POWER OUTPUT UNIT AND METHOD FOR DELIVERING CONSTANT FREQUENCY, CONSTANT VOLTAGE AC POWER

• US 3,655,991 A
• Filed: 02/08/1971
• Issued: 04/11/1972
• Est. Priority Date: 02/08/1971
• Status: Expired due to Term

• Current Assignee: Franklin R. Schneider
• Original Assignee: Franklin R. Schneider
• Inventors: Schneider, Franklin R.
• Primary Examiner(s): Schaefer, Robert K.
• Assistant Examiner(s): Smith, William J.
• Application Number:
  US05/113,332
• Time in Patent Office: 428 Days
• Field of Search: 307/1R 290/1,51,50,38R
• US Class Current: 307/10.1
• CPC Class Codes: G05F 1/44 semiconductor devices only
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries
• CPC Class Codes: H02P 2101/45 for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 9/30 using semiconductor devices
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An accessory unit for use with an engine powered vehicle having a conventional electrical system including a battery, voltage regulator and a dynamo which in normal operation supplies DC power to the vehicle electrical system, including switches adapted to isolate the dynamo from the vehicle electrical system, and means for boosting the DC voltage dynamo output and converting it to a constant frequency AC voltage. An outlet receptacle is provided to accept jacks from power tools, appliances or the like having constant frequency AC voltage power requirements. The outlet receptacle voltage is monitored and the dynamo field current is adjusted in response to variations therein to control the dynamo voltage and amperage input to the unit. In another embodiment of the invention, a secondary coil is provided on the transformer along with conventional rectifying means to step down and rectify the increased AC output voltage. Voltage regulator means is provided to sense variations in this low voltage DC secondary output and control the dynamo field current in response to variations therein to maintain a desired dynamo output voltage and amperage. Additionally, the vehicle battery may be charged by an output from the rectified low voltage secondary output of the transformer.

Claims

1. A method of producing constant frequency AC voltage from an engine electrical system including a DC storage battery;

an engine driven dynamo having a field winding terminal and an output terminal which normally delivers low voltage DC power to said electrical system; and

a voltage regulator receiving a power input from said DC storage battery, and having a field terminal connected to the field winding terminal of said dynamo;

said method including the following steps;

a. isolating said dynamo from said electrical system and increasing the DC voltage at the output terminal of the dynamo;

b. applying such increased voltage DC output to the primary coil of an autotransformer;

c. oscillating said increased DC voltage across said primary coil at a substantially constant frequency to produce constant frequency AC voltage;

d. monitoring said constant frequency AC voltage; and

e. controlling the field of said dynamo in response to variations in the voltage level of said constant frequency AC voltage to maintain a substantially constant AC voltage level at said dynamo outlet terminal.

2. The method of claim 1 including the steps of:

a. stepping down and rectifying a portion of said constant frequency AC voltage;

b. monitoring said stepped down DC voltage; and

c. controlling the field of said dynamo in response to variations in said stepped down DC voltage to maintain a desired increased voltage at said dynamo outlet terminal.

3. The method of claim 1 including the steps of:

a. stepping down and rectifying a portion of said constant frequency AC voltage to produce a DC voltage having a value of approximately 14 volts; and

b. maintaining the charge of said DC storage battery of said engine electrical system by applying said stepped down DC voltage thereto.

4. A power output unit adapted to produce constant frequency AC voltage for use with an engine of the type having an electrical system including a dynamo, a DC battery and a voltage regulator, including:

switch means movable to isolate said dynamo from said electrical system and enabling the dynamo DC output voltage to increase;

means for converting the increased DC output voltage from said dynamo to a constant frequency AC voltage;

means sensing the level of said constant frequency AC voltage; and

means for controlling said dynamo DC output voltage to maintain said DC output voltage at a relatively constant level.

5. The power output unit of claim 4 wherein said means for transforming a DC output voltage from said dynamo to a higher, constant frequency AC voltage includes autotransformer means, and means for oscillating said DC output voltage across the primary coil of said autotransformer means.

6. The power output unit of claim 5 wherein said means for oscillating said DC output voltage includes a pair of thyristors connected to the end taps of the autotransformer coil, capacitor means connected between said thyristors, and a constant frequency vibrating means adapted to alternately fire said thyristors.

7. The power output unit of claim 6 wherein said vibrating means includes a solid state oscillating circuit.

8. The power output unit of claim 4 wherein the means for controlling said dynamo DC output voltage is responsive to variations in the constant frequency AC voltage.

9. The power output unit of claim 8 comprising voltage regulator means responsive to variations in the AC voltage and providing a signal output connected to control the dynamo DC output voltage.

10. The power output unit of claim 4 including means for stepping down and rectifying said constant frequency AC voltage, means for monitoring said stepped down DC voltage;

and means for controlling said dynamo DC output voltage responsive to variations in said stepped down DC voltage.

11. The power output unit of claim 10 wherein said means for stepping down and rectifying said constant frequency AC voltage includes an autotransformer having a secondary step down coil and rectifier means connected to said secondary coil and providing a DC output responsive to variations in the level of the constant frequency AC voltage.

12. A power output unit for use with an engine of the type having an electrical system including a DC storage battery;

an engine driven dynamo having a field winding terminal an an output terminal which normally delivers low voltage DC power to said electrical system; and

a voltage regulator receiving a power input from said DC storage battery, and having a field terminal connected to the field winding terminal of said dynamo;

said power output accessory unit being designed to provide a power output for operating power tools, appliances or the like having a constant frequency AC voltage requirement, and comprising;

switch means adapted to disconnect said dynamo from said engine electrical system and allow the DC voltage at the output terminal of said dynamo to increase;

autotransformer means connected to the output of said dynamo;

means oscillating said increased DC dynamo voltage across said autotransformer means and producing a constant frequency AC voltage;

AC outlet receptacle means connected across said autotransformer coil;

means monitoring the output voltage of said autotransformer; and

means controlling the dynamo field current in response to variations in said autotransformer output to maintain a desired voltage level of constant frequency AC voltage at said outlet receptacle.

13. The power output unit of claim 12 wherein said means monitoring the output voltage of said autotransformer and said means controlling said dynamo field current include a voltage regulator.

14. The power output unit of claim 12 including a secondary winding on said autotransformer means adapted to step down the AC voltage, and rectifier means converting the stepped down output of said secondary winding to a DC voltage, and means applying said DC voltage as the input to said voltage regulator.

15. The power output unit of claim 14 comprising means applying an output of said voltage regulator to the field winding of said dynamo to maintain the constant frequency AC voltage at said outlet receptacle at a desired voltage level.

16. The power output unit of claim 12 wherein said switch means includes a momentary portion adapted to automatically disconnect said power output accessory unit from said engine electrical system in response to the failure of said unit and thereby prevent the application of high voltage and/or high amperAge from the dynamo to said power output accessory unit.

17. A power output unit for use with an engine of the type having an electrical system including a DC storage battery;

an engine driven dynamo having a field winding terminal and an output terminal which normally delivers low voltage DC power to said electrical system; and

a voltage regulator receiving a power input from said DC storage battery, and having a field terminal connected to the field winding terminal of said dynamo;

said power output accessory unit being designed to provide a power output for operating power tools, appliances or the like having a constant frequency AC voltage requirement, and comprising;

switch means adapted to disconnect said dynamo from said vehicle electrical system;

autotransformer means connected to the output of said dynamo;

means oscillating said increased DC dynamo voltage across said autotransformer means and producing a constant frequency AC voltage;

AC outlet receptacle means connected across said autotransformer coil;

means monitoring the output voltage of said autotransformer; and

means controlling the dynamo field current in response to variations in said autotransformer output to maintain a desired voltage level of constant frequency AC voltage at said outlet receptacle.

18. The power output unit of claim 17 wherein said means monitoring the output voltage of said autotransformer and said means controlling said dynamo field current include a voltage regulator.

19. The power output unit of claim 17 including a secondary winding on said autotransformer means adapted to step down the AC voltage, and rectifier means converting the stepped down output of said secondary winding to a DC voltage, and means applying said DC voltage as the input to said voltage regulator.

20. The power output unit of claim 19 comprising means applying an output of said voltage regulator to the field winding of said dynamo to maintain the constant frequency AC voltage at said outlet receptacle at a desired voltage level.

21. A power output unit for use with an engine powered vehicle of the type having an electrical system including a DC storage battery;

an engine driven dynamo having a field winding terminal and an output terminal which normally delivers low voltage DC power to the vehicle electrical system; and

a voltage regulator receiving a power input from said DC storage battery, and having a field terminal connected to the field winding terminal of said dynamo;

said power output accessory unit being designed to provide a power output at the vehicle for operating power tools, appliances or the like having a constant frequency, constant voltage, power requirement, and comprising;

switch means adapted to disconnect said dynamo from said vehicle electrical system and allowing the voltage at the output terminal of said dynamo to increase;

autotransformer means including a primary coil connected to said dynamo output terminal;

fixed frequency oscillator means applying said increased DC dynamo voltage across said primary coil to produce a constant frequency AC voltage;

double conductor AC outlet receptacle means connected across said primary coil and adapted to receive power plugs from power tools, appliances or the like having a constant frequency AC voltage requirement;

secondary coil means associated with said autotransformer and adapted to step down the voltage across said primary coil;

rectifier means associated with the output of said secondary coil;

voltage regulation means connected between the rectified, secondary coil output and said dynamo field terminal and adapted to control said dynamo field current in response to variations in the secondary coil output.

22. The power output unit of claim 14 including connector means between said rectified transformer secondary coil output and said battery to maintain said vehicle battery in a charged condition.