SINGLE PHASE MOTOR STARTING CIRCUIT

• US 3,792,324 A
• Filed: 10/30/1972
• Issued: 02/12/1974
• Est. Priority Date: 10/30/1972
• Status: Expired due to Term

• Current Assignee: Boris Mokrytzki, Julio F. Suarez
• Original Assignee: Boris Mokrytzki, Julio F. Suarez
• Inventors: Suarez, Julio F., Mokrytzki, Boris
• Primary Examiner(s): Rubinson, Gene Z.
• Application Number:
  US05/302,343
• Time in Patent Office: 470 Days
• Field of Search: 318/22R,221R,221D,221E,227
• US Class Current: 318/786
• CPC Class Codes: H02P 1/445 by using additional capacitors switched at start up

Abstract

A SINGLE PHASE MOTOR IS STARTED BY ENERGIZING THE MAIN WINDING AND ALSO ENERGIZING THE STARTING WINDING THROUGH A BIDIRECTIONAL SOLID STATE SWITCH. A condition of the starting winding circuit is sensed such as current or voltage and compared with a reference means and when the sensing signal exceeds the reference means, the conduction through the solid state switch is terminated and remains terminated until the motor is deenergized. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Claims

1. A motor circuit, comprising, in combination, a single phase motor having a main winding and a starting winding, first and second AC input terminals, means energizing said main winding from said input terminals, solid state switch means, a starting winding circuit connecting said starting winding to said solid state switch means and to said input terminals, condition sensing means sensing an electrical condition of said starting winding circuit and having an output, reference means, comparator means comparing the output of said condition sensing means and said reference means, and control means connected to effect conduction of said switch means for starting current through said starting winding circuit upon initial energization of said motor and controlled by said comparator means to terminate conduction of said solid state switch means upon said condition sensing means output exceeding said reference means.

2. A motor circuit as set forth in claim 1, wherein said control means includes means to establish continued cessation of current conduction through said solid state switch means once said condition sensing means output exceeds said reference means until the motor is deenergized.

3. A motor circuit as set forth in claim 1, wherein said control means includes a unidirectional conducting device normally biased into non-conduction by said control means upon initial energization of said motor.

4. A motor circuit as set forth in claim 3, wherein said control means establishes conduction of said unidiRectional conducting device upon said condition sensing means output exceeding said reference means to short-circuit the control of said solid state switch means and hence terminate conduction thereof.

5. A motor circuit as set forth in claim 1, wherein said starting winding circuit includes a starting capacitor and a running capacitor, and said starting winding circuit connects said starting winding in series with said starting capacitor and said solid state switch means.

6. A motor circuit as set forth in claim 5, wherein said starting winding includes an intermediate tap to which said starting capacitor is connected, and means connecting said running capacitor to an end terminal of said starting winding to establish an inductive portion of said starting winding between said starting and running capacitors for surge current protection of said solid state switch means.

7. A motor circuit as set forth in claim 1, wherein said starting winding includes an intermediate terminal and first and second end terminals, and means connecting said condition sensing means to one of said terminals of said starting winding.

8. A motor circuit as set forth in claim 1, wherein said starting winding circuit directly connects said solid state switch means to one of said first and second AC input terminals.

9. A motor circuit as set forth in claim 8, including bypass means for said switch means, and wherein said one of said input terminals is directly connected to said bypass means.

10. A motor circuit as set forth in claim 1, wherein said starting winding includes an intermediate terminal and said condition sensing means is connected to said intermediate terminal.

11. A motor circuit as set forth in claim 1, wherein said control means includes an intermediate tap on said main winding, and biasing signal means connected for energization to said intermediate tap.

12. A motor circuit as set forth in claim 1, including a control electrode on said solid state switch means, said control means including bypass means for said control electrode effective upon bypass of current as controlled by said comparator means to establish cessation of current conduction through said solid state switch means.

13. A motor circuit as set forth in claim 1, wherein said reference means includes a break-down diode having a reverse break-down voltage.

14. A motor circuit as set forth in claim 1, wherein said reference means includes a unidirectional break-down diode having a reverse break-down voltage, and said comparator means connecting said break-down diode to said condition sensing means.

15. A motor circuit as set forth in claim 1, wherein said solid state switch means has a control electrode, said control means including biasing signal means connected to said control electrode to effect conduction of said switch means upon initial energization of said motor, said control means including bypass means for said control electrode effective on bypass of current therethrough to effect cessation of current conduction through said solid state switch means, and means in said bypass means establishing sufficient holding current from said biasing signal means to maintain continued cessation of current conduction through said solid state switch means until the motor is de-energized.

16. A motor circuit as set forth in claim 1, wherein said solid state switch means is a bidirectional conducting device having a control electrode, said control means including a unidirectional conducting device connected as a bypass means to said control electrode, said condition sensing means including unidirectional conducting means conducting only on half cycles of the AC input, said reference means including unidirectional reference means, and said comparator means comparing the unidirectional condition sensing means with the unidirectional reference means to control said unidirectional current conducting device to effect cessation of cUrrent in both directions through said solid state switch means.

17. A motor circuit as set forth in claim 1, including transformer means as a part of said condition sensing means obtaining a sensing voltage by transformer action from said starting winding.

18. A motor circuit as set forth in claim 1, wherein said motor circuit includes a capacitor, and said condition sensing means is connected across said capacitor.

19. A motor circuit as set forth in claim 1, wherein said starting winding circuit includes a starting capacitor, and said condition sensing means is connected across said starting capacitor.