Abstract An electric motor protector sensor for use in pressurized atmospheres comprises a small thermistor of low-thermal inertia which is carried in an opening in a thin, inner layer of flexible, temperature-resistant, electrically insulating material to expose portions of the thermistor on opposite sides of the thin insulating layer. Ends of lead wires are connected to these exposed thermistor portions, the lead wires extending away from the thermistor along opposite sides of the thin insulating layer to be connected at their opposite ends to the conductive cores of insulated conductors. Thin, flexible, disc-shaped foils of copper of much larger diameter or surface area than the thermistor are disposed on each side of the thin insulating layer in heattransfer engagement with respective exposed portions of the thermistor and with portions of the lead wires, thereby to provide heat-collecting members of substantial surface area in the sensor. Outer thin layers of similar insulating material sandwich the thin insulating layer and are bonded to opposite sides of the inner insulating layer around the copper foils, thermistor and leads for sealing the sensor. Heat-shrunk tubes of insulating material are disposed in sealing relation around portions of the insulated conductors and portions of the outer insulating layers of the sensor to complete sealing of the sensor.
A sensor comprising a thermistor material having selected temperature coefficient of resistance properties; an inner layer of flexible, electrically insulating material having an opening containing said thermistor and exposing portions of said thermistor of selected area on opposite sides of said inner layer; a pair of elongated electrically conductive lead members which are secured in electrically conductive relation to said thermistor portions exposed on respective opposite sides said inner layer and which extend from said thermistor portions along respective opposite sides of said inner layer of flexible electrically insulating material toward an edge of said inner layer of material; a pair of discrete, flexible foils of heatconducting material of relatively much greater area than said thermistor portions disposed on respective opposite sides of said inner layer in heat-transfer engagement with said thermistor portions and portions of said respective leads and in physical engagement with portions of said inner layer around said inner layer opening; and a pair of outer layers of flexible, electrically-insulating material disposed on respective opposite sides of said inner layer, said outer layers being bonded to said inner layer around said foils and leads for sealing said foils and thermistor therebetween.
Claim 2
Dependent Claim
194 words
A sensor comprising a thermistor material having selected temperature coefficient of resistance properties; an inner layer of flexible, electrically insulating material having an opening containing said thermistor and exposing portions of said thermistor of selected area on opposite sides of said inner layer; a pair of elongated electrically conductive lead members which are secured in electrically conductive relation to said thermistor portions exposed on respective opposite sides said inner layer and which extend from said thermistor portions along respective opposite sides of said inner layer of flexible electrically insulating material toward an edge of said inner layer of material; a pair of discrete, flexible foils of heatconducting material of relatively much greater area than said thermistor portions disposed on respective opposite sides of said inner layer in heat-transfer engagement with said thermistor portions and portions of said respective leads and in physical engagement with portions of said inner layer around said inner layer opening; and a pair of outer layers of flexible, electrically-insulating material disposed on respective opposite sides of said inner layer, said outer layers being bonded to said inner layer around said foils and leads for sealing said foils and thermistor therebetween.
Claim 3
Dependent Claim
21 words
A sensor according to claim 1 wherein the thickness of each foil is in the range from 0.40 to 0.75 mils.
Claim 4
Dependent Claim
25 words
A sensor according to claim 2 wherein the thickness of said inner and outer insulating layers is in the range from 2.0 to 6.0 mils.
Claim 5
Dependent Claim
46 words
A sensor according to claim 3 having electrical conductors with conductive cores and electrically insulating coatings on the conductive cores arranged so that the conductive cores of the insulated conductors are secured in electrically conductive relation to respective leads adjacent an edge of said inner layer.
Claim 6
Dependent Claim
32 words
A sensor as set forth in claim 4 having an insulating sleeve shrunk in sealing relation to said insulated conductors and said outer sensor layers for sealing said sensor to said conductors.
Claim 7
Dependent Claim
37 words
A sensor as set forth in claim 5 wherein said thermistor displays a selected temperature coefficient of resistance over a selected temperature range and displays a relatively different temperature coefficient of resistance over another selected temperature range.