RECYCLE PREVENTION CONTROL CIRCUIT

• US 3,716,756 A
• Filed: 03/03/1972
• Issued: 02/13/1973
• Est. Priority Date: 03/03/1972
• Status: Expired due to Term

• Current Assignee: John N. Runge, Kenneth R. Krusling
• Original Assignee: John N. Runge, Kenneth R. Krusling
• Inventors: Runge, John N., Krusling, Kenneth R.
• Primary Examiner(s): Trammell, James D.
• Application Number:
  US05/231,668
• Time in Patent Office: 347 Days
• Field of Search: 317/13A,36TD,141S 318/484
• US Class Current: 361/22
• CPC Class Codes: H02H 11/006 in case of too high or too low voltage
• CPC Class Codes: H02H 7/0816 concerning the starting sequence, e.g. limiting the number of starts per time unit, monitoring speed during starting
• CPC Class Codes: H02H 7/09 against over-voltage; against reduction of voltage; against phase interruption

Abstract

Timed control for preventing recycling of an electric motor drive compressor after a power interruption. It includes a solidstate pre-set time delay circuit which, upon timing out, closes normally open contacts to permit energization of the motor driven compressor. A latching circuit automatically locks in the power supply to the motor driven compressor and deenergizes the time delay circuit until power is interrupted.

Claims

1. A control circuit for preventing restarting of electrical apparatus for a preset time after a power interruption comprising:

a. first normally open electrical contacts effective when closed to connect said electrical apparatus to a power supply;

b. second normally open contacts effective when closed to connect said electrical apparatus to said power supply, said second normally open contacts being connected in parallel to said first normally open contacts;

c. first electrical means for closing said first normally open contacts;

d. preset time delay circuit means connected to said power supply and effective upon timing out to energize said first electrical means whereby to close said first normally open contacts after said preset time delay;

e. second electrical means connected to said power supply for closing said second normally open contacts only after said first normally open contacts have been closed; and

f. means for opening said first normally open contacts to reset said time delay circuit as said second normally open contacts are closed.

2. The control circuit claimed in claim 1 wherein said means for opening said first normally open contacts and resetting said time delay circuit is responsive to said second electrical means.

3. The control circuit claimed in claim 2 wherein said means for opening said first normally open contacts and resetting said time delay circuit includes normally closed contacts arranged to be opened by said second electrical means.

4. The control circuit claimed in claim 1 including a thermostatically controlled switch connected between said power supply and said first and second normally open contacts.

5. The control circuit claimed in claim 1 wherein said first and second electrical means are of relative sizes such that the current effective to energize said first electrical means will not energize said second electrical means.

6. The control circuit claimed in claim 1 wherein said time delay circuit includes an scr connected in series with said first electrical means, triggering of said scr being effective to energize said first electrical means.

7. The control circuit claimed in claim 1 wherein said time delay circuit includes a timing resistor, a unijunction, and a timing capacitor connected in series, the output pulse of said uNijunction being effective to trigger said scr.