Abstract:
A method of switching the operating voltage of a portable generator system includes operating an electrical generator to produce a first electrical signal and connecting a terminal assembly to the electrical generator. The terminal assembly is arranged in a first arrangement to output a second electrical signal at a first voltage. The method also includes operating an auxiliary system in response to the second electrical signal at the first voltage, re-arranging the terminal assembly in a second arrangement to output the second electrical signal at a second voltage, and actuating a switch with a portion of the terminal assembly when the terminal assembly is in the second arrangement. The method further includes re-configuring the auxiliary system in response to the actuation of the switch such that the auxiliary system operates in response to the second electrical signal at the second voltage.

Description:
RELATED APPLICATION DATA 
       [0001]    This application claims benefit under 35 U.S.C. Section 119(e) of co-pending U.S. Provisional Application No. 60/870,183, filed Dec. 15, 2006, which is fully incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to a portable generator system operable at two or more voltages. More specifically, the invention relates to a portable generator system that is substantially automatically switchable between two or more voltages. 
         [0003]    Generators, and particularly portable generators, are often operable at two or more voltages to allow the generator to provide power to virtually any system that may require power. For example, 480 V systems and 240 V systems are commonly used throughout the United States. These systems are used interchangeably and in many applications are used in conjunction. Thus, a portable generator that is able to provide power at either voltage is beneficial. 
         [0004]    Generally, multiple electrical connections within the generator system must be changed to change the operating voltage. For example, the generator controls and monitoring equipment are generally powered by the generator and as such must be wired for the proper voltage. 
         [0005]    Some prior art constructions employ key-actuated switches to make some of the electrical connections required to change voltages. However, the use of keyed-switches is unpopular as the keys are often damaged or lost making a voltage change more difficult. Additionally, the exposure of the switch at an accessible terminal increases the likelihood of accidental undesirable switching. 
       SUMMARY 
       [0006]    In one construction, the invention provides a generator system that includes a prime mover and an electrical generator coupled to the prime mover and configured to produce a first electrical signal in response to operation of the prime mover. A terminal assembly is electrically connected to the electrical generator to receive the first electrical signal and output a second electrical signal. The terminal assembly is configurable in a first arrangement to output the second electrical signal at a first voltage, and in a second arrangement to output the second electrical signal at a second voltage. An auxiliary system is configurable to operate in response to the second electrical signal at one of the first voltage and the second voltage. The prime mover is operable in response to the auxiliary system. A switch is movable between a first position in which the auxiliary system operates in response to the second electrical signal at the first voltage, and a second position in which the auxiliary system operates in response to the second electrical signal at the second voltage. The switch is positioned such that the terminal assembly moves the switch from the first position to the second position in response to movement of the terminal assembly from the first arrangement to the second arrangement. 
         [0007]    In another construction, the invention provides a generator system that includes a prime mover, an electrical generator coupled to the prime mover and configured to produce a first electrical signal in response to operation of the prime mover, and a terminal assembly electrically connected to the electrical generator to receive the first electrical signal and output a second electrical signal. The terminal assembly is configurable in a first arrangement to output the second electrical signal at a first voltage, and in a second arrangement to output the second electrical signal at a second voltage. A first electrical output is configured to output the second electrical signal at the first voltage and a second electrical output is configured to output the second electrical signal at the second voltage. A switch is movable between a first position in which the second electrical signal is directed to the first electrical output and is inhibited from flowing to the second electrical output, and a second position in which the second electrical signal is directed to the second electrical output and is inhibited from flowing to the first electrical output. The switch is positioned such that the terminal assembly moves the switch from the first position to the second position in response to movement of the terminal assembly from the first arrangement to the second arrangement. 
         [0008]    In yet another construction, the invention provides a method of switching the operating voltage of a portable generator system. The method includes operating an electrical generator to produce a first electrical signal and connecting a terminal assembly to the electrical generator. The terminal assembly is arranged in a first arrangement to output a second electrical signal at a first voltage. The method also includes operating an auxiliary system in response to the second electrical signal at the first voltage, re-arranging the terminal assembly in a second arrangement to output the second electrical signal at a second voltage, and actuating a switch with a portion of the terminal assembly when the terminal assembly is in the second arrangement. The method further includes re-configuring the auxiliary system in response to the actuation of the switch such that the auxiliary system operates in response to the second electrical signal at the second voltage. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a portion of a generator system including an automatic voltage change device embodying the invention; 
           [0010]      FIG. 2  is a perspective view of the portion of the generator system including the automatic voltage change device in a first position; 
           [0011]      FIG. 3  is a perspective view of the portion of the generator system including the automatic voltage change device in a second position; 
           [0012]      FIG. 4  is a top view of the portion of the generator system including the automatic voltage change device of  FIG. 1  in the first position; 
           [0013]      FIG. 5  is a top view of the portion of the generator system including the automatic voltage change device of  FIG. 1  in the second position; 
           [0014]      FIG. 6  is a perspective view of a generator system including a housing or enclosure; 
           [0015]      FIG. 7  is a partially broken away view of the interior of the generator system of  FIG. 6 ; 
           [0016]      FIG. 8  is an enlarged front view of a portion of the housing of  FIG. 6  including output panels; and 
           [0017]      FIG. 9  is a schematic illustration of the generator system of  FIG. 6 . 
       
    
    
       [0018]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
       DETAILED DESCRIPTION 
       [0019]    A typical generator system  10  includes an enclosure or housing  15  (shown in  FIGS. 6 and 7 ) that encloses many of the generator system components and supports any external controls and displays. In some constructions, the housing is supported on a movable frame (i.e., wheeled frame) that allows for movement of the generator system  10 . An electrical generator  16  and a prime mover  17 , shown schematically in  FIG. 9 , are disposed substantially within the housing  15 . The electrical generator  16  may be a synchronous generator, an asynchronous generator, or an alternator if desired. In addition, other types of electrical generators are possible. So long as the electrical generator  16  is capable of outputting a current at the desired voltage and frequency and including the desired number of phases to a point of use, it is likely suitable for use in the generator system  10 . 
         [0020]    In some constructions, a rectifier and an inverter, or other signal conditioning components are employed to adjust an input current, or first electrical signal  18 , delivered by the electrical generator  16  to a desired frequency and/or voltage. The output of the signal conditioning equipment in these constructions is then delivered to the point of use. 
         [0021]    Many different prime movers  17  are suitable for use with the generator  16 , with gasoline or diesel engines being preferred. However, virtually any prime mover  17  capable of rotating the electrical generator  16  at the desired speed and torque could be employed as the prime mover  17 . For example, turbine engines (e.g., combustion turbine, microturbine, steam turbine, etc.) could be employed in some constructions if desired. 
         [0022]    Fuel for the prime mover  17  may be contained within the enclosure  15 , external to the enclosure  15 , or may be delivered to the prime mover  17  via an external source (e.g., pipeline, gas supply, etc.). In addition, the housing  15  generally includes one or more air intake paths that allow for the passage of external air to the prime mover  17  for combustion and cooling. An exhaust opening is also provided to allow for the discharge of exhaust gases that are produced during combustion. 
         [0023]    Additional components such as heat exchangers, cooling systems, valves, controls, fuel systems, etc, may also be located within the housing  15  to protect the components and to inhibit unwanted tampering. 
         [0024]    The generator system  10  includes a power output terminal assembly  20  that is connected to the electrical generator  16  such that the generated electricity, or first electrical signal  18  is delivered to the terminal assembly  20 . The terminal assembly  20  is also electrically coupled to at least one of a plurality of outputs that allow for the connection of electrical equipment to the generator system  10 . In a preferred construction, the terminal assembly  20  is arrangeable in one of at least two configurations to vary the output voltage of the generator system  10 . When arranged in a first arrangement ( FIGS. 1 and 2 ), the terminal assembly  20  delivers power, or a second electrical signal  29  at a first or low voltage to one of a plurality of first outputs  21  adapted to deliver power at the first or low voltage. When arranged in a second arrangement, the terminal assembly  20  delivers power at a second or high voltage to one of a plurality of second outputs  22  adapted to deliver power at the second or high voltage. 
         [0025]    In a preferred construction, the plurality of first outputs  21  includes a plurality of receptacles  23  arranged to deliver a specified amount of current at the desired voltage. Each of the receptacles  23  may include a fuse or breaker that inhibits the delivery of current in excess of the desired limit. Similarly, the plurality of second outputs  22  may include a plurality of similar receptacles  24  adapted to deliver power at the second voltage. 
         [0026]    In most constructions, the generator system  10  includes auxiliary systems  26  that may include a control system  26   a , a fuel delivery system  26   b , a voltage regulator  28 , and/or a plurality of indicators that are each powered by current provided by the generator  16 . As such, these components must be able to operate at the voltage delivered by the electrical generator  16 . Additionally, they must be switchable between these voltages. The voltage regulator  28 , shown in  FIG. 9 , is employed to deliver a field current or control to the electrical generator  16  to control the output voltage of the electrical generator  16 . Thus the voltage regulator  28  needs to be adjusted for the correct input voltage to assure the proper operation of the electrical generator  16  in the proper output voltage range. 
         [0027]    In prior art generator systems, a user must switch the electrical connections for each of these auxiliary systems as well as reconfigure the bus to switch between voltages. However, it is possible to forget to switch one or more of the components, thus resulting in improper operation of the system and potential damage to the improperly wired components. 
         [0028]    With reference to  FIGS. 1 ,  2  and  4 , the generator system  10  includes the terminal assembly  20  arranged in a first or low voltage configuration. A multi-pole switch  25  is positioned adjacent the terminal assembly  20  and includes multiple contacts  30  held within a switch body  35 , and an actuator  40  extending from the switch body  35 . The actuator  40  is biased into a first position as illustrated in  FIGS. 1 and 2 . The voltage regulator  28  and/or auxiliary systems  26  are electrically connected to the switch  25 , which in turn is electrically connected to the terminal assembly  20 . 
         [0029]    When the actuator  40  is in the first position, as illustrated in  FIGS. 1 ,  2 , and  4 , the electrical connections made by the contacts  30  within the switch  25  are such that the voltage regulator  28  and the other auxiliary systems  26  are wired for the first or low voltage. When the actuator  40  is moved to a second position, illustrated in  FIG. 3 , the contacts  30  within the switch  25  change such that the voltage regulator  28  and any other auxiliary systems  26  are wired for a second or high voltage. Thus, the wiring changes required to switch between voltages are automatically made by the switch  25 . 
         [0030]    However, to complete a voltage switch in the generator system  10 , the terminal assembly  20  must also be reconfigured. The terminal assembly  20  illustrated in  FIGS. 1 ,  2 , and  4  is configured for the first or low voltage. In this configuration, the actuator  40  extends into a space  45  and makes no contact with any other components. As such, the actuator  40  is biased into its first position. Thus, the terminal assembly  20 , the voltage regulator  28 , and the other auxiliary systems  26  are all arranged for the first or low voltage. 
         [0031]      FIGS. 3 and 5  illustrate the terminal assembly  20  arranged in the second or high voltage arrangement. In this arrangement, a bus bar  50  extends across the space  45  previously occupied by the actuator  40 . Thus, the bus bar  50  forces the actuator  40  into its second or high voltage position. Thus, the terminal assembly  20 , the voltage regulator  28 , and the other auxiliary systems  26  are all arranged for the second or high voltage. 
         [0032]    In use, an operator or user simply needs to properly configure the terminal assembly  20  in order to properly configure the generator system  10  for the desired output voltage. No knowledge is required as to what connections the switch  25  is making. So long as the user properly arranges the terminal assembly  20  (i.e., positions the bus bar  50 ), the proper electrical connections to the voltage regulator  28  and other auxiliary systems  26  will be made. 
         [0033]    In one construction, the generator system  10  includes an external indicator  60   a ,  60   b  (e.g., light) that indicates which voltage the generator system  10  is arranged to deliver. Such an indicator  60   a ,  60   b  can be easily controlled by the switch  25  to give the desired indication. While a light is described herein, any indicator perceptible to the user would be suitable for use. 
         [0034]    In some constructions, more than two arrangements of the terminal assembly  20  may be desired (e.g., a three voltage system). In these systems, multiple switches  25  could be employed or a three position switch could be employed to make the necessary connections between the terminal assembly  20  and the voltage regulator  28  and/or any other auxiliary systems  26 . 
         [0035]    It should be noted that the illustrated construction illustrates the switch  25  as being biased into the first or low voltage position. Of course, other arrangement could be biased into the high voltage position and thus require actuation to move to the low voltage position. As such, the invention should not be limited to the particular switch arrangement illustrated herein. 
         [0036]    In preferred constructions, the switch  25  is disposed within the housing  15  rather than on an operator accessible panel. Thus, unwanted or even accidental tampering with the switch  25  is inhibited. The location of the switch  25  is such that it is typically only intentionally actuated. 
         [0037]    The constructions illustrated herein reduce the likelihood of errors in electrical connections when a voltage switch is made, thereby reducing the likelihood of component damage or improper operation. Additionally, no keys or external devices are required to make voltage changes, thereby making an accidental partial voltage change (i.e., changing the connections for only a portion of the system) difficult. 
         [0038]    Thus, the invention provides, among other things, a generator system  10  operable to output power at two or more voltages. The generator system  10  is automatically switchable between at least two voltages.