Temperature detection method and apparatus

Abstract

A resistance temperature detector device and system are provided for measuring the temperature adjacent to windings within a stator assembly. The resistance temperature detector comprises a resistive element enclosed within a plurality of insulative layers, including insulation panels and adhesive. These surrounding insulation layers are sufficient to prevent partial discharge within any air gaps or low dielectric materials adjacent to the resistive element when the resistance temperature detector is disposed within a motor. A method for detecting temperatures between windings of an electrical machine is also provided.

1 . A resistance temperature detector system for detecting temperatures between windings of an electrical machine, the system comprising: 
 a winding configured to receive an alternating current voltage waveform during operation, the winding having a winding insulating system disposed about a central conductor; and    a resistive temperature detector disposed adjacent to the winding for detecting a temperature of the winding during operation, the detector comprising a resistive element configured to receive a measurement signal and to produce an output signal that is a function of temperature, and a detector insulating system disposed about and completely encasing the resistive element;    wherein the combination of the winding insulating system and the detector insulating system have a capacitance sufficient that a voltage stress level experienced by any air voids or low dielectric materials adjacent to the resistive element resulting from voltage applied to the winding during operation is below a stress level that would cause partial discharge in such voids and materials.    
   
   
       2 . A resistance temperature detector system for detecting temperatures between windings of an electrical machine, the system comprising: 
 a stator having a plurality of winding slots;    a plurality of windings disposed in the winding slots and configured to receive alternating current voltage waveforms during operation, each winding having a winding insulating system disposed about a central conductor; and    a resistive temperature detector disposed between adjacent windings in at least one of the slots for detecting a temperature of the adjacent windings during operation, the detector comprising a resistive element configured to receive a measurement signal and to produce an output signal that is a function of temperature, and a detector insulating system disposed about and completely encasing the resistive element;    wherein the combination of the winding insulating system and the detector insulating system have a capacitance sufficient that a voltage stress level experienced by any air voids or low dielectric materials adjacent to the resistive element resulting from voltage applied to the winding during operation is below a stress level that would cause partial discharge in such voids and materials.    
   
   
       3 . A method for detecting temperatures between windings of an electrical machine, the method comprising: 
 providing a resistive element configured to receive a measurement signal and to produce an output signal that is a function of temperature;    disposing the resistive element within a detector insulating system to form a detector, the detector insulating system having a desired capacitance per unit area of sufficient magnitude that a voltage stress level experienced by any air voids or low dielectric materials adjacent to the resistive element resulting from voltage applied to the windings during operation is below a stress level that would cause partial discharge in such voids and materials.    
   
   
       4 . The method of  claim 3 , further comprising coupling the resistive element to connection plates for supply of the measurement signal and for detection of the output signal.  
   
   
       5 . The method of  claim 4 , further comprising coupling the connection plates to a set of lead wires including a compensation lead wire.  
   
   
       6 . The method of  claim 3 , wherein disposing the resistive element within the detector insulating system includes joining a plurality of flexible insulative layers about the resistive element.  
   
   
       7 . The method of  claim 6 , wherein the flexible insulative layers comprise a polyimide, polyester, polyamide-imide, polyetheretherketone, polysulfone or polyphenylene sulfide.  
   
   
       8 . The method of  claim 6 , wherein the flexible insulative layers are joined by an adhesive.  
   
   
       9 . The method of  claim 8 , wherein the adhesive and the flexible insulative layers are selected to reduce the voltage stress across and incidence of partial discharge within any air gaps or other low dielectric materials disposed adjacent to the resistive element.  
   
   
       10 . The method of  claim 8 , wherein the flexible insulative layers and the adhesive have dielectric constants between approximately 3 and 6.  
   
   
       11 . The method of  claim 3 , further comprising disposing the detector between adjacent windings of an electrical machine stator.  
   
   
       12 . A device comprising: 
 a sensor configured to determine a parameter of an electromechanical system; and    an insulating system disposed about the sensor, the insulating system comprising one or more layers of a flexible insulating material and one or more layers of an adhesive, wherein the sensor is disposed within the one or more layers of adhesive, and the adhesive has a dielectric constant substantially equal to or greater than that of the flexible insulating material.    
   
   
       13 . The device of  claim 12 , wherein the layers of adhesive and flexible insulating material each have dielectric constants between approximately 3 and 6.  
   
   
       14 . The device of  claim 12 , wherein the flexible insulating material comprises polyimide.  
   
   
       15 . The device of  claim 14 , wherein the adhesive comprises an acrylic adhesive.  
   
   
       16 . The device of  claim 12 , wherein the flexible insulating material comprises polyester, polyamide-imide, polyetheretherketone, polysulfone or polyphenylene sulfide.  
   
   
       17 . The device of  claim 12 , wherein the adhesive is selected from the group consisting of epoxy, silicone, polyester, and polyurethane adhesive systems.  
   
   
       18 . The device of  claim 12 , wherein the parameter comprises temperature.  
   
   
       19 . The device of  claim 18 , wherein the sensor comprises a resistive element configured to receive an input signal via a lead and to produce an output signal that is a function of temperature.  
   
   
       20 . The device of  claim 12 , wherein electromechanical system is an induction motor, and the device is configured to be embedded within the induction motor adjacent to a winding of the induction motor.