Automobile alternator tester

• US 3,893,029 A
• Filed: 03/25/1974
• Issued: 07/01/1975
• Est. Priority Date: 03/25/1974
• Status: Expired due to Term

• Current Assignee: Jerry A. Leach, Richard R. Vensel
• Original Assignee: Jerry A. Leach, Richard R. Vensel
• Inventors: Vensel, Richard R., Leach, Jerry A.
• Primary Examiner(s): Krawczewicz, Stanley T.
• Assistant Examiner(s): Karlsen, Ernest F.
• Application Number:
  US05/454,125
• Time in Patent Office: 463 Days
• Field of Search: 324/158MG,15,158D,102 322/99
• US Class Current: 324/764.01
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/34 Testing dynamo-electric machines

Abstract

A circuit for testing the operation of an alternator by comparing the DC output level and the AC output level at the battery terminal of the alternator. Only if the DC output is above a predetermined level and the AC output is below a predetermined level does the tester provide a '"'"''"'"''"'"''"'"'satisfactory'"'"''"'"''"'"''"'"' indication.

Claims

1. A test device for testing an automobile three-phase alternator or the like independently of the automobile electrical system and without loading the alternator, the alternator having a ground terminal, a field terminal, and a battery terminal, the test device comprising:

a DC voltage source adapted to be connected to the field terminal and the ground terminal of the alternator to energize the field winding of the alternator, a first circuit means adapted to be connected to the battery terminal and ground terminal of the alternator for producing a first DC signal having a magnitude that varies with the DC output voltage at the battery terminal of the alternator relative to ground, a second circuit means adapted to be connected to the battery terminal and the ground terminal of the alternator for producing a second DC signal having a magnitude that varies with the AC output voltage at the batTery terminal relative to ground, and binary indicator means responsive to the magnitudes of the first and second signals for indicating when both the first signal is above a first predetermined magnitude and the second is simultaneously below a second predetermined magnitude.

2. Apparatus of claim 1 wherein the test device further includes means for driving the alternator.

3. Apparatus of claim 1 wherein the binary indicator means includes a light source, and means for turning on the light source when both the magnitude of the first signal exceeds said first predetermined magnitude and the magnitude of the second signal is below said second predetermined magnitude.

4. Apparatus of claim 3 wherein said means for turning on the light source includes a silicon controlled rectifier having a control electrode, and means responsive to said first and second signals coupled to the control electrode for turning on the silicon controlled rectifier.

5. Apparatus of claim 4 wherein said first circuit means includes an operational amplifier having two input terminals, a DC reference voltage being applied to one terminal, the voltage from the battery terminal of the alternator under test being connected to the other terminal, the output of the operational amplifier being connected to control electrode of the silicon controlled rectifier.

6. Apparatus of claim 5 wherein said second circuit means includes a diode rectifier, a capacitor for coupling the rectifier to the battery terminal of the alternator under test, whereby the output voltage of the rectifier is determined by the magnitude of the alternating current component of the alternator output, and a transistor connecting the control electrode of the silicon controlled rectifier and to the output of the rectifier for biasing off the silicon controlled rectifier in response to the output from said diode rectifier.