Patent Publication Number: US-8527241-B2

Title: Wireless telemetry system for a turbine engine

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to monitoring operating environments and in particular to instrumented components and telemetry systems enabled for wirelessly transmitting electronic data indicative of individual component condition within an operating environment such as that of a combustion turbine engine. 
     BACKGROUND OF THE INVENTION 
     A wireless telemetry system for a turbine combustion is disclosed in U.S. application Ser. No. 11/936,936, which is incorporated herein by reference. As disclosed therein, a high temperature wireless telemetry system may be powered by induced RF energy generated by air gap transformers including a transformer primary induction coil assembly that is stationary and a secondary induction coil assembly that rotates. The telemetry system includes at least one sensor deposited on a component such as a turbine blade. A telemetry transmitter circuit is affixed to the turbine blade and a connecting material is deposited on the turbine blade for routing electronic data signals from the sensor to the telemetry transmitter circuit, the electronic data signals indicative of a condition of the turbine blade. An induction power system is provided for powering the telemetry transmitter circuit with a rotating data antenna affixed to the root of the turbine blade, such as the turbine blade; and a stationary data antenna affixed to a static seal segment adjacent to the turbine blade. 
     As shown in  FIG. 1 , the prior art telemetry transmitter assembly  300  is mounted to a side of a platform  301  supporting a turbine blade  302 . The transmitter assembly  300  is in electrical communication with a sensor (not shown) on the blade  302  via a first electrical connection  304 . The transmitter assembly  300  includes a cover member  303  bolted to a bracket member  305  with a transmitter circuit board disposed therebetween. The assembly  300  may be affixed to a transition area of the platform  301  in a recess  306  using an epoxy, adhesive, brazing, transient liquid phase bonding, diffusion bonding, welding, mechanical fixation, such as bolting, or any other joining method known to those in the art. A backfill material may be placed over them for protection from high temperatures or particulate debris. 
     A rotating data antenna assembly  308  is mounted to a face of the turbine root  301 , and is in electrical communication with the transmitter assembly  300  via a second electrical  310 . The antenna assembly  308  includes an induction coil and antenna secured within an RF transparent ceramic cover  311 , which is mounted to the face of the blade root  309  using a bracket  313 . The cover  311  includes flanges  312  secured in the bracket  313 , and the flanges  312  are oriented on the root  309  parallel with, rather than perpendicular to, the centrifugal force direction (represented by the arrow labeled “C”) of the rotating blade  302 , so the ceramic cover  311  is loaded in compression and not in bending. 
     While the above-described rotating antenna assembly  308  works for certain turbine engine designs, it may not be compatible with turbine blade sections that incorporate seal plates. Seal plates are often mounted to a turbine rotor disc on which the rotor blades are fixed to seal cooling fluid paths. However, the above-described rotating antenna assembly may not be used with seal plates. There is insufficient space between the seal plate and face of the root blade, and if the antenna assembly is capable of being mounted to the blade root face, the seal plate would interfere with transmission of signals from the antenna. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a prior art instrumented turbine blade including components mounted thereon for a wireless telemetry system. 
         FIG. 2  is a cross sectional view of an exemplary combustion turbine. 
         FIG. 3  is a perspective view of an exemplary combustion turbine vane. 
         FIG. 4  is a side view of an exemplary combustion turbine blade. 
         FIG. 5  is an exemplary heat flux sensor deposited on a substrate. 
         FIG. 6  is a perspective view of an exemplary turbine blade, sensor and wireless telemetry device. 
         FIG. 7  is a schematic of an exemplar wireless telemetry device. 
         FIG. 8  is a partial perspective view of turbine blades mounted in a rotor disc and seal plate structures mounted to the rotor disc and blade platform and the seal plate structure having telemetry components mounted thereon. 
         FIG. 9  is a side perspective view of a seal plate structure mounted to the rotor disc and blade platform and the seal plate structure having telemetry components mounted thereon. 
         FIG. 10  is an elevational view of the seal plate structure further illustrating an electrical connection of the telemetry components on the seal plate with a sensor on the turbine blade. 
         FIG. 11  is a perspective view of a first embodiment of a mounting bracket mechanism for mounting the telemetry components on the seal plate structure. 
         FIG. 12  is a perspective view of the first embodiment of a mounting bracket mechanism for mounting the telemetry components without the telemetry components. 
         FIG. 13  is a perspective view of a second embodiment of a mounting bracket mechanism for mounting the telemetry components on the seal plate structure. 
         FIG. 14  is a perspective view of the second embodiment of a mounting bracket mechanism for mounting the telemetry components without the telemetry components. 
         FIG. 15  is an exploded view of a telemetry transmitter assembly and corresponding bracket member. 
         FIG. 16  is a partial perspective view on a turbine static seal having an exemplary embodiment of a stationary antenna assembly mounted thereto. 
         FIG. 17  is a partial cross sectional view of a turbine stationary antenna, mounted to a stationary engine component, and a turbine blade assembly with a seal plate having an exemplary rotating power and antenna assembly mounted thereto. 
         FIG. 18  is a block diagram of an exemplary telemetry transmitter circuit. 
         FIG. 19  is a schematic of an exemplary induction power drive circuit. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 2  illustrates an exemplary combustion turbine  10  such as a gas turbine used for generating electricity. Embodiments of the invention may be used with combustion turbine  10  or in numerous other operating environments and for various purposes. Combustion turbine  10  includes a compressor  12 , at least one combustor  14  (broken away) and a turbine  16 . Compressor  12 , combustor  14  and turbine  16  are sometimes referred to collectively as a gas or combustion turbine engine  10 . Turbine  16  includes a plurality of rotating blades  18 , secured to a rotatable central shaft  20 . A plurality of stationary vanes  22  are positioned between blades  18 , with vanes  22  being dimensioned and configured to guide air over blades  18 . Blades  18  and vanes  22  will typically be made from nickel-based alloys, and may be coated with a thermal barrier coating (“TBC”)  26 , such as yttria-stabilized zirconia. Similarly, compressor  12  includes a plurality of rotating blades  19  positioned between respective vanes  23 . 
     In use, air is drawn in through compressor  12 , where it is compressed and driven towards combustor  14 . Combustor  14  mixes the air with fuel and ignites it thereby forming a working gas. This working gas temperature will typically be above about 1300° C. This gas expands through turbine  16 , being guided across blades  18  by vanes  22 . As the gas passes through turbine  16 , it rotates blades  18  and shaft  20 , thereby transmitting usable mechanical work through shaft  20 . Combustion turbine  10  may also include a cooling system (not shown), dimensioned and configured to supply a coolant, for example, steam or compressed air, to blades  18  and vanes  22 . 
     The environment within which turbine blades  18  and vanes  22  operate is particularly harsh, subject to high operating temperatures and a corrosive atmosphere, which may result in serious deterioration of blades  18  and vanes  22 . This is especially likely if TBC  26  should spall or otherwise deteriorate. Embodiments of the invention are advantageous because components may transmit real time or near real time data indicative of a component&#39;s condition during operation of combustion turbine  10 . 
     U.S. Pat. No. 6,576,861, the disclosure of which is specifically incorporated herein by reference, discloses a method and apparatus that may be used to deposit embodiments of sensors and connectors for connecting sensors with transmitters or otherwise routing data signals. In this respect, methods and apparatus disclosed therein may be used for the patterning of fine sensor and/or connector features of between about 100 microns and 500 microns without the need of using masks. Multilayer electrical circuits and sensors may be formed by depositing features using conductive materials, resistive materials, dielectric materials, insulative materials and other application specific materials. Alternate methods may be used to deposit multilayer electrical circuits, sensors and connectors such as thermal spraying, vapor deposition, laser sintering and curing deposits of material sprayed at lower temperatures may be used as well as other suitable techniques. 
       FIG. 3  illustrates a pair of adjacent vanes  23  removed from compressor  12  with one blade  23  having a sensor  50  mounted or connected thereto for detecting a condition of the vane. A lead line or connector  52  may be deposited as a means for routing a data signal from sensor  50  to a transceiver  54  configured for wirelessly transmitting the data signal to a receiver  56 . Alternatively, the data signal may be wired directly from the stationary vane component out of the engine. Connector  52  may be one or a plurality of electrical leads for conducting a signal from sensor  50  to transmitter  54 . Alternate embodiments allow for various types of connectors  52  to be used as a means for routing a data signal from sensor  50  to transmitter  54 , depending on the specific application. 
     Transmitters  54  may be multi-channel and have various specifications depending on their location within a casing of combustion turbine  10 . Transmitters  54  may be configured to function within the early stages of compressor  12 , which are subject to operating temperatures of between about 80° C. to 120° C. Transmitters  54  may be configured to function within later stages of compressor  12  and/or stages of turbine  16  subject to operating temperatures of greater than about 120° C. and up to about 300° C. Transmitters  54  may be fabricated using silicon-on-insulator (SOI) integrated circuit technology for wireless telemetry transmission circuits and other materials capable of operating in regions with temperatures greater than about 120° C. 
       FIG. 4  illustrates a schematic plan view of compressor blade  23  having sensor  50  connected therewith and connector  52  connecting sensor  50  with transmitter  54 . A power source  51  may be provided, such as an appropriately sized battery for powering transmitter or transceiver  54 . Transceiver  54  may receive signals from sensor  50  via connector  52  that are subsequently wirelessly transmitted to receiver  56 . Receiver  56  may be mounted on hub  58  or on a surface external to compressor  12  such as the exemplary locations shown in  FIG. 1 . Receiver  56  may be mounted in various locations provided it is within sufficient proximity to transmitter  54  to receive a wireless data transmission, such as an RF signal from transmitter  54 . 
     One or more sensors  50  may be connected with one or more compressor blades  23  by fabricating or depositing sensors  50  and connectors  52  directly onto a surface of blade  23 . Connector  52  may extend from sensor  50  to a termination location, such as the peripheral edge of blade  23  so that a distal end  53  of connector  52  is exposed for connection to transmitter  54 . Sensor  50  and connector  52  may be positioned on blade  23  to minimize any adverse affect on the aerodynamics of blade  23 . Embodiments allow for a distal end  53  of connectors  52  to be exposed at a termination location, which may be proximate a peripheral edge of a component or other suitable location. This allows a field technician to quickly and easily connect connector  52  to a transmitter  54  regardless of its location. 
       FIG. 5  illustrates an exemplary sensor  61  that may be deposited within a barrier coating such as TBC  60 , which may be yttria-stabilized zirconia. TBC  60  may be deposited on a bond coat  62 , which may be deposited on a substrate  64 . Substrate  64  may be various components such as a superalloy suitable for use in turbine  16  such as a turbine blade  18 . Sensor  61  may be formed for various purposes and may include thermocouples  66  deposited using conventional K, N, S, B and R-type thermocouple material, or any combination of their respective constituent elements provided that the combination generates an acceptable thermoelectric voltage for a particular application within combustion turbine  10 . 
     Type K thermocouple materials NiCr or NiAl may be used in sections of compressor  12  having an operating environment up to approximately 800° C. For example, NiCr(20) may be used to deposit a strain gage in compressor  12 . Type N thermocouple material, such as alloys of NiCrSi and NiSi, for example, may be used for depositing sensors in sections of turbine  16  having an operating environment between approximately 800° C. to 1150° C. 
     Type S, B and R thermocouple materials may be used for depositing sensors in sections of turbine  16  having an operating environment between approximately 1150° C. to 1350° C. For example, Pt—Rh, Pt—Rh(10) and Pt—Rh(13) may be deposited to form sensors  50  within turbine  16  provided that the material generates an acceptable thermoelectric voltage for a particular application within combustion turbine  10 . Ni alloys, for example NiCr, NiCrSi, NiSi and other oxidation-resistant Ni-based alloys such as MCrAlX, where M may be Fe, Ni or Co, and X may be Y, Ta, Si, Hf, Ti, and combinations thereof, may be used as sensing materials for high temperature applications in deeper sections of compressor  12  and throughout turbine  16 . These alloys may be used as sensing material deposited in various sensing configurations to form sensors such as heat flux sensors, strain sensors, pressure sensors, chemical species sensors, and wear sensors. 
     Components within combustion turbine  10 , such as blades  18 ,  19  and/or vanes  22 ,  23  may have application specific sensors  50  deposited to conform to a component&#39;s surface and/or embedded within a barrier or other coating deposited within combustion turbine  10 . For example,  FIG. 6  shows an exemplary turbine blade  70 , which may be a blade from row  1  of turbine  16 , having high temperature resistant lead wires, such as connectors  72  deposited to connect an embedded or surface mounted sensor  74  with a wireless telemetry device  76 . Device  76  may be mounted in a location where the telemetry components are exposed to relatively lower temperatures, such as proximate the root  78  of blade  70  where the operating temperature is typically about 150° C.-250° C. and higher. 
     Silicon-based electronic semiconductors, such as those that may be used for transmitting data may have limited applications due to their operational temperature constraints. Temperature and performance properties of silicon and silicon-on-insulator (SOI) electronic chip technologies may limit their applications to operating environments of less than about 129° C. Aspects of the invention allow for such electronic systems to be deployed for wireless telemetry device  76  within compressor  12 , which typically has an operating temperature of about 100-150° C. 
     Embodiments of wireless telemetry sensor systems may be configured to operate within higher temperature regions present in later stages of compressor  12 , and within turbine  16 . These regions may have operating temperatures of about 150-250° C. and higher. Materials having temperature and electrical properties capable of operation in these higher temperature regions may be used for depositing sensors  50 ,  74 , connectors  52 ,  72  and fabricating wireless telemetry devices  76 . 
     Sensors  50 ,  74  and high temperature interconnect lines or connectors  52 ,  72  may be deposited using known deposition processes such as plasma spraying, EB PVD, CVD, pulsed laser deposition, mini-plasma, direct-write, mini-HVOF or solution plasma spraying. Typically, dynamic pressure measurements, dynamic and static strain, and dynamic acceleration measurements are desired on both stationary and rotating components of combustion turbine  10  together with component surface temperature and heat flux measurements. Thus, embedded or surface mounted sensors  50 ,  74  may be configured as strain gages, thermocouples, heat-flux sensors, pressure transducers, micro-accelerometers as well as other desired sensors. 
       FIG. 7  is a schematic of a representative embodiment of a wireless telemetry device  76 . Device  76  may be formed as a circuit board or integrated chip that includes a plurality of electronic components such as resistors, capacitors, inductors, transistors, transducers, modulators, oscillators, transmitters, amplifiers, and diodes either embossed, surface mounted or otherwise deposited thereon with or without an integral antenna and/or power source. Embodiments of wireless telemetry device  76  may be fabricated for use in compressor  12  and/or turbine  16 . 
     Wireless telemetry device  76  may include a board  80 , an electronic circuit  90 , an operational amplifier  92 , a modulator  94  and an RF oscillator/transmitter  96  electrically connected with each other via interconnects  98 . The embodiment of  FIG. 6  is an exemplary embodiment and other embodiments of device  76  are contemplated depending on performance specifications and operating environments. Embodiments of device  76  allow for a power source  100 , and a transmitting and receiving antenna  102  to be fabricated on board  80  thereby forming a transmitter such as transmitter  54  shown in  FIGS. 3 &amp; 4 , or wireless telemetry device  76 , shown in  FIG. 6 . 
     Embodiments of the present invention provide components for use in combustion turbine  10  instrumented with telemetry systems that may include one or more sensors, lead lines connecting sensors with at least one telemetry transmitter circuit, at least one transmitting antenna, a power source and at least one receiving antenna. For example, embodiments of the present invention allow for transmitting sensor data from a rotating component, such as a turbine engine blade having certain electronic components located on a seal plate, which operates in an environment having a temperature of between about 300-500° C. For purposes of the disclosure herein, the term “high temperature” without additional qualification will refer to any operating environment, such as that within portions of combustion turbine  10 , having a maximum operating temperature of between about 300-500° C. 
     With respect to  FIGS. 8 ,  9  and  10 , a turbine blade section  110  of a combustion turbine is illustrated including a plurality of turbine blades  111  mounted to a rotor disc  112 . As shown, each blade  111  is supported on a platform  113 ; and, a root  114  is affixed to the bottom of the platform  113  and positioned within root channels (not shown) on the rotor disc  112  for positioning the blades  111  on the rotor disc  112 . In addition, a seal plate  115  is shown fitting in grooves  116 ,  117  in the platform  113  and rotor disc  112 , respectively, and covering faces of the blade roots  114 . As known to those skilled in the art, a locking mechanism (not shown) may be connected to the seal plate  115  and the rotor disc  112  and/or platforms  113  to secure the seal plate  115  in position. The seal plates  115  inhibit axial movement of the roots  114  relative to the rotor disc  112 . In addition, the seal plates  115  seal cooling fluid flow paths that extend to the upstream and/or downstream sides of the blades  111  adjacent lower surfaces of the platforms  113  defining an inner fluid flow path. 
     In an embodiment of the invention, one or more components of a wireless telemetry system, including the rotating data antenna assembly  116  and/or telemetry transmitter assembly  117 , are affixed to the seal plate  115  providing ease of access to such components. With respect to the previously described prior art in which the transmitter assembly is mounted directly to the blade platform, the entire blade must be removed in order to access the transmitter assembly. In the below-described embodiments, the transmitter assembly  117  and other components are mounted to the seal plate  115  and are accessible without removing the blades  111 , platforms  113  and roots  114 . In addition, if necessary, the seal plates  115  are removable to access the wireless telemetry components. 
     In reference to  FIGS. 9 and 10 , there is shown the wireless telemetry system including a sensor  118  disposed on an operating component such as the above-referenced blade  111 . As shown, the rotating antenna assembly  116  and telemetry transmitter assembly  117  are mounted on the seal plate  115 , which is in turn secured relative to the rotor disc  112  and platform  113 . The sensor  118  is in electrical communication with the below described electronics package of the transmitter assembly  117 , which includes a transmitter circuit (also referred to as a transceiver), via a first electrical connection  119 . The transceiver received induced power signals and data signals, and transmits data or data signals. 
     As shown, the first electrical connection  119  may include first lead lines or connectors  120  deposited on the blade  111  in connection with the sensor  118 , and on areas of the platform  113 . In addition, second lead lines  121  are secured to a surface of the seal plate  115  and connected to the transmitter assembly  117 . The transmitter assembly  117  is in electrical communication with the rotating antenna assembly  116  via a second electrical connection  122  that includes electrical lead lines  123  secured to the surface of the seal plate  115 . The lead lines  121  and  123  of the first  120  and second  122  electrical connection, respectively, may include electrical wires secured to the seal plate  115  with ceramic cement and/or tack welding techniques. 
     Embodiments of the invention may include a mounting bracket assembly including a first bracket  125  for affixing the rotating antenna assembly  116  to the seal plate  115  and a second bracket  126  for affixing the telemetry transmitter assembly  117  to the seal plate  115 . The brackets  125  and  126  are preferably fabricated or forged from the same metal alloy as the seal plate  115 . Accordingly, the seal plate  115  and bracket assembly  124  may be composed of a Ni-based superalloy or any other metal superalloy material that is suitable for components of a combustion turbine. 
     As shown in more detail in  FIG. 17  the rotating data antenna assembly  116  may comprise a rotating secondary induction coil assembly  127  contained within RF transparent cover  128 , which is mounted to the seal plate  115  using the first bracket member  124 . The rotating induction coil assembly  127  may be fabricated from a core  129  and winding  130 . A rotating data transmission antenna  131  is contained in RF transparent cover  128 , with a high temperature capable potting material  132  such as a ceramic cement material as known to those skilled in the art. In an alternative embodiment, the core  129 , winding  130  and antenna  131  may be secured in the cover  128  by packing these devices and cover with high temperature capable batting, such as can be fabricated from aluminum oxide fiber, or with other high temperate capable fibers. The batting serves to hold the devices in place with minimal weight added to the assembly, and can be pushed into the cover  128  so that the batting biases against the seal plate (or blade root as may be the case for the prior art systems) providing pressure between the cover  128  and first bracket  125 . This positive pressure between the cover  128 , bracket  125  and seal plate  115  reduces or eliminates impact between the induction coil assembly  127  and antenna  131  that might be caused by engine vibrations, while also allowing for relative motion to occur during heating and cooling that are caused by differences in thermal expansion between the metal mounting bracket  125  and the ceramic cover  128 . 
     The inventors of the present invention have determined that RF transparent cover  128  may be fabricated from an RF transparent, high toughness, structural ceramic materials. Ceramic matrix composites may be used to fabricate housing  128  as well as material selected from a family of materials known as toughened ceramics. Materials such as silicon carbide, silicon nitride, zirconia and alumina are available with increased toughness due to doping with additional elements and/or designed microstructures resulting from specific processing approaches. 
     One such material that is RF transparent, easy to form, and relatively inexpensive is a material selected from a ceramic family generally referred to as zirconia-toughened alumina (ZTA). Ceramic material selected from this family of aluminum oxide materials is considerably higher in strength and toughness than conventional pure aluminum oxide materials. This results from the stress-induced transformation toughening achieved by incorporating fine zirconium oxide particles uniformly throughout the aluminum oxide. Typical zirconium oxide content is between 10% and 20%. As a result, ZTA offers increased component life and performance relative to conventional pure aluminum oxide materials. Another exemplary material would be zirconia, partially stabilized with 3%-30% additions of oxides, such as magnesia (MSZ) and yttria (YSZ). 
     The designed microstructures of ZTA and YSZ are fracture-resistant when the ceramic is loaded in compression. However, if loaded sufficiently in tension, the ceramic will fail catastrophically, as with traditional ceramic materials. Consequently, RF transparent cover  128  is designed so that the tensile stresses in the ceramic material are minimized during operation of combustion turbine  10 . This is accomplished by designing and fabricating such that (1) all corners, edges and bends of the ceramic components are machined to eliminate sharp corners and edges, in order to reduce the stress concentration factor at these locations, and (2) the orientation and fit of the ceramic component in a rotating antennae mounting bracket  125  is such that during operation the G-forces applied to the ceramic box do not generate significant bending stresses in the attachment flanges. This is accomplished by orienting the flanges parallel with the G-loading direction, rather than perpendicular to the G-loading direction, so the ceramic flange is loaded in compression and not in bending. 
     As shown in  FIGS. 11 and 12 , the first bracket  125  includes two bracket members  138  and  139  spaced apart from one another for receiving the rotating antenna assembly  116 . The bracket members  138  and  139  are tilted toward one another and disposed at an acute angle or an obtuse angle relative to a surface  141  of the seal plate  115 , depending on the point at which such an angle may be measured. Accordingly, the cover  128  of the antenna assembly  116  has a wedge shaped cross-sectional configuration including sides  140  that are inclined toward one another and are similarly disposed at an acute angle or an obtuse angle relative to the surface  141  of the seal plate  115  depending on the point from which such an angle is measured. The angles at which the sides  140  of the cover  128  are disposed relative to the seal plate  115  are generally equal to the angle at which the brackets  138  and  139  are disposed relative to the surface of the surface  141  of the seal plate  115 . As shown, the bracket members  138  and  139  have planar surfaces abutting corresponding surfaces of the cover  128 , and apertures  142  for receiving retaining screws to secure the assembly  116  on the seal plate  115 . 
     Compared to the prior assembly shown in  FIG. 1 , in which the rotating antenna assembly is mounted to the face of a blade root, the seal plate  115  in the present invention provides a larger surface area for mounting the antenna assembly  116 . Accordingly, the antenna assembly  116  is larger and includes a larger antenna and larger induced power transformer coil assembly  127 . This translates to more power transmitted to the wireless transmitter circuit/transceiver. In addition, the increased power enables the transmission of signals/data across a wider distance while maintaining the same voltage supplied to the circuit board. The distance/gap between the rotating and stationary antennas (described below) in the wireless telemetry systems will change during operation of the combustion turbine  10 , increasing the distance/gap between the stationary and rotating antennas. Thus, the greater the distance/gap signals and data can be transmitted between the antennas creates a greater range of operation of the wireless telemetry system from combustion turbine engine startup to full engine operating temperatures. 
     In reference to  FIGS. 13 and 14 , there is illustrated an embodiment of the invention wherein the first bracket  125  includes the L-shaped bracket member  143  in conjunction with the inclined bracket member  139 . As shown, the antenna assembly  116  shown in  FIGS. 13 and 14  that is divided into two units including assemblies  116 A and  1168  and covers  128 A and  128 B, each having the above-described induced power transformer coil assembly  127  and antenna  131 . The assemblies  116 A and  116 B may include rotating assemblies that are each connected to a corresponding sensor and to the telemetry transmitter assembly  117  so that each antenna assembly  116 A and  1168  operates independently of the other. Alternatively, an antenna (not shown) may extend from one cover  128 A into the other cover  128 B, so that both assemblies operate as a single unit connected to a single sensor and the telemetry transmitter assembly  117 . 
     As shown in  FIGS. 11-15 , a preferred embodiment of the invention includes the second bracket  126  having a pocket type configuration having four walls  126 A- 126 D defining a recess  137  on the seal plate  115  or receiving the telemetry transmitter assembly  117 . Thus, the telemetry transmitter assembly  117 , may include the second bracket  126  and a lid or cover plate  136  with electronics package  133  positioned there between. A plurality of connecting pins  145  extend through the opening  144  and enable connection between an electronic circuit board contained within package  133 , such as one having a wireless telemetry circuit fabricated thereon, and various external devices such as lead lines from sensors, induction coil assemblies and/or data transmission antennae. Mounting bracket  126 , cover plate  136  and retention screws  118  connecting them together may all be fabricated from the same material as is seal plate  115 . This ensures there is no difference in thermal expansion between seal plate  115  and mounting bracket  126 . Consequently, no stresses are generated in mounting bracket  126  and/or seal plate  115  during thermal transients. 
     The electronics package  133  may contain a high temperature circuit board. The main body of electronics package  133  may be fabricated from alloys such as Kovar, an alloy of Fe—Ni—Co. The thermal expansion coefficient of Kovar ranges from about 4.5−6.5×10 −6 /° C., depending on exact composition. The Ni-based alloys typically used for high temperature turbine components, such as turbine blade  130  have thermal expansion coefficients in the range of about 15.9−16.4×10 −6 /° C. Electronics package  133  may be affixed securely in place while allowing for relative movement between electronics package  133  and seal plate  115 . This relative movement may result from their different thermal expansion rates, which occur over time during the high number of thermal cycles between ambient air temperature and the &gt;450° C. operating temperature typically experienced proximate seal plate  115 . 
     The thermal expansion coefficient of electronics package  133  may be less than that of mounting bracket  126  when the operating system within which these components reside is at a high temperature. Consequently, electronics package  133 , including any circuit board contained therein, would expand less than mounting bracket  126 , which may lead to damage caused by vibrational energy in the system. In order to secure electronics package  133  within mounting bracket  126  to accommodate the dimensional change differential between bracket  126  and electronics package  133 , a layer of ceramic fiber woven fabric  135  may be placed between the electronic package  133  and the inside surface of mounting bracket  126 . Fabric  135  may be fabricated from suitable ceramic fiber, including such fibers as silicon carbide, silicon nitride or aluminum oxide. For example, a quantity of Nextel™ aluminum oxide based fabric, manufactured by 3M, may be used for fabric  135 . Although, the embodiment of the invention illustrates the use of the fabric  135 , this fabric  135  is not required in all instances. 
     Cover plate  136  may be formed with a flange  146  oriented generally perpendicular to the direction of centrifugal forces (similar to that of the brackets members  138  and  139 ), to add structural support to the cover plate  136 , which counters the centrifugal forces occurring when rotor disc  112  is operating at full speed. This relieves retention screws  118  from carry the load applied to cover plate  136  via centrifugal forces, and allows them to be made sufficiently small so that the telemetry transmitter assembly  117  fits in a relatively small recess  137  of the bracket member  126  with no interference with any adjacent components. If retention screws  118  were required to carry the load applied by the centrifugal forces, their required size would be too large to fit in the available space. 
     Embodiments of the present invention may be powered by various means such as induced RF energy and/or by harvesting thermal or vibrational power within the combustion turbine engine  10 . In the energy harvested power model, either thermoelectric or vibro-electric power could be generated from the energy available in an operating combustion turbine engine  10 . Thermopiles may be used to generate electricity from thermal energy, or piezoelectric materials may generate electricity from vibration of combustion turbine engine  10 . Examples of these forms of power sources are described in U.S. Pat. No. 7,368,827, the entire disclosure of which is incorporated herein by reference. 
     Induced power modes are provided for powering components of wireless high temperature telemetry systems. Such systems may be configured as air-gap transformers where the transformer primary induction coil assembly  150  is stationary and the secondary induction coil assembly  127  rotates. For example, an induced RF power configuration is provided for powering a rotating telemetry transmitter circuit contained within telemetry transmitter assembly  117 .  FIG. 16  illustrates a portion of a static seal segment  151  such as one that may be used within the turbine engine  16  of combustion turbine  10 . A plurality of static seal segments  151  may encircle turbine engine  10  adjacent to a plurality of turbine blades  111 . Static seal segments  151  may cooperate with turbine blades  111  for sealing hot gas within a hot gas path through turbine engine  10  as recognized by those skilled in the art. 
       FIG. 16  shows an arcuate bracket  152  having respective channels or grooves formed therein within which a stationary data transmission antenna  153  and a stationary primary induction coil assembly  150  may be secured. Data transmission antenna  153  may be inserted into a non-conducting holder  154  for securing data transmission antenna  153  with bracket  152 . Non-conducting holder  154  ensures that data transmission antenna  153  does not contact bracket  152 , which may be fabricated of electrically conductive metal, thereby ensuring correct operation. Non-conducting holder  154  may be fabricated from the same toughened ZTA or YSZ ceramic material used for the RF transparent cover  128 . In the case of employing the antenna  153  in an arcuate bracket  152 , such as shown in  FIG. 16 , holder  154  may be segmented to provide flexibility, which allows for installation in curved bracket  152 . The same segmented configuration may be applied to the induction coil assembly  150  to enable installation in the bracket  152 . 
     Primary induction coil assembly  150  and data transmission antenna holder  154  may be formed with lobes in the region of attachment to bracket  152 . The associated regions of material in the bracket  152  are removed in the same lobe shape, with slightly larger size to accommodate installation. The lobe shape defines a radius of curvature that enables positive retention of induction coil assembly  150  and antenna and holder  153 ,  154 , which may be placed into bracket  152  from an end and slid into position. The lobe shape enables positive retention to be maintained while simultaneously ensuring that tensile stresses are not generated in induction coil assembly  150  and antenna holder  154 , both of which may be fabricated of relatively brittle materials subject to structural failure under tensile stresses. 
     The lobes may be positioned far enough from the front of induction coil assembly  150  and data transmission antenna  153  to ensure that metal bracket  152  does not interfere with electrical functionality. Ceramic cement may be applied between the surfaces of induction coil assembly  150  and antenna holder  154 , and their respective pockets in bracket  152 , in order to provide a secure fit and accommodate thermal expansion differences during heat up and cool down. A thin plate (not shown) may be attached on each end of bracket  152  that covers the lobed regions of the induction coil assembly  150  and the data antenna  153 , ensuring retention during operation. 
     One or more brackets  152  may be fabricated of the same alloy as static seal segment  151 , such as Inconel  625 , and have an arcuate shape to conform to the interior surface of static seal segment  151 . Bracket  152  may be affixed to the interior surface of static seal segment  151  using an interrupted weld  155  to minimize distortion of static seal segment  151 . Induction coil assembly  150  may include at least one stationary core  156  and at least one stationary primary winding  157  with ‘H Cement’  157  sold by JP Technologies, or any ceramic cement that is capable of electrically insulating and structurally protecting the windings, encasing portions of stationary core  156 . 
       FIG. 17  illustrates an embodiment having a rotating secondary induction coil assembly  127  contained within RF transparent cover  128 , which may be mounted proximate turbine engine blade root  132 . The rotating induction coil assembly  127  may be fabricated from a core  129  and winding  130 , similar to the stationary induction coil assembly  150 . A rotating data transmission antenna  131  may be provided for communication with stationary data transmission antenna  153 . Data transmission antenna  131  may be encased within a non-conducting holder (not shown), which may be similar in construction as non-conducting holder  154 . In an alternate embodiment, data transmission antenna  131  may be contained in RF transparent cover  128 , without use of non-conducting holder, in which case it may be held in place with a high temperature capable non-conducting potting material. Single or multiple stationary primary induction coils  150  may be arranged on the interior surface of one or more static seal segments  151  to form an arc that is circumscribed by rotating secondary induction coil assembly  127  and antenna  131  when combustion turbine  10  is in operation. 
     One or more stationary primary winding  157  may be energized by high frequency, high current power sources. The power can be supplied to each stationary induction coil assembly  150  individually, or a series of stationary induction coil assemblies  150  may be electrically connected and driven by a single power supply. In an exemplary embodiment there may be five adjacent, stationary induction coil assemblies  150  with each driven by its own power supply. The current flowing through each stationary primary winding  157  creates a magnetic field in the rotating secondary induction coil assembly  127  that in turn creates a current in the rotating secondary winding  130 . The current from rotating secondary winding  130  supplies power to a wireless telemetry transmitter circuit contained within wireless telemetry transmitter assembly  150  as described more fully herein below. 
       FIG. 17  illustrates that an initial gap “A” may exist between RF transparent cover  128  and stationary core  156  prior to startup of combustion turbine  10 . Initial gap “A” may be between about 1 mm to about 100 mm, and typically about 13 mm at startup of combustion turbine  10  and reduce to about 4 mm at baseload when turbine blade  130  and static seal segment  151  are closer together. Another engine configuration may result in an initial gap “A” of about  4 mm at startup of combustion turbine  10  and increase to about  90 mm at baseload when the turbine blade  130  and static seal segment  151  are farther apart. Magnetic core materials may be used to fabricate stationary core  156  and rotating core  129 . A magnetic material may be used as a core material in order to couple the required power to a telemetry transmitter circuit contained within telemetry transmitter assembly  150  over the required gap “A.” The selected magnetic material acts to focus the magnetic field produced by the stationary primary windings  157  and received by one or more rotating secondary windings  130 . This effect increases the coupling efficiency between the stationary and rotating elements. 
     Embodiments of induced power systems disclosed herein may employ multiple individual primary and secondary induction coil assemblies  150 ,  127  to accommodate various geometries with combustion turbine  10 . For instance, stationary induction coil assembly  150  and data transmission primary antenna  153  may need to span a certain distance of static seal segment  151  in order to induce enough power to the, system components and transmit the required data. An embodiment of induction coil assembly  150  and data transmission antenna  153  may need to be approximately four feet in length. In this example, for ease of fabrication, four individual power/antenna assemblies each with a length of approximately one foot may be fabricated with respective brackets  152  and installed adjacent to one another on one or more static seal segments  151 . If the end-to-end gap distance between the individual antennae is sufficiently small then the antenna assembly will function as if it were a single, four-foot long antenna. Such antenna assemblies may be formed from straight or curved elements thereby providing assemblies of varying lengths that are straight, curved or otherwise configured as required by the specific application. In an embodiment, a plurality of such antenna assemblies may span an arc of approximately 112 degrees in the top half of one or more static seal segments  151  within turbine  10 . 
     The inventors of the present invention have determined that a particular class of magnetic core materials meets or exceeds the performance requirements of embodiments of the present invention. The general term for this class of materials is a nanocrystalline iron alloy. One composition of this class of material is sold under the trade name NAMGLASS® and has a composition of approximately 82% iron—with the balance being silicon, niobium, boron, copper, carbon, nickel and molybdenum. It has been determined that such nanocrystalline iron alloy material exhibits desirable characteristics such as a Curie temperature greater than 500° C., very low coercivity, low eddy-current loss, high saturation flux density and the permeability is very stable over the entire high temperature operating range. 
     This nanocrystalline iron alloy material is commercially available in tape-wound configurations in the form of toroids, or “C” core transformer cores. Embodiments of the present invention utilize this nanocrystalline iron alloy material to form an “I” core shape, which was used for the primary stationary core  156 . The “I” shape was selected because this shape holds itself in place in the channel on stationary mounting bracket  152 . The induction core  156  of each induction coil assembly  150  consists of a plurality of 0.007″ thick laminations of nanocrystalline iron alloy material built up into an arc of approximately eleven inches in length. The same nanocrystalline iron alloy material may be used for the rotating antenna  131  transformer core. 
     The strength of the magnetic field used to couple power between the stationary and rotating elements may be increased by increasing the frequency of the driving signal, i.e., the high frequency AC signal produced by an exemplary induction power driver circuit illustrated in  FIG. 16 . Thus, embodiments of the present invention may employ a high frequency to drive the stationary primary windings  157 , such as frequencies greater than approximately 129 kHz. Alternate embodiments may achieve an operating frequency of at least one Mega-Hertz with a power driver designed to operate at such frequencies. The operating frequencies may range from approximately 150 kHz to approximately 500 kHz. 
     The wire used for winding cores  156 ,  129  may be made of a about 5% to about 40% nickel-clad copper with ceramic insulation in order to reduce oxidation and failure at high temperatures. The handling characteristics of this wire are significantly more challenging than standard organic-insulated bare copper, as a result of the protective, ceramic coating, and special techniques were developed for the processes of winding both the primary and rotating elements. Other wires may be insulated silver or anodized aluminum. 
     Two types of ceramic materials may be used in the construction of both the primary and rotating induction coil assemblies  150 ,  127 . It is important to ensure the windings  157 ,  130  do not short (conduct) to the core elements  156 ,  129 . In addition to ceramic insulation supplied on the wires, a compound, such as H cement, a ceramic cement with ultra fine particle size, may be used as an insulating base coat on the winding cores  156 ,  129 . Once the winding cores  156 ,  129  are wound they may be potted with Cotronics  940 , an aluminum oxide based ceramic cement. In an alternative embodiment, the insulating base coat and potting material may be Cotronics  940  or other ceramic cement material. 
       FIG. 18  illustrates a schematic of an exemplary telemetry transmitter circuit  210  that may be fabricated on a circuit board fitted inside high temperature electronics package  133  shown in  FIGS. 15 and 17 , which is contained within telemetry transmitter assembly  117 . Telemetry transmitter circuit  210  may be configured for operation with a sensor such as sensor  118  of  FIG. 10 , which may be a strain gauge sensor for measuring strain associated with turbine blade  130 . The rotating secondary induction coil assembly  127  may provide approximately 250 kHz AC power to the voltage rectifier of transmitter circuit  210 . This circuit changes the AC input to a DC output and feeds the voltage regulator circuit. 
     The voltage regulator of transmitter circuit  210  maintains a constant DC voltage output, even though the AC input voltage may vary. A constant voltage output is required to achieve better accuracy and stable operating frequency for the signal output. The voltage regulator also supplies a constant voltage, a strain gauge sensor  118  and a ballast resistor (not shown). The strain gauge sensor  118  and ballast resistor provide the sensor signal input to the transmitter circuit  210 . As the surface where the strain gauge sensor  118  is mounted deflects, the strain gauge changes resistance, which causes the voltage at the transmitter circuit  210  input to change. 
     The varying voltage provided by the signal from the strain gauge sensor  118  is amplified first by a differential amplifier and then by a high gain AC amplifier. The resulting signal is applied to a varactor diode in the voltage controlled oscillator (VCO) section of transmitter circuit  210 . The VCO oscillates at a high carrier frequency. This carrier frequency may be set in the band of 125 to 155 MHz with respect to transmitter circuit  210 . The fixed carrier frequency is changed slightly by the changing voltage on the varactor. This change in frequency or deviation is directly related to the deflection or strain undergone by strain gauge sensor  118 . The VCO carrier output is fed to a buffer stage and the buffer output connects to a transmitting antenna contained in the rotating antenna assembly  142  via lead wires  124  of  FIG. 10 . 
     In a receiving device, such as transceiver  56  in  FIGS. 2 and 3  or other devices located in high temperature or other areas within combustion turbine  10 , the carrier signal is removed and the deviation becomes the amplified output that is proportional to strain. The active circuit devices, such as diodes, transistors, and integrated circuits used in such a transmitter circuit  210  designed for high temperature use may be fabricated from a high temperature capable material, such as wide band gap semiconductor materials including SiC, AlN, GaN, AlGaN, GaAs, GaP, InP, AlGaAs, AlGaP, AlInGaP, and GaAsAlN, or other high temperature capable transistor material may be used up to about 500-600° C. 
     Various embodiments of wireless telemetry transmitter circuit  210  fabricated on a circuit board may be adapted for use within combustion turbine  10  at varying operating temperatures and with a range of sensor types. Elements of transmitter circuit  210  and alternate embodiments thereof may be fabricated using various temperature sensitive materials such as silicon-on-insulator (SOI) integrated circuits up to approximately 350° C.; polysilseqioxane, PFA, polyimide, Nomex, PBZT, PBO, PBI, and Voltex wound capacitors from approximately 300-350° C.; and PLZT, NPO, Ta 2 O 5 , BaTiO 3  multilayer ceramic capacitors from approximately 450-500° C. 
     Various embodiments of resistors may be fabricated of Ta, TaN, Ti, SnO 2 , Ni—Cr, Cr—Si and Pd—Ag for operating environments of approximately up to 350° C. and Ru, RuO 2 , Ru—Ag and Si 3 N 4  for operating environments of approximately 350° C. and greater. Individual high temperature electronic components, such as discrete transistor, diode or capacitor die made from SiC, AlN, GaN, AlGaN, GaAs, GaP, InP, AlGaAs, AlGaP, AlInGaP, and GaAsAlN, or other high temperature capable semiconducting material, may be replaced by a single SOI CMOS device for operation at temperatures not exceeding approximately 350° C. 
     While the preferred embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those of skill in the art without departing from the invention herein. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.