Heating device with thermostat switch
View Patent ↗A system for wiring a heating element in an electrical appliance to a conventional thermostat switch in a new manner and a new thermostat for supporting the new wiring system. The new wiring system avoids switching the full heating element current for both hot power leads of a split-phase power system to reduce the amount of wiring needed to wire the thermostat switch to a heating element and a pilot lamp showing that current is being provided to the heating element.
1. A circuit for controlling an electrical heating element in an appliance, said circuit comprising:
a heating element including a first element terminal and a second element terminal;
a pilot light including a first pilot terminal and a second pilot terminal;
a thermostat switch including:
an element contact electrically connected to said second element terminal;
at least one power contact,
a pilot contact connected to a first pilot terminal,
a sensing device for detecting a temperature of said heating element,
an element switch for intermittently electrically connecting and disconnecting one of said at least one power contact to said element contact;
a control device adapted for receiving a temperature setting of a desired temperature of the electrical heating element, wherein said control device controls said element switch based on a temperature detected by said sensing device and also based on the temperature setting, wherein said control device is also adapted for preventing said element switch from making electrical contact between said one of said at least one power contact and said element contact when said control device is set in an off position, and
a pilot switch for electrically connecting said one or an additional one of said at least one power contact to said pilot contact when said control device is not in an off position and disconnecting said one or said additional one of said at least one power contact from said pilot contact when said control device is in the off position;
and
a split-phase power supply including:
a first voltage source electrically connected to said first element terminal bypassing said thermostat switch,
a second voltage source electrically connected to said one of said at least one power contact, and
a neutral terminal electrically connected to said second pilot terminal.
2. The system of claim 1 , wherein said thermostat switch further includes:
an additional power contact electrically connected to said one of said at least one power contact; and
an additional element contact that is not electrically connected to said first element terminal, wherein
said pilot switch electrically connects said pilot contact to said power contact via said additional power contact.
3. The system of claim 1 , wherein at least one additional switch is provided between said first voltage source and said first element terminal.
4. The system of claim 1 , wherein said pilot switch is sized to carry substantially the same current as said element switch.
5. The system of claim 4 , wherein said thermostat switch further includes:
the additional power contact electrically connected to said first voltage source utilizing a conductor that is sized to carry a substantially lower current than a maximum current carried by said heating element; and
an additional element contact that is not electrically connected to said first element terminal, wherein
said pilot switch electrically connects said pilot contact to said second power contact.
6. The system of claim 5 , wherein at least one additional switch is provided between said first voltage source and said first element terminal.
7. The system of claim 1 , wherein at least one additional switch is provided between said first voltage source and said first element terminal.
8. The system of claim 1 , wherein said pilot switch is sized to carry a substantially lower current than said element switch.
9. The system of claim 8 , wherein the voltage between said first voltage source and said second voltage source is about double the voltage between either of said first voltage source and said second voltage source and said neutral terminal.
10. The system of claim 1 , wherein said pilot switch is sized to carry the substantially same current as said element switch.
11. The system of claim 1 , wherein the voltage between said first voltage source and said second voltage source is about double the voltage between either of said first voltage source and said second voltage source and said neutral terminal.
12. The system of claim 1 , wherein said electrical heating element is a stovetop element, and wherein said thermostat switch is a user temperature control for said stovetop element.
13. A circuit for controlling an electrical heating element in an appliance, said circuit comprising:
a heating element including a first element terminal and a second element terminal;
a pilot light including a first pilot terminal and a second pilot terminal;
a thermostat switch including:
a first element contact electrically connected to said second element terminal;
a second element contact not electrically connected to said first element terminal;
a first power contact,
a second power contact;
a pilot contact connected to a first pilot terminal,
a sensing device for detecting a temperature of said heating element,
an element switch for intermittently electrically connecting and disconnecting said second power contact to said element contact;
a control device adapted for receiving a temperature setting of a desired temperature of the electrical heating element, wherein said control device controls said element switch based on a temperature detected by said sensing device and also based on the temperature setting, wherein said control device is also adapted for preventing said element switch from making electrical contact between said second power contact and said element contact when said control device is set in an off position, and
a pilot switch for electrically connecting said first power contact to said pilot contact when said control device is not in an off position and disconnecting said first power contact from said pilot contact when said control device is in the off position;
and
a split-phase power supply including:
a first voltage source electrically connected to said first element terminal utilizing a wire sized to carry a current to power the heating element, wherein said first voltage source is also connected to said first power contact using a wire sized for a current substantially less than the current to power the heating element,
a second voltage source electrically connected to said second power contact, and
a neutral terminal electrically connected to said second pilot terminal.
14. The system of claim 13 , wherein said pilot switch is sized to carry a current equal to or greater than said current to power the heating element.
15. The system of claim 13 , wherein the voltage between said first voltage source and said second voltage source is about double the voltage between either of said first voltage source and said second voltage source and said neutral terminal.
16. The system of claim 13 , wherein said electrical heating element is a stovetop element, and wherein said thermostat is a user temperature control for said stovetop element.
17. A method of using a thermostat switch to control the temperature of a heating element, said thermostat switch comprising:
a first element contact;
at least one power contact,
a pilot contact,
a sensing device for detecting a temperature of the heating element,
an element switch for intermittently electrically connecting and disconnecting one of said at least one power contact to said element contact;
a control device adapted for receiving a temperature setting of a desired temperature of the electrical heating element, wherein said control device controls said element switch based on a temperature detected by said sensing device and also based on the temperature setting, wherein said control device is also adapted for preventing said element switch from making electrical contact between said one of said at least one power contact and said element contact when said control device is set in an off position, and
a pilot switch for electrically connecting said one or an additional one of said at least one power contact to said pilot contact when said control device is not in an off position and disconnecting said one or said additional one of said at least one power contact from said pilot contact when said control device is in the off position;
said method comprising the steps of:
electrically connecting said first element contact to a first element terminal of said heating element;
electrically connecting a second element terminal of said heating element to a first voltage source bypassing said thermostat switch;
electrically connecting said one of said at least one power contact to a second voltage source;
electrically connecting said pilot contact to a first terminal of a pilot light; and
electrically connecting a second terminal of the pilot light to a common neutral terminal of the first and second voltage supplies.
18. The method of claim 17 , wherein said thermostat switch further comprises a second element contact and said additional power contact, said method further comprising the steps of:
electrically connecting the additional power contact to the first voltage source using a conductor sized for substantially less than a maximum current to be supplied to the heating element; and
not electrically connecting the second element contact to the heating element, wherein
said step of electrically connecting said one of said at least one power contact to a second voltage source is done using a conductor sized to carry a current greater than or equal to the maximum current to be supplied to the heating element.
19. The method of claim 18 , wherein at least one additional switch is provided between the first voltage source and the first element terminal.
20. The method of claim 19 , wherein said pilot switch is sized to carry substantially the same current as said element switch.
21. The method of claim 17 , wherein said pilot switch is sized to carry a substantially lower current than said element switch.
22. The method of claim 17 , wherein said pilot switch is sized to carry substantially the same current as said element switch.
23. The method of claim 17 , wherein at least one additional switch is provided between the first voltage source and the first element terminal.