AUTOMOTIVE ELECTRICAL SYSTEM TEST APPARATUS

• US 3,629,704 A
• Filed: 11/24/1967
• Issued: 12/21/1971
• Est. Priority Date: 11/24/1967
• Status: Expired due to Term

• Current Assignee: Carlile R. Stevens
• Original Assignee: Carlile R. Stevens
• Inventors: Stevens, Carlile R.
• Application Number:
  US04/685,456
• Time in Patent Office: 1,488 Days
• US Class Current: 324/98
• 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

Abstract

An automobile alternator and voltage regulator test apparatus which may be connected to the electrical system of a car without altering the existing wiring. The test apparatus analyzes the waveform and magnitude of the ripple voltage superimposed on the alternator output, and also senses the voltage level present at the field terminal of the alternator. In response to the detected ripple characteristics and measured field voltage, the device provides an unambiguous visual indication of which components, if any, are malfunctioning.

Claims

1. A device for testing an alternator having a field terminal and a voltage regulator as interconnected with a battery in an operating vehicle electrical system, said device comprising:

ripple detector means detachably connected across said vehicle electrical system for detecting the presence of a ripple voltage at the terminals of said battery superimposed on the voltage of said battery and for providing an output in response to said detected ripple voltage;

response control means for causing said ripple detector means only to provide an output upon detection of a ripple voltage indicative of a defective alternator diode; and

level-sensing means operable in response to defective indication on said output from said ripple detector means for sensing the voltage level present at the field terminal of said alternator.

2. A device as defined in claim 1 wherein said response control means comprises:

means for reducing the gain of said amplifier.

3. A device as defined in claim 1 wherein said response control means comprises:

means for introducing feedback in said amplifier.

4. A device as defined in claim 1 including level-sensing means operable in response to defective output from said ripple detector means;

first and second indicators;

first means for operating said first indicator when the voltage at said field terminal is at a potential different from that at one terminal of said battery; and

second means for operating said second indicator when the voltage at said field terminal is at the same level as at said one terminal.

5. A device for testing an alternator having a field terminal and a voltage regulator as interconnected with a battery in an operating vehicle electrical system, said device comprising:

ripple detector means detachably connected across said vehicle electrical system for detecting the presence of a ripple voltage at the terminals of said battery superimposed on the voltage of said battery and for providing an output in response to said detected ripple voltage;

said ripple detector means comprises;

an amplifier having a capacitor coupled input;

means for connecting said input to the terminals of said battery;

indicator means cooperating with said amplifier for indicating that a ripple voltage is being amplified;

response control means for causing said ripple detector means only to provide an output upon detection of a ripple voltage indicative of a defective alternator diode;

level-sensing means operable in response to defective output from said ripple detector means comprising;

first and second indicators;

first means for operating said first indicatOr when the voltage at said field terminal is at a potential different from that at one terminal of said battery; and

second means for operating said second indicator when the voltage at said field terminal is at the same level as at said one terminal.

6. A device as defined in claim 5 wherein said first and second indicators comprise first and second lamps.

7. A device as defined in claim 6 wherein said first means comprises means for causing current to flow between said field terminal and said one terminal via said first lamp, and wherein said second means comprises means for causing current to flow between said field terminal and the other terminal of said battery via said second lamp.

8. A device as defined in claim 5 further comprising:

gate means for energizing said first and second means only when no output is being provided by said ripple detector means.

9. A device as defined in claim 5 further comprising:

means for sensing that the voltage across the terminals of said battery is less than a first predetermined value or greater than a second predetermined value.

10. An apparatus for testing an alternator and a voltage regulator as interconnected with a battery in a vehicle electrical system, said device comprising:

an amplifier having an input and an output;

means for capacitively coupling said input to the terminals of said battery whereby a ripple voltage present at said terminals will be amplified by said amplifier;

indicator means, connected to said output, comprising first and second lamps and means for turning ON said first lamp in response to an amplified ripple voltage from said amplifier;

means for introducing feedback in said amplifier to reduce its gain, whereby only said second lamp will be turned ON when a ripple voltage indicative of a defective alternator diode is amplified;

a voltage divider comprising first and second series connected resistors connectable between said battery terminals;

third and fourth lamps, each having one end connected to the junction of said first and second resistors; and

first and second diodes, the anode of said first diode and the cathode of said second diode being connected together and being connectable to the field terminal of said alternator, the cathode of said first diode being connected to the other end of said third lamp, and the anode of said second diode being connected to the other end of said fourth lamp.

11. A device as defined in claim 7 further comprising:

second and third voltage dividers connectable across said battery terminals;

a fifth lamp, and means for turning ON said fifth lamp when the voltage at the junction of said second voltage divider is less than a first predetermined value; and

a sixth lamp, and means for turning ON said sixth lamp when the voltage at the junction of said second voltage divider is greater than a second predetermined value.