US3693047A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for protecting electrical devices
Assignee: General Electric Co
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Filing: 1971-09-28
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Granted: 1972-09-19
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Expires: 1991-09-28
Abstract
Abstract Apparatus for protecting electrical devices, particularly permanent magnet motors and components for controlling the speed of such motors, such as solid state elements, against excessive current and excessive temperature. A permanent magnet motor utilized for driving an electric appliance, such as a blender, is controlled by a circuit which includes a silicon-controlled rectifier in series with the motor. The SCR is mounted in heat transfer relationship with one side of a heat sink composed of a material having good heat conductivity. A thermally-actuated switch, connected in series circuit with the motor and the SCR, is positioned in heat transfer relationship with the opposite side of the heat sink. The heat sink is constructed so that its thermal mass may be easily modified to make the temperature of the heat sink correspond generally to the temperature of the motor, at least in the range of temperatures where protection is to be provided. The thermally-actuated switch is responsive to the heat sink temperature to protect the electrical devices against excessive temperature of the motor or of the SCR, and also is responsive to current through the resistance of the switch to protect against excessive current surge.
Inventors
- 👤 David C Hamstra
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:23
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/0833; H02H6/00
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
132 words
In an electrical appliance including a motor for driving the appliance and a solid state device for controlling the speed of the motor, apparatus for protecting the motor and the solid state device against overheating and overload comprising: a. a heat sink b. a thermally-actuated switch in series with the motor and the solid state device and mounted in heat exchange relationship with said heat sink c. said solid state device being mounted in heat exchange relationship with said heat sink whereby heat developed in said solid state device is transmitted to said switch d. said heat sink being selected of such thermal mass that its temperature corresponds approximately to the temperature of said motor in the region of maximum safe temperature for operation of said motor and said solid state device.
Claim 2
Dependent Claim
132 words
In an electrical appliance including a motor for driving the appliance and a solid state device for controlling the speed of the motor, apparatus for protecting the motor and the solid state device against overheating and overload comprising: a. a heat sink b. a thermally-actuated switch in series with the motor and the solid state device and mounted in heat exchange relationship with said heat sink c. said solid state device being mounted in heat exchange relationship with said heat sink whereby heat developed in said solid state device is transmitted to said switch d. said heat sink being selected of such thermal mass that its temperature corresponds approximately to the temperature of said motor in the region of maximum safe temperature for operation of said motor and said solid state device.
Claim 3
Dependent Claim
14 words
The apparatus of claim 1 wherein said solid state device is a silicon-controlled rectifier.
Claim 4
Dependent Claim
23 words
a thermally-actuated switch in series with the motor and the solid state device and mounted in heat exchange relationship with said heat sink
Claim 5
Dependent Claim
23 words
a thermally-actuated switch in series with the motor and the solid state device and mounted in heat exchange relationship with said heat sink
Claim 6
Dependent Claim
27 words
said solid state device being mounted in heat exchange relationship with said heat sink whereby heat developed in said solid state device is transmitted to said switch
Claim 7
Dependent Claim
27 words
said solid state device being mounted in heat exchange relationship with said heat sink whereby heat developed in said solid state device is transmitted to said switch
Claim 8
Dependent Claim
27 words
The apparatus of claim 1 wherein said heat sink is formed of a material of high heat conductivity for conducting heat rapidly from said solid state device.
Claim 9
Dependent Claim
39 words
The apparatus of claim 1 wherein said heat sink comprises a flat plate and wherein said switch is mounted on one face of said plate and said solid state device is mounted on the other face of said plate.
Claim 10
Dependent Claim
37 words
said heat sink being selected of such thermal mass that its temperature corresponds approximately to the temperature of said motor in the region of maximum safe temperature for operation of said motor and said solid state device.
Claim 11
Dependent Claim
37 words
said heat sink being selected of such thermal mass that its temperature corresponds approximately to the temperature of said motor in the region of maximum safe temperature for operation of said motor and said solid state device.
Claim 12
Dependent Claim
31 words
The apparatus of claim 4 wherein said heat sink further includes A flange extending from said plate and said flange has an opening therein for facilitating the mounting of said apparatus.
Claim 13
Dependent Claim
28 words
The apparatus of claim 4 wherein said plate is of generally rectangular configuration and said solid state device is mounted approximately in the center of said other face.
Claim 14
Dependent Claim
184 words
In an electrical appliance including a housing and a motor in the housing for driving the appliance and further including a solid state device for controlling the speed of the motor, apparatus for protecting the motor and the solid state device against overheating and overload comprising: a. a heat sink b. a thermally-actuated switch in series with the motor and the solid state device and mounted on said heat sink in heat exchange relationship therewith c. said solid state device being mounted on said heat sink in heat exchange relationship therewith whereby heat developed in said solid state device is transmitted to said switch d. said apparatus being positioned in said housing so as to be subject to the same ambient conditions as the motor e. said heat sink including a flange having an opening therein for facilitating the mounting of said apparatus on said housing f. said heat sink being selected of such thermal mass that its temperature corresponds approximately to the temperature of said motor in the region of maximum safe temperature for operation of said motor and said solid state device.
Claim 15
Dependent Claim
184 words
In an electrical appliance including a housing and a motor in the housing for driving the appliance and further including a solid state device for controlling the speed of the motor, apparatus for protecting the motor and the solid state device against overheating and overload comprising: a. a heat sink b. a thermally-actuated switch in series with the motor and the solid state device and mounted on said heat sink in heat exchange relationship therewith c. said solid state device being mounted on said heat sink in heat exchange relationship therewith whereby heat developed in said solid state device is transmitted to said switch d. said apparatus being positioned in said housing so as to be subject to the same ambient conditions as the motor e. said heat sink including a flange having an opening therein for facilitating the mounting of said apparatus on said housing f. said heat sink being selected of such thermal mass that its temperature corresponds approximately to the temperature of said motor in the region of maximum safe temperature for operation of said motor and said solid state device.
Claim 16
Dependent Claim
49 words
In an electrical appliance, a. a permanent magnet direct current motor for driving the appliance b. a solid state device in series with said motor for controlling the speed of the motor, and c. apparatus for protecting the motor and the solid state device against overheating and overload comprising:
Claim 17
Dependent Claim
49 words
In an electrical appliance, a. a permanent magnet direct current motor for driving the appliance b. a solid state device in series with said motor for controlling the speed of the motor, and c. apparatus for protecting the motor and the solid state device against overheating and overload comprising:
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-19 | 1976-03-20 | 1976-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-19 | 1980-03-20 | 1980-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-19 | 1984-03-20 | 1984-09-19 | $7700.00 | Window Closed / Lapsed |