Alternator test apparatus and method
First Claim
1. A method for testing a variable speed alternator having output winding means, and rectifier means connected to said output winding means for rectifying the alternating voltage produced at said winding means to obtain a direct current output having a variable ripple frequency component at a variable frequency f, said rectifier means including a plurality of diodes, for the failure of one of said diodes, comprising the step of:
- tracking the frequency of and measuring the amplitude of a particular subharmonic of said variable frequency f, said amplitude, when it exceeds a given value, being indicative of a failed diode.
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Abstract
An automobile alternator test apparatus tests for the presence of a failed diode by detecting a frequency component (a subharmonic component) in the alternator output ripple voltage produced by the failed diode. The subharmonic frequency component is detected by a tracking filter that is slaved to the subharmonic frequency of the ripple frequency voltage produced by the failed diode. The output signal of the slaved filter indicates the presence of the failed diode.
194 Citations
7 Claims
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1. A method for testing a variable speed alternator having output winding means, and rectifier means connected to said output winding means for rectifying the alternating voltage produced at said winding means to obtain a direct current output having a variable ripple frequency component at a variable frequency f, said rectifier means including a plurality of diodes, for the failure of one of said diodes, comprising the step of:
tracking the frequency of and measuring the amplitude of a particular subharmonic of said variable frequency f, said amplitude, when it exceeds a given value, being indicative of a failed diode.
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2. Apparatus for testing a variable speed alternator of the type including output winding means, and rectifier means connected to said winding means for rectifying the alternating voltage produced by said winding means to obtain a DC voltage having a variable ripple component at a variable frequency f, the rectifier means including a plurality N of diodes, said apparatus comprising:
means for tracking the frequency of and sensing the amplitude of the component of said DC output voltage at a particular subharmonic of said variable frequency f. - View Dependent Claims (3, 4, 5, 6)
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7. Apparatus for testing an alternator of the type including output winding means, and rectifier means connected to said winding means for rectifying the alternating voltage produced by said winding means to obtain a DC voltage having a ripple component at frequency f, the rectifier means including a plurality N of diodes, said apparatus comprising:
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means for sensing the amplitude of the component of said DC output voltage at a particular subharmonic of f comprising; a tunable first filter tuned to frequency f receptive of said output voltage; a tunable second filter tuned to said subharmonic of f receptive of said output voltage; and means responsive to the output of said first filter for controlling the frequencies to which said first and second filters are tuned for causing said first filter to track said frequency f over a range of f and for concurrently causing said second filter to track said subharmonic of f.
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Specification