Dual load control apparatus

• US 4,254,343 A
• Filed: 08/04/1978
• Issued: 03/03/1981
• Est. Priority Date: 08/04/1978
• Status: Expired due to Term

• Current Assignee: Miller J. Vance
• Original Assignee: Miller J. Vance
• Inventors: Miller, J. Vance
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Moose, Richard M.
• Application Number:
  US05/930,895
• Time in Patent Office: 942 Days
• Field of Search: 318/772, 318/779, 318/778, 307/38, 307/41, 307/39, 307/112
• US Class Current: 307/41
• CPC Class Codes: G05D 23/1912 whose output amplitude can take more than two discrete values
• CPC Class Codes: G05D 23/275 with sensing element expanding, contracting, or fusing in response to changes of temperature
• CPC Class Codes: H02P 1/38 by pole-changing

Abstract

Apparatus for controlling parallel connected unequal electrical loads, such as the speeds of a two speed motor, from a two wire branch circuit having one leg load connected through a single pole, single throw switch, utilizing the unbalanced characteristics of the different loads, such as the high and low speed windings of a two speed split phase motor after the start winding circuit is broken, to control multiple solid state static switches coupled through a flip-flop for sequentially controlling the loads.

Claims

1. Electrical control means for controlling unequal electrical loads connected to a source of current, comprising, in combination:

a pair of line conductors, including a first line conductor and a second line conductor for providing a source of electrical current;

load means connected to the first line conductor, including

a first electrical load, and

a second electrical load different from the first electrical load;

pilot switch means for controlling the current flow to the load means, including

a first pilot switch connected to the second conductor of the pair of line conductors and to the first electrical load for providing a flow of current to the first electrical load when turned on, and

a second pilot switch connected to the second conductor of the pair of line conductors and to the second electrical load for providing a flow of current to the second electrical load when turned on;

signal switch means for controlling the pilot switch means, including

a first signal switch connected to the first pilot switch for turning the first pilot switch on and off, and

a second signal switch connected to the second pilot switch for turning the second pilot switch on and off; and

a single pole, single throw switch connected to the first line conductor and to the signal switch means and actuable to turn the first signal switch off and to turn the second signal switch on to turn off the first pilot switch to stop the current flow to the first electrical load and to turn on the second pilot switch to provide current flow to the second electrical load.

2. The apparatus of claim 1 in which the signal switch means includes a flip-flop having a set state and a reset state connected to the first and second signal switches for controlling the first and second signal switches, with the set state of the flip-flop connected to the first and second signal switches for turning the first signal switch on and the second signal switch off and to turn the first pilot switch on and connect the first electrical load to a source of current, and with the reset state of the flip-flop connected to the first and second signal switches for turning the first signal switch off to turn off the first pilot switch to disconnect the first electrical load from the source of current, and for turning the second signal switch on to turn on the second pilot switch to connect the second electrical load to the source of current.

3. The apparatus of claim 2 in which the signal switch means further includes a third signal switch for turning on the flip-flop in response to the flow of current to the load means.

4. The apparatus of claim 3 in which the signal switch means further includes means for turning the flip-flop on in its set state when the third signal switch means is turned on.

5. The apparatus of claim 4 in which the pilot switch means includes a transformer connected to the source of current and having

a first primary winding connected to the first pilot switch means;

a second primary winding connected to the second pilot switch means and wound oppositely from the first primary winding; and

a secondary winding connected to the third signal switch for generating a voltage to turn on the third signal switch in response to an unequal flow of current in the first and second primary windings.

6. The apparatus of claim 5 in which the signal switch means further includes a fourth signal switch for changing the state of the flip-flop from the set state to the reset state to turn off the first signal switch and the first pilot switch, and to turn on the second signal switch and the second pilot switch to disconnect the first electrical load from the source of current and to connect the second electrical load to the source of current in response to the momentary opening and then closing of the single pole, single throw line switch.

7. The apparatus of claim 6 in which the signal switch means further includes a fifth signal switch connected to the first and second signal switches for turning the first and second signal switches on and off.

8. The apparatus of claim 7 in which the signal means further includes a sixth signal switch connected to the transformer and to the fifth signal switch for turning the first and second signal switches off in response to a predetermined current flow to the first or to the second electrical loads.

9. The apparatus of claim 1 in which

the load means includes a third electrical load;

and

the pilot switch means further includes a third pilot switch connected to the third electrical load and to the second conductor of the pair of conductors for providing a current source to the third electrical load, and connected to the signal switch means for turning on and off the third pilot switch.

10. In combination with a split phase electric motor having a start winding, a low speed winding, and a high speed winding, a common conductor connected to one end of each of the windings, and a centrifugal switch having a first pair of normally open contacts, one of which contacts is connected to the other end of the low speed winding, a second pair of normally closed contacts, one of which contacts is connected to the other end of the start winding and the other of which contacts is connected to the other end of the high speed winding, and a third pair of normally closed contacts, one of which contacts is connected to the other contact of the first pair of contacts and the other of which contacts is connected to the other end of the high speed winding and to the other contact of the second pair of contacts, apparatus for operating the motor by providing a source of current to the respective windings of the motor from the other line conductor, comprising, in combination:

a pair of line conductors, including

a first line conductor connected to the common conductor of the electrical motor, and

a second line conductor;

a single pole, single throw line switch connected to the first line conductor having an open and a closed position;

pilot switch means connected to the second line conductor, including

a first pilot switch connected to the other contact of the first pair of normally open contacts for providing current to the other contact of the first pair of contacts and to the one contact of the third pair of contacts, and

a second pilot switch connected to the other end of the high speed winding and to the other contacts of the second and third pairs of contacts;

signal switch means connected to the pilot switch means, including

a first signal switch for turning on and off the first pilot switch,

a second signal switch for turning on and off the second pilot switch,

a third signal switch for turning on the first and second signal switches when the line switch is closed to turn on the first and second pilot switches to provide current for the start winding and the high speed winding for starting the motor, and

flip-flop means for turning on and off the first and second signal switches after the motor has started and in response to the opening and closing of the single pole, single throw line switch.

11. The apparatus of claim 10 in which the pilot switch means further includes a transformer having a pair of oppositely wound primary windings and a secondary winding, and the first pilot switch is connected to the first winding of the pair of primary windings and the second pilot switch is connected to the second winding of the pair of primary windings, and a voltage is generated in the secondary winding after the centrifugal switch is actuated after starting the motor to close the normally open pair of contacts and to open the normally closed pairs of contacts to disconnect the start winding and to connect the low speed winding.

12. The apparatus of claim 11 in which the flip-flop means of the signal switch means includes a flip-flop having a set state and a reset state, a fourth signal switch for turning on the flip-flop in response to the voltage generated in the secondary winding of the transformer, and set means for causing the flip-flop to turn on its set state.

13. The apparatus of claim 12 in which the flip-flop is connected to the first and second signal switches for turning the signal switches on and off in response to the state of the flip-flop, with the set state of the flip-flop connected to the second signal switch to turn the second signal switch off and to allow the first signal switch to remain on, and with the reset state of the flip-flop connected to the first signal switch to turn the first signal switch off and to turn the second signal switch on.

14. The apparatus of claim 13 in which the signal switch means further includes a fifth signal switch connected to the flip-flop for changing the state of the flip-flop from its set state to its reset state in response to the momentary opening and closing of the single pole, single throw line switch to cause the first signal switch to turn off and accordingly for the first pilot switch to turn off to disconnect the low speed winding from the current source, and to cause the second signal switch to turn on and the second pilot switch to turn on to provide current to the high speed winding of the motor to cause the motor to change from low speed to high speed.

15. The apparatus of claim 14 in which the signal switch means further includes a sixth signal switch connected to the third signal switch for turning off the third signal switch in response to a predetermined minimum current flow through the first pilot switch or the second pilot switch.

16. The apparatus of claim 15 in which the signal switch means further includes a first remote switch for turning on the third signal switch in response to the occurrence of a first predetermined event.

17. The apparatus of claim 10 in which the pilot switch means further includes

an auxiliary load, and

a third pilot switch connected to the load for providing current to the auxiliary load and connected to the first signal switch means and to the second signal switch means for turning on the third pilot switch means when either the first or the second signal switches are on.

18. The apparatus of claim 17 in which the pilot switch means further includes a second remote switch connected to the third pilot switch and to the first signal switch for turning the third pilot switch on when the first signal switch is on in response to the happening of a second predetermined event.

19. The apparatus of claim 10 in which the signal circuit means further includes soft start means for turning on the third signal means over a period of time to allow the first and second signal switches to turn on over the same period of time and therefore to connect the motor to the source of current over the period of time.

20. Switching apparatus for providing a signal from two unequal electrical loads, comprising, in combination:

a transformer, including

a first primary winding,

a second primary winding wound oppositely from the first primary winding, and

a secondary winding;

a first electrical load connected to the first primary winding;

a second electrical load different from the first electrical load connected to the second primary winding;

first switch means connected to the first electrical load and to the first primary winding to control the flow of current to the first electrical load;

second switch means connected to the second electrical load and to the second primary winding to control the flow of current to the second electrical load;

third switch means for turning on the first and second switch means to provide current flows through the first and second primary windings and to the first and second electrical loads; and

fourth switch means connected to the secondary winding of the transformer and to the first and second switch means for controlling the first and second switch means in response to a pulse generated in the secondary winding of the transformer by unequal current flow in the first and second primary windings when the third switch means is actuated to provide current flows to the first and second electrical loads.

21. The apparatus of claim 20 in which the first switch means comprises a first triac connected to the first electrical load, to the first primary winding, and to the third and fourth switch means;

and the second switch means comprises a second triac connected to the second electrical load, to the second primary winding, and to the third and fourth switch means.

22. The apparatus of claim 20 in which the fourth switch means includes a flip-flop connected to the secondary winding and having a first stable state connected to the first switch means and a second stable state connected to the second switch means.

23. The apparatus of claim 22 in which the fourth switch means further includes means for changing the flip-flop from its first stable state to its second stable state to turn off the first switch means and to turn on the second switch means.