuminated when said sensed alternator output signal is between said first and second reference voltage magnitudes, whereby said fault indicating circuit utilizes a single display device to provide different distinct visual indications indicative of high and low alternator output modes of failure for an alternator battery charging system, wherein said display device comprises a lamp, and wherein said circuit includes circuitry for serially coupling said lamp and a field coil of said alternator such that said lamp supplies initial excitation current for said field coil when said alternator output charging signal and said sensed alternator output signal are substantially zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An alternator battery charging system with fault indicating circuit, comprising:
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a battery; alterntor means coupled to the battery for providing a rectified battery chargin signal in accordance with a control signal controlling excitation to an alternator field coil, said field coil normally receiving initial excitation current from said battery when the alternator output is low and subsequently receiving excitation current from an auxiliary rectified output of said alternator instead of said battery; voltage regulator means coupled to said battery and said alternator means for monitoring battery voltage and providing said alternator voltage field coil excitation control signal to maintain said battery voltage at a first voltage level; and fault indicator circuit comprising a lamp coupled in series with said field coil across said battery wherein said initial battery supplied field coil excitation causes illumination of said lamp by passing field current through the lamp, and wherein said fault indicator circuit includes a low voltage detector circuit for illuminating said light in response to a rectified alternator output being below a predetermined level, even if the alternator field coil is open circuited and draws substantially zero current, whereby an indication of low alternator output is provided even if the field coil is open circuited and thereby prevents the drawing of field current through the lamp. - View Dependent Claims (12)
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Specification