Abstract:
A hydroelectric power-generating apparatus comprising: (1) a fluid inlet, (2) a diffuser having (a) at least one vane supporting a diffuser hub and (b) a rotor rotatably supported by the diffuser hub and having (i) impeller blades, (ii) an impeller hub, and (iii) a shroud at the periphery of the rotor, the shroud including at least one magnet, and (3) a housing surrounding the shroud and having a rigidly-attached stator including laminations and at least one electrical coil, whereby a flow of fluid through the diffuser and rotor causes the rotation of the rotor and the at least one magnet induces an electric current in the at least one coil.

Description:
RELATED APPLICATION 
     This application claims the benefit on U.S. Provisional Application 61/146,182 filed on Jan. 21, 2009, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to the low-cost generation of electrical power from waterways and coastal currents. 
     BACKGROUND OF THE INVENTION 
     Power generation from waterways and coastal currents is well-known and commonly practiced in coastal waters and rivers. A well-known application is in dams with built-in turbines driving generators for the production of electric power. Most navigable waterways have a controlled water level to facilitate shipping by maintaining minimum depths through the placement of dams in the waterway. Shipping is made possible through the location of locks adjacent to the dams. 
     The Mississippi River is an example of such a waterway with a controlled water level and a system of dams with locks. The water drop at most dams is 20 feet or less. One dam and lock has a drop of 38 feet and has been provided with a hydroelectric power plant taking power from the waterway. The 38 feet of static head provides an opportunity to produce power efficiently since the head is substantially greater than the other dams in this waterway. The static head in all other dams was not sufficient to provide a return-on-investment for a conventional hydroelectric power plant in conjunction with these dams. 
     The placement of dams also reduces and evens out the speed of the water flow, a benefit for the waterway shipping industry. Since flowing water has kinetic energy, it can also be used for power generation. However, the power level of an in-stream power-generating system is much smaller than what can be generated by a static-head-type turbine as mentioned above. 
     Both low-static-head and in-stream systems have traditionally not attracted interest because the cost of building the conventional equipment to generate this power was very high in relation to the benefit of the power produced. The present invention reduces the cost of the power-generating equipment to such a low level that power can now be efficiently and cost-effectively produced using existing dams with low static heads as well as waterways with a current. 
     Traditional generating systems consist of a turbine placed on a base, and the turbine is connected to a generator via a shaft and a coupling placed on that same base. In the case of an in-stream turbine, the turbine is suspended under a float with the electric generator, usually driven by a belt, placed on the float (where it is dry). The presence of a float makes it vulnerable to debris, waves and ice in a waterway as well as adding cost. The present invention lowers the cost of such an in-stream system such that it becomes economically feasible to generate electric power in this fashion. Also, the method of installation of such a system is greatly simplified. This invention allows efficient, low-cost power generation for both low-pressure static-head and in-stream systems that are not possible with conventional systems. 
     The cost reduction is accomplished by integrating the turbine and the electric power generator in one compact unit made of composite materials to keep both cost and weight low. It is modular in design, allowing combinations of components to select a match for the power requirement of a given application. It fits in-line with water ducts for easy installation and maintenance. It is submersible and can be suspended in a water current in ways that are not possible or practical with a separate turbine and generator. 
     Most conventional hydroelectric power generation systems do not have the capability of reversing the operation and turning the power generation system into a pumping system by applying an electric current to the generator. The present invention allows the electric generator to become an electric motor by reversing its function by changing the electronic commutation. The axial flow turbine functions equally well as a pump so that the inventive system can be used to store energy by applying to the unit electric power to be stored and pumping water from one reservoir to a higher-elevation reservoir. When the electronic commutation is reversed once again, it turns the power system back into a generator and so can recover the stored power. Therefore, unlike most conventional hydroelectric power generators, the present invention can be used as an energy storage and recovery system. 
     OBJECTS OF THE INVENTION 
     It is an object of this invention to provide a low-cost hydroelectric power-generating system which takes power from current in a waterway or coastal current that can efficiently produce electricity to economic benefit. 
     Another object of this invention is to produce a low-cost hydroelectric power-generating system that is fast and easy to install and service. 
     It is a further object of this invention to produce a low-cost hydroelectric power-generating system that permits applications that are conventionally not possible because of:
         physical constraints (no room to locate);   environmental constraints (conventional system too disturbing);   economic constraints (too costly to provide a positive return-on-investment);   no option to use the power-generating system as an energy storage device; and   a combination of the above.       

     It is a further object of this invention to produce a low-cost hydroelectric power-generating system that can efficiently make use of a static head in a waterway to produce electricity to economic benefit. 
     Another object of this invention is to produce a low-cost hydroelectric power-generating system that can be reversed to store energy by pumping water to a higher level and recover the stored energy when needed by switching back to power generation. 
     Another object of this invention is to produce a low-cost hydroelectric power-generating system that can efficiently make use of the static head of an existing dam to produce electricity to economic benefit without disturbing the existing dam structure. 
     Another object of this invention is to use the unique design that is efficient over a wide power range covering the full range of in-stream and static head inputs. 
     Another object of this invention is to maintain efficiency with higher static pressure heads by cascading two or more turbine/generator units in series. 
     Another object of this invention is to produce a low-cost hydroelectric power-generating system that can efficiently make use of a weir without the use of a duct. 
     Another object of this invention is the avoidance of the need to build a dam in order to capture the power-generating capability of a waterway. 
     Another object of the present invention is to provide the capability to use the same mechanical design adaptable to providing either AC or DC current by selecting appropriate power electronics. 
     Another object of the present invention is easy maintenance, whereby:
         a static-head unit placed in-line with a penstock is easily replaceable;   a sliding mechanism that allows the extraction of the generator is provided for easy service; and   an in-stream unit utilizes controllable flotation to enable easy above-water service.       

     Another object of the present invention is to provide a low-cost hydroelectric power-generating system with the following features:
         power generation with a turbine/generator having only one moving part;   low unit weight eliminating or reducing the need for a foundation;   in-line installation;   simple electronics packaged on the unit;   the use of composite materials; and   non-corrosive, submersible unit configuration.       

     Another object of the present invention is to provide a low-cost hydroelectric power-generating system that has the capability of in-stream power generation under all weather conditions, including high waves and the presence of debris and ice formation. 
     Another object of the present invention is to provide a low-cost hydroelectric power-generating system that siphons water over a dam without altering the structure of dam and which primes the siphon with pumped water or by applying a vacuum. 
     Another object of the present invention is to provide a low-cost hydroelectric power-generating system that uses selectable electrical poles and pole segments to provide a wide range of power levels with the same hydraulic hardware. 
     Yet another object of the present invention is to provide a low-cost hydroelectric power-generating system that has the capability of being transported and launched from a trailer at a boat ramp. 
     These and other objects of the invention will be apparent from the following descriptions and from the drawings. 
     SUMMARY OF THE INVENTION 
     The present invention is hydroelectric power-generating apparatus comprising: a fluid inlet; a diffuser having (1) vanes supporting a diffuser hub and (2) a rotor rotatably supported by the diffuser hub and having impeller blades, an impeller hub, and a shroud at the periphery of the rotor, the shroud including at least one magnet mounted thereto; and a housing surrounding the shroud and having a rigidly-attached stator including laminations and at least one electrical coil. A flow of fluid through the diffuser and rotor causes the rotation of the rotor, and the at least one magnet induces an electric current in the at least one coil. 
     In some preferred embodiments of the inventive hydroelectric power-generating apparatus, the diffuser is removably attached to the housing. In some preferred embodiments of the inventive hydroelectric power-generating apparatus, the stator is encapsulated with composite material to prevent fluid contact with the laminations and the at least one coil. Also, in some preferred embodiments, the housing has cooling grooves to cool the stator. 
     In other preferred embodiments of the inventive hydroelectric power-generating apparatus, the stator is segmented, and in some of these embodiments, the stator segments and the at least one coil are removable. In other such embodiments, the stator segments are held in place by spacer segments removably fastened to the housing. 
     In other preferred embodiments, of the hydroelectric power-generating apparatus, the at least one rotor magnet is held in place by a band around the shroud, and in yet other preferred embodiments of the inventive hydroelectric power-generating apparatus, the rotor is segmented, and each rotor segment has one or more impeller blades. 
     In highly-preferred embodiments of the inventive hydroelectric power-generating apparatus, the at least one magnet is placed at the tip(s) of the one or more impeller blades. 
     In highly-preferred embodiments, the inventive hydroelectric power-generating apparatus further includes an electronic commutation controller configured to reduce or increase the generator output by increasing or reducing torque load to control the water flow through the generator. 
     In some embodiments, the electronic commutation controller is connected to the at least one coil and configured to maintain a fixed AC output frequency by controlling the torque load on the stator. In some embodiments, the electronic commutation controller is connected to the at least one coil and configured to maximize the generator output as the fluid flow varies. In other embodiments, the electronic commutation controller is connected to the at least one coil and configured to switch from a power-generation mode to an electric motor mode, thereby changing the turbine into a pump. 
     In some preferred embodiments, the inventive hydroelectric power-generating further includes a penstock connected to the fluid inlet, directing fluid from an upstream fluid level through the hydroelectric power-generating apparatus to a lower downstream fluid level. In some embodiments, the apparatus is placed below the lower downstream fluid level, and the function of the hydroelectric power-generating apparatus is reversed by applying an electric current to the at least one coil, thereby causing the apparatus to pump fluid up the penstock to the upstream fluid level, thereby storing power. In some of these embodiments, the penstock is configured as a siphon reaching up to the upstream fluid level to siphon water into the penstock, and in some of these embodiments, the apparatus function is reversed, causing the apparatus to pump fluid up the penstock and siphon to the upstream fluid level until the siphon is primed. 
     In other embodiments, the inventive hydroelectric power-generating apparatus further includes a shut-off valve placed between the apparatus and the penstock, and a fluid supply valve placed in the siphon, such that when the shut-off valve is closed and fluid is supplied through the fluid supply valve, the penstock fills with fluid until the penstock overflows, thereby priming the siphon. Some of these embodiments include a vacuum pump to prime the siphon by drawing a vacuum at the high point of the siphon. 
     In some embodiments of the inventive hydroelectric power-generating apparatus, the apparatus is placed at the base of a weir, and in some of these embodiments, the apparatus configured to be removably attached to the weir. Further, the apparatus may include a slide mechanism supporting the apparatus and allowing the apparatus to be moved from an operating position into a service position. 
     In other embodiments of the inventive hydroelectric power-generating apparatus, the apparatus is submersed in the fluid flow and the flow drives the apparatus. In some of these embodiments, the apparatus is mounted on a skid, and in other such embodiments, the entire apparatus is configured to rotate in the waterway to align itself with the fluid flow to capture maximum flow. 
     In other embodiments if the inventive hydroelectric power-generating apparatus further include at least one float on which the apparatus is placed. 
     In some preferred embodiments of the invention, hydroelectric power-generating apparatus including a turbine and generator is mounted on a skid for submersed operation on the bottom of a waterway. Some of these embodiments include a plurality of turbines rotatably connected to the generator substantially in-line thereto via one or more couplings and one or more drive shafts to increase the total power generated by the apparatus. In other of these embodiments, the plurality turbines is connected to the generator via drive belts. 
     In some other preferred embodiments of the invention, hydroelectric power-generating apparatus, including at least one submersible float, thereby enabling the apparatus to be submerged. Some of these embodiments include a plurality of turbines rotatably connected to the generator substantially in-line thereto via one or more couplings and one or more drive shafts to increase the total power generated by the apparatus. In other of these embodiments, the plurality turbines is connected to the generator via drive belts. In other preferred embodiments, the hydroelectric power-generating apparatus, a gas is used to control the submersion and floatation of the at least one float. In yet other such embodiments, a buoy is connected to the at least one float to indicate the location of the apparatus while submerged, and a gas connection may be employed to control the submersion and floatation of the at least one float. Further, in some of these embodiments, the hydroelectric power-generating apparatus further includes at least two floats, and the apparatus is further configured to revolve to place the apparatus in an above-water service position. 
     On other embodiments, the hydroelectric power-generating apparatus which includes at least one float is configured to be launched and retrieved from a trailer. 
     Other preferred embodiments of the present invention include a plurality hydroelectric power-generating devices placed in series in a penstock which directs fluid from an upstream fluid level through the hydroelectric power-generating devices downstream, each device having: a fluid inlet; a diffuser having (1) at least one vane supporting a diffuser hub and (2) a rotor rotatably supported by the diffuser hub and having impeller blades, an impeller hub, and a shroud at the periphery of the rotor, the shroud including at least one magnet mounted thereto; and a housing surrounding the shroud and having a rigidly-attached stator including laminations and at least one electrical coil. A flow of fluid through the diffuser and rotor causes the rotation of the rotor, and the at least one magnet induces an electric current in the at least one coil. 
     The term “waterway” as used herein includes any body of water such as a river or a canal with a water current flowing through it. 
     The term “weir” as used herein refers to a fixed or removable barrier placed in a waterway to obstruct free water flow and produce a water level drop downstream, creating a static head between upstream and downstream of the weir. A weir may be provided with a port to allow water flow, and a turbine may be placed over such port to produce electric power. 
     The term “penstock” as used herein refers to a water feed pipe that provides the connection between the upstream side of a dam, weir or reservoir and a hydroelectric power turbine placed on the downstream side. 
     Laminates or laminations are thin magnetically-conductive sheet stampings of identical shape, that stacked together, form an electromagnetic flux guide in a plane parallel to the plane of the stampings. 
     A “dam” as used herein includes an upstream water level, usually at the top of the dam, and a downstream water level at the low side of the dam. 
     The term “static head” as used herein refers to the difference in elevation between the upstream and downstream water levels of a weir or dam. 
     The term “electronic commutation controller” as used herein refers to electronic circuitry which provides the function of motor/generator brushes and commutators through electronic switching. 
     The term “turbine” as used herein refers to rotating apparatus driven by fluid flow. 
     The term “pump” as used herein refers to rotating apparatus which drives fluid flow. 
     The term “tailrace” as used herein identifies the water duct downstream of the turbine/generator. 
     The term “turbine/generator” is used interchangeably herein with the terms “hydroelectric power-generating device” and “hydroelectric power-generating apparatus.” All such terms are sometimes, for convenience, referred to simply as a “device” with the corresponding reference number. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  (PRIOR ART) shows a conventional turbine and generator arrangement. 
         FIG. 1A  (PRIOR ART) shows a conventional in-stream turbine driving a generator. 
         FIG. 1B  (PRIOR ART) shows a conventional vertical-shaft hydroelectric turbine and generator configuration. 
         FIG. 2  illustrates the inventive turbine/generator in a vertical-shaft position and having a lifting-track mechanism. 
         FIG. 3  is a section of the integrated hydroelectric power generator in line with the axis of rotation. 
         FIG. 4  is a section of the integrated hydroelectric power generator perpendicular to the axis of rotation. 
         FIG. 4A  is an plan view of the lamination segment used in  FIG. 4 . 
         FIG. 5  is an end view of a continuous circular lamination. 
         FIG. 6  is a section of the integrated hydroelectric power generator perpendicular to the axis of rotation, showing the segmented stator in large segments. 
         FIG. 6A  is an end view of the lamination segment used in  FIG. 6 . 
         FIG. 7  is a section of the integrated hydroelectric power generator perpendicular to the axis of rotation, showing the segmented rotor and segmented stator. 
         FIG. 7A  shows the tapered segments and fasteners. 
         FIGS. 8A ,  8 B,  8 C and  8 D are block representations of combinations of stator and rotor arrangements in a reduced-power arrangement. 
         FIG. 9  is an elevation partial section of the hydroelectric power generator in an in-line static-head arrangement and applied to a dam. 
         FIG. 9A  is an elevation partial section of the hydroelectric power generator applied in dam-less run of waterway location. 
         FIG. 10  is an elevation partial section of the hydroelectric power generator in an in-line static-head arrangement, using a dam with two turbines in a cascaded configuration. 
         FIG. 11  is an elevation partial section of the hydroelectric power generator in an in-line static-head arrangement, using a dam with a siphon and priming device. 
         FIG. 12  is an elevation partial section of the hydroelectric power generator in an in-line static-head arrangement, using a dam with a turbine partially under the water. 
         FIG. 13  is an elevation partial section of the hydroelectric power generator in a static-head arrangement, using a weir with a turbine/generator in an operating position. 
         FIG. 14  is an elevation partial section of the hydroelectric power generator in a static-head arrangement, using a weir with the turbine/generator in a raised position for service. 
         FIG. 15  is an elevation partial section of the hydroelectric power generator in an in-stream arrangement, with the turbine/generator on a skid on the bottom of a waterway. 
         FIG. 15A  is an end view of the hydroelectric power generator in the arrangement of  FIG. 15 . 
         FIG. 16  is an elevation partial section of the hydroelectric power generator in an in-stream arrangement, on a skid on the bottom of a waterway and capable of alignment with the current. 
         FIG. 16A  is an end view of the hydroelectric power generator in the arrangement of  FIG. 16 . 
         FIG. 17  is an elevation partial section of the hydroelectric power generator in the arrangement of  FIG. 16  but with the water current flowing in the opposite direction. 
         FIG. 17A  is an end view of the hydroelectric power generator in the arrangement of  FIG. 17 . 
         FIG. 18  is an elevation partial section hydroelectric power generator in an in-stream arrangement, on submerged floats. 
         FIG. 18A  is an end view of a hydroelectric power generator in the arrangement of  FIG. 18 . 
         FIG. 19  is an elevation partial section hydroelectric power generator in an in-stream arrangement, on raised floats for maintenance and service. 
         FIG. 20  is the elevation view of a hydroelectric power turbine on floats placed on a trailer for transportation and launching from a boat ramp. 
         FIG. 20A  is the end view of a hydroelectric power turbine in the arrangement of  FIG. 20 . 
         FIGS. 21 and 21A  are elevation partial sections of cascaded in-stream turbine/generators coupled with drive shafts to the integrated turbine/generator on submerged floats. 
         FIG. 22  is an elevation partial section of flanked in-stream turbines coupled with drive belts to the integrated turbine/generator on submerged floats. 
         FIG. 22A  is an end view of flanked in-stream turbines in the arrangement of  FIG. 22 . 
         FIG. 23  is an elevation view partial section hydroelectric power generator in an in-stream arrangement, suspended from floats. 
         FIG. 23A  is an end view of the hydroelectric power generator in the arrangement of  FIG. 23 . 
         FIGS. 24A ,  24 B, and  24 C are end views illustrating the method of revolving the float-suspended hydroelectric turbine/generator for inspection and maintenance. 
         FIG. 24D  is an end view of the in-stream hydroelectric power generator arrangement of  FIGS. 23A-23C . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     While the principles of this invention have been described in connection with specific embodiments, it should be understood clearly that these descriptions are made only by way of example and are not intended to limit the scope of the invention. 
     The following detailed specification explains a novel approach to hydroelectric power generation starting with the integration of turbine and generator. This inventive concept will permit the application of hydroelectric power generation previously impossible by allowing configurations of systems previously mechanically impossible and by drastically lowering cost of manufacture, installation and maintenance, making systems efficient that were previously economically not feasible. 
       FIG. 1  (PRIOR ART) shows the conventional way of static-head hydroelectric power generation using a separate turbine  1  and generator  2  mounted on a common base  3  requiring a coupling  4 , a shaft  5 , and a shaft seal  6 . Further, there is the necessity of installation and alignment of turbine  1 , shaft  5  and generator  2  on the base  3 . This conventional installation requires an enclosure  7  and an electrical control panel  8 . A location has to be found or created to place base  3  convenient to the available waterway or dam to maintain the shortest piping runs. 
       FIG. 1A  (PRIOR ART) shows an in-stream hydroelectric power turbine  10  that is suspended below a float  11 , driving a generator  12  with a drive belt  13 . Generator  12  is placed on float  11  in an enclosure  14  to protect generator  12  and electrical switch gear  15  from the elements. Drive belt  13  connects turbine  10  with generator  12  through an opening  17  in float  11 . 
       FIG. 1B  (PRIOR ART) shows a conventional vertical-shaft water turbine  1 B and a generator  2 B in which a shaft  5 B connects to a transmission  6 B and a coupling  4 B connects transmission  6 B to generator  2 B. Transmission  6 B is placed on a base  3 B and inside an enclosure  7 B with an overhead service crane  9 B. 
     The present invention replaces the conventional design concepts shown in  FIGS. 1 ,  1 A and  1 B, eliminating the need for all of the components interconnecting the turbine with the generator and replacing these components with a simple configuration having one moving part that can be, but not necessarily is, made primarily of composite materials. The unit can be placed in line with the water flow for low-cost, efficient power generation above or under water. The configuration is capable of handling a wide range of power while keeping costs low by segmenting and modularizing the electric power-generating coils and the permanent magnets. It maintains common dimensions so that, for example, the same 60-inch diameter unit can handle 10 kW or 1500 kW, depending only on the selection of interchangeable components. 
       FIG. 2  shows a turbine/generator  20  (also herein referred to as hydroelectric power-generating device  20 ) oriented vertically above a tailrace  63 A. A vertical lifting track  62  enables the lifting of turbine/generator  20  to a position above the tailwater level  58  and the head water level  57 .  FIG. 2  also shows turbine/generator  20  as turbine/generator  20 A in a service position, in this case rotated 90 degrees for access. Turbine/generator  20  is shown mounted as a replacement unit in an existing structure  20 S and enclosed under a service deck  20 D having a removable hatch  20 H. 
       FIG. 3  shows turbine/generator  20  of the present invention in its basic embodiment in elevation section AA (see  FIG. 4 ).  FIG. 4  shows hydroelectric power-generating device  20  in elevation section perpendicular to its axis of rotation, also showing section lines BB of  FIG. 3 . A water supply duct  21  feeds water into a diffuser  22  and through a rotor  23  passing a set of impeller blades  23 A and from there to a water discharge duct  24 . Rotor  23  is rotatably supported by a hub  25  that in turn is held in place by a plurality of vanes  26  of diffuser  22 . Rotor  23  has an impeller hub  27 , and an impeller shroud  28  carries a set of permanent magnets  29 . A metal band  30  holds magnets  29  in place. Band  30  functions to limit radial expansion which may occur as a result of centrifugal force generated by the mass of impeller blades  23 A, shroud  28  and magnets  29  of rotor  23  while rotating. A housing  32  contains a stator  36 . Stator  36  contains a set of laminations  31  and a set of coils  33 . Laminations  31  and coils  33  are encapsulated with a composite material  35  to prevent contact with water. A set of electric leads  39  from coils  33  pass through a wire lead-out  37 . A drawing of a separate lamination  31  segment is shown in  FIG. 4A . 
     Diffuser  22  and a housing  32  are removably joined by a flange  38  of diffuser  22  to allow disassembly of the hydroelectric power-generating device  20 . A set of bolts  36 B holds diffuser  22  firmly to housing  32  while axial alignment is maintained by one or more register surface  41 . At the opposite end of device  20 , stator  36  is aligned by a register surface  42 . 
     A gap  34  is maintained between band  30  and composite encapsulating material  35  of stator  36  to avoid mechanical contact between rotating and stationary parts. 
     When water flows through intake  21  and diffuser  22 , its passage through rotor  23  will cause impeller blades  23 A, hub  27  and shroud  28  to rotate, moving magnets  29  past laminations  31  and inducing a electric current in coils  33 . Water will also flow through gap  34  between encapsulation material  35  and band  30 , effectively cooling stator  36  and housing  32  and magnets  29  from inside device  20 . Cooling is also effected by a set of cooling fins  32 R placed about the periphery of the housing  32 . 
     Laminations  31  may be in the form of a continuous ring  31 A as shown in  FIG. 5  or in segments (also numbered  31 ) as shown in  FIGS. 4 and 4A  in which each lamination segment  31  holds one coil  33 . Alternatively, as shown in  FIGS. 6 and 6A , lamination segments  31 B each hold multiple coils  33 . 
       FIGS. 3 ,  4  and  5  show generating systems set up for maximum power generation using a full complement of coils in device  20 . Many applications of this invention may operate at power levels significantly lower than the maximum possible power for a specific diameter of turbine/generator  20 . It is a cost advantage to use the same radial dimensions while lowering the power load significantly. One method of lowering the power output is to reduce the stack height of laminations  31  while maintaining the radial dimensions and turbine geometry of device  20 . A more efficient way is to limit the number of coils  33  and the span and number of lamination segments  31 ,  31 A or  31 B placed in housing  32 . This is done by segmenting stator  36  and laminations  31 B and coils  33  as shown in  FIG. 6 . As shown and labeled, assembled stator  40  includes laminations  31 ,  31 A or  31 B, coils  33 , and composite material  35 . Manufacturing stator segments  40  as segments significantly lowers the cost of manufacture when compared to producing stators  40  using continuous laminations  31 . 
     As shown in  FIG. 7 , a number of stator segments  40  can be removed and replaced with spacer segments  41  positioning stator segments  40 . Similarly, rotor magnets  29  can be placed at intervals to decrease the torque load on rotor  23  and consequently, the power generated. It is important to maintain a constant torque load throughout a single revolution to keep rotor  23  speed constant. In order to be able to maintain stator segments  40  fixed in place while being replaceable, segments  40  are wedged in place by spacer segments  41  not containing laminations or coils, and these are in turn held in place by fasteners  44 .  FIG. 7A  shows stator segments  40  and spacer segments  41  as well as the tapered shape of these parts so that tightening fastener  44  causes all segments to compress inside housing  32 . Stator segments  40 , like stator  36 , are encapsulated in composite material  35  to eliminate water penetrating coils  33  and laminations  31 ,  31 A or  31 B. Coil lead wires  39  are sealed by a wire lead-out  37  (see  FIG. 3 ) through which they pass out of stator segments  40 . The high cost of circular laminations  31  shown in  FIG. 5 , especially in larger diameters, favor the segmented configurations as shown in  FIGS. 6 and 7 . 
       FIG. 7  also illustrates that rotor  23  consists of rotor segments  42  and  43  each carrying one impeller blade  23 A. Only segments  42  carry magnets  29  in their peripheries. Band  30  holds magnet segments  42  and magnetless rotor segments  43  in place. 
       FIGS. 8A ,  8 B,  8 C and  8 D show, in schematic form, various arrangements of stator segments  40  external to circle at gap  34  and rotor segments  42  internal to this circle that provide a continuous and constant torque load during each revolution.  FIG. 8A  shows a minimal number of stator segments  40 ;  FIG. 8B  shows minimal rotor magnet segments  42 ;  FIG. 8C  shows same-sized rotor segments  43  and magnet segments  42 ; and  FIG. 8D  shows an arrangement with symmetrical torque load. 
     Referring again to  FIG. 3 , power leads  39  of stator  36  and each stator segment  40  are connected to a solid-state commutation controller box  44  attached to hydroelectric power-generating device  20 . The output connection to an inverter (not shown) is through leads  45 . The inverter (not shown) produces AC power from DC power by means well known to those skilled in the art. 
     The large number of poles, possible because of the diameter being large compared to that of a conventional generator, allows a wide range of DC voltage output and provides for optimization of power output over a wide range of speeds. 
     Electronic commutation control unit  44  is configured as a complete unit, is encapsulated and carries cooling fins so that it can operate above or under water or outside in all weather conditions. Electronic commutation controller  44  can be adjusted according to three possible power delivery modes: 
     1) Controller  44 , operating in AC mode, maintains constant rotor  23  speed (i.e., frequency). It controls torque to maintain constant speed to match the frequency of alternating current without the use of an inverter. The power delivery varies depending on water flow. Output voltage depends on power generated and may have to be transformed to a higher voltage of the power grid being supplied. 
     2) Controller  44 , operating in DC max-power mode, that provides optimal load (kW) under varying speed. This option will deliver the highest amount of power possible for a given water flow. It has DC output. Charge battery bank or be converted to AC via an inverter. 
     3) Controller  44 , operating in DC demand mode, provides output control by controlling the speed through torque load control to minimize water flow during low-kW demand for power from the generator. Output is DC. It may charge a battery bank or be converted to AC via an inverter. 
     Integrated turbine/generator  20 , employing a single moving part (rotor  23 ), allows the main components of device  20  to be made of composite materials, reducing cost, weight and corrosion. The modulus of elasticity of composite materials is significantly lower than that of metal. The inventive apparatus makes certain that any deflection under load is absorbed in a way that will not affect axial alignment of stator  36  and rotor  23 . 
     Here follow typical applications that make use of the unique features of the invention. Axial flow water turbines are generally capable of handling static heads from a few feet to up to 50 feet efficiently.  FIG. 9  shows turbine/generator  20  installed in a typical static head installation. A dam  56  retains water at an upstream level  57 . The static head created by dam  56  is the height differential between upstream level  57  and a downstream level  58 . A penstock  51  feeds water to device  20  via intake a set of grid bars  53  and a shut-off valve  52 . Penstock  51  is supported by several pipe supports  59 . Because of this unique configuration, turbine/generator  20  is light weight and makes it possible for it to be placed in-line at the end of penstock  51  in a cantilevered fashion without needing a mounting base or its own supports. Device  20  is removably attached to penstock  51  in a manner well-known in the art. 
       FIG. 9A  shows the inventive turbine/generator  20  in a non-dam application using the natural slope and features (i.e., local pools) of a suitable river bed. Grid bars  53  at the intake end of penstock  51  block debris from entering device  20 . Penstock  51  is mounted on suitably-positioned supports  59 . The static head of the river bed site spans between upstream level  57  and downstream level  58 , causing water flow through device  20  to extract power from such flow through penstock  51 . 
       FIG. 10  shows the placement of two units in series to deal with higher static heads, placing two identical turbine/generators  20  in line. The second device  20  is also placed in-line with penstock  51  and may not require additional support. The conventional method to handle the higher static head is to use a single, different-style turbine hydrodynamic design that is significantly more expensive to manufacture and far exceeds the cost of two of the present inventive devices  20 . Multiple integrated turbine/generators  20  can be cascaded in this manner to cover a wide range of static head pressures. Shut-off valve  52 , when closed, stops the operation of the turbine/generators  20  to allow inspection and maintenance and also cleaning of grid bars  53 . 
       FIG. 11  illustrates a method of generating power from an existing dam without the need to modify the dam. A siphon  55  is placed over the dam with one end connected to penstock  51  and the other end submerged below upstream water level  57  below the waterline. The upstream end of siphon  55  is provided with grid bars  53  to prevent debris from entering siphon  55 . Shut-off valve  52  is placed in penstock  51  adjacent to device  20 , and a water-supply valve  60  is placed on top of siphon  55  but over penstock  51  (see  FIG. 11 ) to ensure that water from valve  60  flows into penstock  51 . To prime siphon  55 , shut-off valve  52  is closed and water-supply valve  60  is opened filling penstock  51  with water. After penstock  51  is filled, water-supply valve  60  is closed and shut-off valve  52  is opened to start the water flow through device  20 . 
       FIG. 12  illustrates a second method of priming siphon  55 . Since integrated turbine/generator  20  hydrodynamic and electrical functions are fully reversible, applying power to device  20  will turn it into an axial flow pump. An axial flow pump needs to be submerged at least up to the shaft centerline to prime itself. Further, to prevent device  20  in pump mode from aspirating air, a tailrace  63  is placed on device  20 . When device  20  is energized, it will pump water up penstock  51  and through siphon  55 . As soon as water exits through grid bars  53 , the function of device  20  is changed back to power generation mode, establishing siphon flow through siphon  55 . 
     Since device  20  is below downstream water level  58 , servicing device  20  in this position would be difficult.  FIG. 12  also shows the installation of a catwalk  61  and vertical slide track  62  enabling device  20  to be raised for access for inspection and maintenance. Device  20 A is device shown in such raised position. 
     A third method to prime siphon  55  is also shown in  FIG. 12 . Vacuum valve  60 V, place at the high point of siphon  55 , is used to apply vacuum (vacuum pump not shown) to siphon  55  in order to draw water up into siphon  55 , filling penstock  51 . Siphon  55  start-up proceeds as previously described. 
     As shown above, the turbine/generator  20  function may be reversed, changing device  20  from a hydroelectric power generator to an axial flow pump and electric motor. This feature allows device  20  to function as an energy storage device by pumping water to a higher elevation level in a reservoir and reclaiming the power later by running device  20  as a turbine/generator. Electronic commutation controller  44  requires an input signal to switch functions from power generation to priming and pumping to reverse operation to store energy. Producing such a signal and control switching of controller  44  is well known to those skilled in the art. 
       FIG. 13  shows the placement of turbine/generator  20  at the bottom of a weir  70 . A slide valve  71  is shown in an open position and can be closed to stop the water flow through device  20 . Device  20  can be raised along vertical slide track  62  for service.  FIG. 14  shows slide valve  71  in a closed position and device  20  out of the water in such a service position. Catwalk  61  provides access for inspection and maintenance. 
       FIG. 15  shows turbine/generator  20  mounted on a skid  75  and submerged below water level  78  on the bottom  76  of a waterway. The water current represented by arrow  77  causes device  20  to produce electricity as explained in more detail above. Grid bars  53  deflect debris from entering device  20 .  FIG. 15A  represents an end view of skid  75  and device  20  on the bottom  76  of a waterway. 
       FIG. 16  shows a turbine/generator  20  mounted on skid  75  below waterline  78  with a vertical axis pivot  80  allowing the device  20  to rotate about axis  80  and align itself with current  77 . One or more vanes  79  are placed on device  20  to align device  20  with the prevailing current direction.  FIG. 17  shows the position of device  20  aligned with the reversed current  77 A.  FIGS. 16A and 17A  show end views of the respective positions of device  20  on skid  75 . 
       FIG. 18  shows a turbine/generator  20  mounted on submersible floats  81  which are submerged by internal flooding. An anchor  86  with an anchor line  85  attached to floats  81  keeps floats  81  from moving with the current. Anchor line  85  has a buoy  83  attached via line  87 . Attached to buoy  83  is a fitting  84  and a hose  88  connected to floats  81  to provide air pressure to displace the water in floats  81 , thus forcing floats  81  and device  20  to the surface for inspection and maintenance.  FIG. 19  shows device  20  out of the water floating on surface  78  on floats  81 . To return device  20  to service, the air is let out through fitting  84 . Buoy  83  identifies the location of device  20  when submerged. By supplying the appropriate amount of air, device  20  can be given neutral buoyancy and with the help of a combination of anchors, buoys and attachment to fixed and land based structures (not shown), the unit can be suspended in the current of a waterway away from surface  78  or bottom  76 .  FIG. 18A  shows an end view of the device  20  sitting on bottom  76 . 
     The transportation and placement of turbine/generators  20  on floats can be accomplished in the same way boats are launched from boat ramps on a trailer  85  as is shown in  FIGS. 20 and 20A . Larger units can be launched via commercial boat yards. 
     An in-stream power generator lacks the static head to provide substantial power and relies strictly on the kinetic energy from the water velocity. As a result, the power generated is a fraction of the power generated with static head systems. In order to operate the inventive power-generating device  20  efficiently, more power from other turbines, mechanically linked to device  20  can increase the power generated.  FIGS. 21 and 21A  illustrates such a system. Turbine/generator  20  is coupled to auxiliary turbines  86  by means of drive lines  88 , thus providing triple the power from device  20 . A set of baffles  89  serve to separate the exit stream of the upstream turbine (device  20  or turbine  86 ) from current flow into subsequent turbines. A set of grid bars  87  serve to keep out debris from turbines  86 . As before, device  20  and turbines  86  are mounted on submerging floats  81  to provide easy inspection and maintenance. 
     Another method of driving turbine/generator  20  is shown in  FIGS. 22 and 22A  by connecting adjacent turbines  86  with device  20  via belt drives  90 . Part of rotor  28  is provided with one or more grooves for interconnecting drive belts  90  transmitting power generated by the turbines  86  to the generator of device  20 . The assembly can be mounted on a set of submersible floats  81 . 
     Yet another method of suspending turbine/generator  20  in waterway current  77  is shown in  FIGS. 23 and 23A  where it is suspended from floats  81  and  91 . This method is preferred if waterway bottom  76  is uneven or rocky and proper alignment of device  20  on bottom  76  is not feasible. Floats  81  and  91  are anchored in the stream by anchor  86  and anchor line  85 . Other methods of anchoring such as fastening to bridge pylons or points on land (not shown) can maintain the floats in position. To inspect and maintain device  20 , float  91  is sealed to prevent sinking to bottom  76 . 
     As shown in  FIGS. 24A ,  24 B,  24 C and  24 D, by submerging float  81  and subsequently floating auxiliary float  92  and then re-floating float  81 , device  20  can be revolved to position device  20  above surface  78  for inspection and maintenance. By reversing this floatation cycle, device  20  can be returned to service.