US3763377A - Random cycle load switch - Google Patents

Random cycle load switch Download PDF

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Publication number
US3763377A
US3763377A US00242573A US3763377DA US3763377A US 3763377 A US3763377 A US 3763377A US 00242573 A US00242573 A US 00242573A US 3763377D A US3763377D A US 3763377DA US 3763377 A US3763377 A US 3763377A
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triac
current
voltage source
load
cathode
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US00242573A
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A Weston
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
    • H03K17/72—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region
    • H03K17/722—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region with galvanic isolation between the control circuit and the output circuit
    • H03K17/723—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region with galvanic isolation between the control circuit and the output circuit using transformer coupling

Definitions

  • ABSTRACT Current to a primary load is sensed and utilized in order to simultaneously complete a circuit which includes a secondary load and a triac.
  • a current transformer has a primary winding in series with the primary load and a secondary winding coupled to the cathode and gate electrodes of the triac, so that a current to the primary load will cause a gate current sufficient to switch the triac from a non-conducting state to a conducting state.
  • This invention relates to apparatus for supplying current to one load during such time as current is being supplied to some other load. More particularly, this invention relates to an electrical circuit wherein application of current to a primary load, such as a refrigerator motor or other appliance, will cause the simultaneous application of current to a secondary load, such as a light located externally of the refrigerator.
  • a primary load such as a refrigerator motor or other appliance
  • the light may be automatically turned on and off simultaneously with the random on and off conditions of the refrigerator motor.
  • One practical application of such apparatus is to turn a light or lights on and off from time to time in unoccupied homes or buildings to create the impression of occupancy to would-be intruders.
  • the apparatus of this invention comprises electrical circuitry in which a secondary load, such as a lamp, will receive current when and only when a primary load, suchas a refrigerator motor, receives current.
  • a secondary load such as a lamp
  • a primary load such as a refrigerator motor
  • Motors in refrigerators and freezers operate automatically from time to time and for varying lengths of time in order to maintain the device at a preset temperature. Such operation, as by use of thermal switches, is a builtin feature of modern refrigerators and freezers. Other appliances or devices may also have such random on and off operating characteristics of course.
  • a light located externally of a refrigerator and the refrigerator motor are both connected to a voltage source.
  • the main terminals of a triac are electrically connected in series with the light.
  • a current transformer has its primary winding connected in series with the voltage source and the refrigerator motor.
  • the secondary winding of the transformer has one end connected to the cathode of the triac and its other end connected through a resistor to the gate of the triac.
  • a refrigerator motor 10, or primary load is connected by leads l2 and 14 to a soure of voltage 16, such as an ordinary l 10 volt A.C. household outlet.
  • the lead 12 is connected to the primary winding 18 of a step down current transformer 20 and to motor 10.
  • Leads 24, 26, and 28 connect a lamp 30, or secondary load, and a triac 32 in series with the'voltage source 16.
  • the triac 32 has an anode 34 and a cathode 36 which are its main terminals, and a gate electrode 38.
  • the secondary winding 39 of the transformer 20 has its one end 40 connected by the lead 42 to the cathode 36 of the triac.
  • the other end 44 of winding 39 is connected by a lead 46 through a resistor 48 to the gate 38.
  • the refrigerator is designed to be maintaned at preset temperatures, and to that end it is constructed so that its motor will be automatically turned on and off as needed. Typically, random on and off conditions occur.
  • the motor 10 When the motor 10 is turned on, for example, by operation of a thermal switch, it receives current from the voltage source 16. The current to the motor passes through the primary winding 18, which results in a current in the secondary winding 39 of the transformer 20. Since the winding 39 is connected to the cathode 36 and the gate 38 of the triac, the current from the winding 39 is applied to the gate 38. the values of a circuit components are selected so that such a gate current will cause the triac to switch from its non-conducting state to its conducting state. When the triac 32 conducts, the electrical circuit which includes the voltage source 16, the triac 32, and the lamp 30 is completed or closed, causing the lamp 30 to be simultaneously lighted.
  • Apparatus for supplying current to a secondary load simultaneously with current flow from a voltage source to a primary load comprising a secondary load connected to the voltage source and a triac, a current transformer having a winding connected to the voltage source and the primary load and having a winding with one end connected to the cathode of said triac and its other end connected through a resistor to the gate of said triac, whereby current flow from the voltage source to the primary load will initiate a flow of current to said gate electrode and cuase said triac to become conducting, thereby completing the circuit which includes the voltage source, the triac, and the secondary load.
  • Apparatus for operating a source of illumination in conjunction with the operation of an electrical appliance which is connected to a voltage source comprising a source of illumination electrically connected in a circuit with a voltage source and a triac having anode, cathode, and gate electrodes, a current transformer having a primary winding connected to the voltage source and the appliance, said transformer having a secondary winding having one end connected to said cathode and its other end connected through a resistor to said gate electrode, whereby current to the appliance causes a gate current sufficient to cause the triac to switch to a conducting state to complete the electrical circuit which includes said source of illumination.
  • Apparatus for turning a lamp on and off simultaneously with the random on and off operation of a refrigerator motor which is connected to a voltage source comprising a lamp located externally of the refrigerator, a triac having anode, cathode and gate electrodes, said lamp being connected to said voltage source and to said anode, a current transformer having a primary winding connected to the voltage source and the refrigerator motor, said transformer having a secondary winding having one end connected to said cathode and its other end connected through a resistor to said gate electrode, whereby said triac is in a nonconducting state when the refrigerator motor is off and is in a conducting state when the refrigerator motor is

Abstract

Current to a primary load is sensed and utilized in order to simultaneously complete a circuit which includes a secondary load and a triac. A current transformer has a primary winding in series with the primary load and a secondary winding coupled to the cathode and gate electrodes of the triac, so that a current to the primary load will cause a gate current sufficient to switch the triac from a non-conducting state to a conducting state.

Description

Wired States Patent [1 1 Weston 1 Oct. 2, 1973 RANDOM CYCLE LOAD SWITCH 22 Filed: Apr. 10,1972
211 Appl.No.:242,573
Primary Examiner-Herman .l. Hohauser Attorney-Thomas P. Jenkins et al.
[57] ABSTRACT Current to a primary load is sensed and utilized in order to simultaneously complete a circuit which includes a secondary load and a triac. A current transformer has a primary winding in series with the primary load and a secondary winding coupled to the cathode and gate electrodes of the triac, so that a current to the primary load will cause a gate current sufficient to switch the triac from a non-conducting state to a conducting state.
3 Claims, 1 Drawing Figure [52] 11.8. C1. 307/140, 307/17, 307/252 B [51] Int. Cl. H0lh 33/59 [58] Field of Search ..307/11, 17, 140,
[56] References Cited UNITED STATES PATENTS 3,527,957 9/1970 Eck 307/140 l6 L y RANDOM CYCLE LOAD SWITCH BACKGROUND OF THE INVENTION This invention relates to apparatus for supplying current to one load during such time as current is being supplied to some other load. More particularly, this invention relates to an electrical circuit wherein application of current to a primary load, such as a refrigerator motor or other appliance, will cause the simultaneous application of current to a secondary load, such as a light located externally of the refrigerator.
Using the example of a refrigerator motor and an external light, the light may be automatically turned on and off simultaneously with the random on and off conditions of the refrigerator motor. One practical application of such apparatus is to turn a light or lights on and off from time to time in unoccupied homes or buildings to create the impression of occupancy to would-be intruders.
Looting and vandalizing homes and other buildings while the occupants are away is an all to frequent occurrence. Locks and burglar alarms undoubtedly help in the prevention of such intrusions. At night, a lighted house may also deter a potential burglar. However, this ruse can become quite apparent, especially where the occupants are frequently absent and the house is periodically observed. While it is unlikely that any system is foolproof, the deterrant effect on intruders is be lieved to be increased by changes in lighting from time to time. This strengthens the impression that someone is present in the home, and random rather than periodic lighting changes are more realistic for this purpose.
SUMMARY OF THE INVENTION The apparatus of this invention comprises electrical circuitry in which a secondary load, such as a lamp, will receive current when and only when a primary load, suchas a refrigerator motor, receives current. This invention thus provides means whereby a light or lights in a home may be automatically turned on and off in a random fashion even though the home is unoccupied.
Motors in refrigerators and freezers operate automatically from time to time and for varying lengths of time in order to maintain the device at a preset temperature. Such operation, as by use of thermal switches, is a builtin feature of modern refrigerators and freezers. Other appliances or devices may also have such random on and off operating characteristics of course.
A light located externally of a refrigerator and the refrigerator motor are both connected to a voltage source. The main terminals of a triac are electrically connected in series with the light. A current transformer has its primary winding connected in series with the voltage source and the refrigerator motor. The secondary winding of the transformer has one end connected to the cathode of the triac and its other end connected through a resistor to the gate of the triac.
When current from the voltage source flows to the motor, as occurs-when the thermal switch actuates the motor, a current in the secondary winding of the transformer will be applied to the gate of the traic. The values' of the circuit elements are such that this gate current will cause the triac to switch from its nonconducting state'to its conducting state. During such time as the triac conducts, the electrical circuit which includes the voltage source, the triac, and the lamp is completed and the lamp is turned on. When current to the motor ceases, the current in the transformer secondary also ceases. The triac again reverts to its nonconducting state thus opening the circuit which includes the light.
BRIEF DESCRIPTION OF THE DRAWING The invention is illustrated in the drawing which is a schematic diagram.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT For ease of discussion, the detailed description of this invention will utilize the example where a source of illumination, such as a lamp, is automatically turned on and off simultaneously with the random on and off operation of household refrigerator.
A refrigerator motor 10, or primary load, is connected by leads l2 and 14 to a soure of voltage 16, such as an ordinary l 10 volt A.C. household outlet. The lead 12 is connected to the primary winding 18 of a step down current transformer 20 and to motor 10. Leads 24, 26, and 28 connect a lamp 30, or secondary load, and a triac 32 in series with the'voltage source 16.
The triac 32 has an anode 34 and a cathode 36 which are its main terminals, and a gate electrode 38. The secondary winding 39 of the transformer 20 has its one end 40 connected by the lead 42 to the cathode 36 of the triac. The other end 44 of winding 39 is connected by a lead 46 through a resistor 48 to the gate 38.
The refrigerator is designed to be maintaned at preset temperatures, and to that end it is constructed so that its motor will be automatically turned on and off as needed. Typically, random on and off conditions occur. When the motor 10 is turned on, for example, by operation of a thermal switch, it receives current from the voltage source 16. The current to the motor passes through the primary winding 18, which results in a current in the secondary winding 39 of the transformer 20. Since the winding 39 is connected to the cathode 36 and the gate 38 of the triac, the current from the winding 39 is applied to the gate 38. the values of a circuit components are selected so that such a gate current will cause the triac to switch from its non-conducting state to its conducting state. When the triac 32 conducts, the electrical circuit which includes the voltage source 16, the triac 32, and the lamp 30 is completed or closed, causing the lamp 30 to be simultaneously lighted.
When the motor 10 is turned off, there is no current to sustain the triac in its conducting state and the lamp 30 is simultaneously turned off.
I claim:
1. Apparatus for supplying current to a secondary load simultaneously with current flow from a voltage source to a primary load, comprising a secondary load connected to the voltage source and a triac, a current transformer having a winding connected to the voltage source and the primary load and having a winding with one end connected to the cathode of said triac and its other end connected through a resistor to the gate of said triac, whereby current flow from the voltage source to the primary load will initiate a flow of current to said gate electrode and cuase said triac to become conducting, thereby completing the circuit which includes the voltage source, the triac, and the secondary load.
2. Apparatus for operating a source of illumination in conjunction with the operation of an electrical appliance which is connected to a voltage source, comprising a source of illumination electrically connected in a circuit with a voltage source and a triac having anode, cathode, and gate electrodes, a current transformer having a primary winding connected to the voltage source and the appliance, said transformer having a secondary winding having one end connected to said cathode and its other end connected through a resistor to said gate electrode, whereby current to the appliance causes a gate current sufficient to cause the triac to switch to a conducting state to complete the electrical circuit which includes said source of illumination.
3. Apparatus for turning a lamp on and off simultaneously with the random on and off operation of a refrigerator motor which is connected to a voltage source, comprising a lamp located externally of the refrigerator, a triac having anode, cathode and gate electrodes, said lamp being connected to said voltage source and to said anode, a current transformer having a primary winding connected to the voltage source and the refrigerator motor, said transformer having a secondary winding having one end connected to said cathode and its other end connected through a resistor to said gate electrode, whereby said triac is in a nonconducting state when the refrigerator motor is off and is in a conducting state when the refrigerator motor is

Claims (3)

1. Apparatus for supplying current to a secondary load simultaneously with current flow from a voltage source to a primary load, comprising a secondary load connected to the voltage source and a triac, a current transformer having a winding connected to the voltage source and the primary load and having a winding with one end connected to the cathode of said triac and its other end connected through a resistor to the gate of said triac, whereby current flow from the voltage source to the primary load will initiate a flow of current to said gate electrode and cuase said triac to become conducting, thereby completing the circuit which includes the voltage source, the triac, and the secondary load.
2. Apparatus for operating a source of illumination in conjunction with the operation of an electrical appliance which is connected to a voltage source, comprising a source of illumination electrically connected in a circuit with a voltage source and a triac having anode, cathode, and gate electrodes, a current transformer having a primary winding connected to the voltage source and the appliance, said transformer having a secondary winding having one end connected to said cathode and its other end connected through a resistor to said gate electrode, whereby current to the appliance causes a gate current sufficient to cause the triac to switch to a conducTing state to complete the electrical circuit which includes said source of illumination.
3. Apparatus for turning a lamp on and off simultaneously with the random on and off operation of a refrigerator motor which is connected to a voltage source, comprising a lamp located externally of the refrigerator, a triac having anode, cathode and gate electrodes, said lamp being connected to said voltage source and to said anode, a current transformer having a primary winding connected to the voltage source and the refrigerator motor, said transformer having a secondary winding having one end connected to said cathode and its other end connected through a resistor to said gate electrode, whereby said triac is in a non-conducting state when the refrigerator motor is off and is in a conducting state when the refrigerator motor is on.
US00242573A 1972-04-10 1972-04-10 Random cycle load switch Expired - Lifetime US3763377A (en)

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4258368A (en) * 1979-03-29 1981-03-24 Emerson Electric Co. Safety means for preventing the automatic restart of a motor
US4365169A (en) * 1981-06-03 1982-12-21 Weston Allen H Random pulse detector system
EP0141213A1 (en) * 1983-10-21 1985-05-15 Robert Bosch Gmbh Current-controlled semiconductor relay
US5632007A (en) * 1994-09-23 1997-05-20 Actv, Inc. Interactive system and method for offering expert based interactive programs
US5724091A (en) * 1991-11-25 1998-03-03 Actv, Inc. Compressed digital data interactive program system
US7075899B2 (en) 2002-05-21 2006-07-11 Actv, Inc. System and method for providing private in-band data to digital set-top boxes in a broadcast environment
US7079176B1 (en) 1991-11-25 2006-07-18 Actv, Inc. Digital interactive system for providing full interactivity with live programming events
US7305691B2 (en) 2001-05-07 2007-12-04 Actv, Inc. System and method for providing targeted programming outside of the home
US7448063B2 (en) 1991-11-25 2008-11-04 Actv, Inc. Digital interactive system for providing full interactivity with live programming events

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3527957A (en) * 1968-05-31 1970-09-08 Minnesota Mining & Mfg Solid state remotely controlled circuit using control pulses

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3527957A (en) * 1968-05-31 1970-09-08 Minnesota Mining & Mfg Solid state remotely controlled circuit using control pulses

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4258368A (en) * 1979-03-29 1981-03-24 Emerson Electric Co. Safety means for preventing the automatic restart of a motor
US4365169A (en) * 1981-06-03 1982-12-21 Weston Allen H Random pulse detector system
EP0141213A1 (en) * 1983-10-21 1985-05-15 Robert Bosch Gmbh Current-controlled semiconductor relay
US7079176B1 (en) 1991-11-25 2006-07-18 Actv, Inc. Digital interactive system for providing full interactivity with live programming events
US5724091A (en) * 1991-11-25 1998-03-03 Actv, Inc. Compressed digital data interactive program system
US6181334B1 (en) 1991-11-25 2001-01-30 Actv, Inc. Compressed digital-data interactive program system
US6204843B1 (en) 1991-11-25 2001-03-20 Actv, Inc. Compressed digital-data interactive program system
US6215484B1 (en) 1991-11-25 2001-04-10 Actv, Inc. Compressed digital-data interactive program system
US6252586B1 (en) 1991-11-25 2001-06-26 Actv, Inc. Compressed digital-data interactive program system
US7448063B2 (en) 1991-11-25 2008-11-04 Actv, Inc. Digital interactive system for providing full interactivity with live programming events
US5632007A (en) * 1994-09-23 1997-05-20 Actv, Inc. Interactive system and method for offering expert based interactive programs
US7305691B2 (en) 2001-05-07 2007-12-04 Actv, Inc. System and method for providing targeted programming outside of the home
US7075899B2 (en) 2002-05-21 2006-07-11 Actv, Inc. System and method for providing private in-band data to digital set-top boxes in a broadcast environment

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