Abstract:
A wireless annunciator for an electrical generator displays data regarding operation of the electrical generator to provide feedback to a remote observer regarding performance of the electrical generator in meeting the demands placed thereon. The wireless annunciator wirelessly receives transmissions from one or more wireless modules and displays information based on the data contained in the transmissions. The wireless modules may be associated with sensors, for example, that measure various performance parameters of the electrical generator, such as current draw, fuel level, fuel pressure, and the like. A load management controller can communicate with one or more load-side modules, either wirelessly or across wired links, to control operation of one or more loads to avoid overloading of the electrical generator.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Ser. No. 61/295,964, filed Jan. 18, 2010. 
     
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
       [0002]    The present invention relates generally to electrical generators and, more particularly, to a method and system for remotely monitoring and controlling a backup or emergency power supply system in which one or more electrical generator supply electrical power to an electrical system during interruption of utility or primary power. 
         [0003]    Electrical generators are commonly used to provide emergency or backup electrical power to an electrical system when utility power is unavailable. Electrical generators are commonly used to provide backup electrical power for office buildings, medical and nursing centers, hospitals, malls and shopping centers, airports, apartment complexes. These types of facilities will typically require multiple electrical generators to supply the required amount of electrical power to power critical loads, such as HVAC systems, emergency lighting systems, security systems, communication systems, medical equipment, etc. 
         [0004]    In some instances the multiple electrical generators are unable to meet the electrical demand. Accordingly, load management systems have been developed to electrically isolate electrical loads from the electrical generators. Various load management systems have been developed including some that acquire current usage data from the loads during normal operation and use that data to terminate electrical power to selected loads based on the total power draw on the electrical generators. One of the drawbacks of these power management or load control systems is that the lack of flexibility. That is, conventional load management systems are only operative during overload conditions and provide limited information regarding operation of the electrical generators, i.e., current draw on the generators. 
         [0005]    The present invention is directed to a wireless annunciator for an electrical generator or backup power supply system that displays data regarding operation of the electrical generator to provide feedback to a remote observer regarding performance of the electrical generator in meeting the demands placed thereon. The wireless annunciator wirelessly receives transmissions from one or more wireless modules and displays information based on the data contained in the transmissions. The wireless modules may be associated with sensors, for example, that measure various performance parameters of the electrical generator, such as current draw, fuel level, fuel pressure, and the like. A load management controller can communicate with one or more load-side modules, either wirelessly or across wired links, to control operation of one or more loads to avoid overloading of the electrical generator. 
         [0006]    Other objects, features, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0007]    The drawings illustrate the best mode presently contemplated of carrying out the invention. In the drawings: 
           [0008]      FIG. 1  is a schematic representation of a wireless annunciator system according to one aspect of the invention; 
           [0009]      FIG. 2  is a schematic representation of a wireless load management system according to another aspect of the invention; 
           [0010]      FIG. 3  is a schematic representation of a hybrid wired and wireless load management system according to a further aspect of the invention; and 
           [0011]      FIG. 4  is a flow chart illustrating a load management process. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    Turning now to  FIG. 1 , in one embodiment, the invention is directed to a wireless annunciator system  10  in which one or more wireless modules  12  are used to wirelessly transmit operational information regarding one or more electrical generators  14  to a dashboard  16  or similar graphical interface to allow a user to remotely monitor, and in some instances, modify operation of the one or more electrical generators. In addition to wireless modules  12  for the one or more electrical generators, the annunciator system  10  preferably includes wireless modules for other systems associated with the electrical generator, such as a wireless module  18  for fuel pressure and level sensors  20  of a fuel tank  22  that contains fuel (not shown) for the internal combustion engines (not shown) of the one or more electrical generators  14 . In the illustrated system, a single fuel tank is used to supply fuel for multiple electrical generators but it is understood that multiple fuel tanks could be used including a dedicated fuel tank for each electrical generator. Thus, it is further considered that multiple fuel pressure and level sensors may be required to monitor fuel and pressure levels in the multiple fuel tanks. In such an embodiment, it is contemplated that one or more ancillary wireless modules  18  may be used to wirelessly provide information to the wireless annunciator dashboard  16 . 
         [0013]    Still referring to  FIG. 1 , the electrical generators  14  provide backup or emergency power to an electrical system  24  through a transfer switch  26  when utility power  28  to the electrical system (“loads”) is unavailable. In a preferred embodiment of the invention, the wireless annunciator system  10  includes a wireless module  30  that provides information regarding operation of the transfer switch  26  to the dashboard  16 . For example, the transfer switch  26  may include current and/or voltage sensors (not shown) or a frequency sensor and the wireless module  30  could transmit current and/or voltage and other information regarding the power draw by the loads  24  to the dashboard  16 . 
         [0014]    It will be appreciated that each wireless module has circuitry (not shown) that allows the transmission and/or reception of data. It will be further appreciated that the modules can be configured with different interface options including digital I/O, analog inputs, and serial interfaces. Digital and analog inputs can be used for sensor inputs, switch inputs, and communication with a controller. The digital outputs can be used to activate display lights, text, relays, or run a buzzer, for example. The serial interface can be used to communicate with a generator controller or other microprocessor based systems. The system could also be setup to communicate with a cell phone, personal data assistant, computer, or other remote device to allow remote monitoring and control. 
         [0015]    A wireless module may be paired with, or include, a user interface, e.g., dashboard  16 , for the conveyance of information to a user regarding operation of the generator, such as fuel level. It is also contemplated that wireless modules could be associated with loads that are powered by the generator during utility power interruption or a transfer switch to control operation of the generator to meet the demands of a load network, e.g., home. 
         [0016]    For example, and turning now to  FIG. 2 , the wireless anunicator system described with respect to  FIG. 1  may be incorporated with a wireless load management system  32  in which wireless modules  34  are used to wirelessly provide operational and/or performance information regarding high current draw appliances, such as air conditioners  36  and normal or light current draw loads  38 . Additionally, it is contemplated that the wireless management system may include wireless contactor modules  38  that control the flow of electrical current either from a generator  14  or a utility power supply  28  to dedicated high current draw devices (“large loads”  40 ). In this regard, the wireless contactor modules  38  are capable of providing a switching function to selectively connect/disconnect the large loads  40  to either the generator  14  or the utility  28  based on command signals wirelessly transmitted thereto, such as from a load management controller  42  (via wireless module  44 ). Frequency information regarding the flow of electrical current to the various loads may be sensed by a frequency sensor  43  to provide information regarding the quality of electrical power being provided by the electrical generator  14  or the utility supply  28 . 
         [0017]    Wireless module  44  is communicatively linked with the load management controller  42  and is capable of receiving wireless transmissions from wireless modules  12  and  34  and wireless contactor modules  38 . Moreover, the wireless module  44  is capable of transmitting information, such as commands, to the wireless modules to effectuate changes in operations of the transfer switch  26 , generator  14 , dedicated appliances, e.g., AC units  36 , and large loads  40 . 
         [0018]    For example, wireless modules  34  may receive information from thermostats  46  for the AC units  36  and convey that information to wireless module  44  which is then communicated to the load management controller  42 . Based on the demands being placed on the generator  14 , for example, the load management controller  42  may construct a message that is transmitted to wireless module  34  via wireless module  44 . Upon receipt of the electronic message, the wireless modules  34  may then change a setting of the thermostat, such as to delay or accelerate operation the AC units, i.e., raise or lower the temperature setting of the thermostats  46 . In this regard, rather than turning on or shutting down of the AC units  36  automatically, the controller  42  can control operation of the AC units by changing the settings of the thermostats  46  to manage the power draw on the generator  14 . It will therefore be appreciated that the controller  42  can control operation of the loads, via communication with the wireless modules, to limit the power draw on the generator  14 . This is believed to be particularly advantageous in reducing the size of the generator  14  needed for a given electrical system. Reducing the size of the generator  14  not only can lead to reduction in purchasing and operating costs but can also provide a desirable reduction in noise emissions, which is a growing concern of municipalities, homeowners&#39; associations, and condominium managers. 
         [0019]    Referring briefly again to  FIG. 1 , it is contemplated that the graphical dashboard  16  could take one of many forms and could be configured to display information in one or more forms. In one example, the dashboard  16  includes a power meter  48 , fuel level gauge  50 , fuel pressure gauge  52 , load power meter  54 , load frequency  56 , and engine temperature gauge  58 . It is contemplated that the dashboard  16  may include one or more toggle buttons (not shown) to toggle the display information between various menus. Alternately, the menus could be toggled automatically. The dashboard  16  may be displayed on any device or monitor capable of electronically displaying information, such as a computer screen or the display of a mobile phone or personal data assistant. 
         [0020]    As shown in  FIGS. 1 and 2 , the various wireless modules and the dashboard  16  are equipped with antennas  60  to facilitate the transmission and reception of data in a manner that is known. Various types of known antennas may be used. 
         [0021]    Turning now to  FIG. 3 , it is contemplated that the present invention may be implemented with a hybrid load management system in which wireless and traditional wired connections are used to provide performance information to the load management controller  42 . In the hybrid arrangement  62  illustrated in  FIG. 3 , one of each type of load, e.g., one AC unit  36 , one thermostat  46 , and one large load  40 , is wired to the load management controller  42 . The other loads are associated with a wireless module as described above and communicate with wireless module  44  to transmit data to and receive commands from the load management controller  42 . 
         [0022]    It is contemplated that the controller  42  could execute one of a number of load management programs to control the loading on the generator(s) when backup power is being provided to the loads of the electrical system. For example, according to one exemplary program, the steps of which are illustrated in the flow chart  64 , each of the loads is classified based on its current draw. In this regard, the controller, after determining that the generator(s) is providing electrical power to the electrical system at block  66 , determines if the electrical system is overloading the generator(s) at block  68 . If so, all loads are disabled at block  70 . This can be done by transmitting command signals to the wireless modules and contactor modules (and wired counterparts in a fully wired or hybrid load management system) instructing the modules to electrically isolate their loads from the generator(s)  14 , such as by opening a corresponding contactor, switch, or adjusting a setting on a thermostat, for example. If an overload is not detected, all loads on the generator(s) are left enabled at block  72  and the process loops back to block  66  and repeats the steps described above. 
         [0023]    However, if an overload is detected at block  68 , the loads are disabled at block  70  as noted above. As the loads are disabled, the controller iteratively determines if the generator(s) is overloaded at block  74 . It is contemplated that the controller can stagger the disabling of the loads and capture data during the disabling process that the controller can then use when loads are reenabled. That is, the current draw on the generator(s), for example, can be read as the loads are sequentially disabled to determine the current draw each load is placing on the generator. Once each of the loads has been disabled, i.e., electrically isolated from the electrical generator(s), the controller observes a predefined delay period at block  76  to allow the output of the generator(s) to stabilize. After the delay, the controller then instructs the wireless modules and wireless contactor modules to “re-enable” the disabled loads. In a preferred embodiment, each load is classified and grouped. In this regard, after the delay is observed, the first group of loads is re-enabled. 
         [0024]    The loads can be grouped in a number of ways. For example, the loads may be grouped based on criticality, i.e., importance of the load. Medical equipment, for instance, may be deemed the most important for a given electrical system and thus placed into the first group whereas audio/video appliances may be less important and grouped accordingly. The loads could also be grouped based on current draw, or expected current draw, so that the loads that require the most current are enabled before other loads. Additional information, such as expected use during utility power outage, could be used to classify or group the loads. For example, the controller could take a reading of the thermostats for the AC units and compare that data to ambient temperature information and determine that the AC units will not be required for an extended period. Thus, while the AC units may otherwise be in the first group that is enabled, the controller may change the grouping of the AC units based on their reevaluated importance level. 
         [0025]    After the first group of loads is enabled at block  78 , the controller again determines if the generator(s) is being overloaded at block  80 . If not, another delay is observed at block  82  and the next group of loads is enabled at block  84 . Thereafter, the process loops back to block  80  until each of the loads has been enabled or an overload condition has been detected. 
         [0026]    If an overload condition is detected at block  80 , the process returns to block  70  and repeats the steps described above. In one embodiment, if an overload condition is detected subsequent to a group of loads being enabled, the controller, when re-enabling the loads of that group, enables the loads one at a time based on a priority level for each load. 
         [0027]    Once utility power is restored and the generator is deactivated, as determined at block  66 , the controller re-enables all loads at block  86 . The enabling of the loads upon restoration of utility power can be done simultaneously or in sequenced/staggered manner. 
         [0028]    It will be appreciated that the wireless modules described above can have application specific code running on them without affecting the transmission of data. This allows simple tasks to be done without the need for a separate processing unit or circuitry. The load management system can be configured with different message sizes and update rates that provide the flexibility needed to reduce current consumption for battery powered applications. 
         [0029]    Multiple wireless modules can be paired together. Pairing allows the modules to know what other modules it should communicate with. Several different modules can be paired to a single generator. This allows a generator to simultaneously have external sensors, a remote user interface, and any other available wireless features. 
         [0030]    In describing the load management systems of  FIGS. 2 and 3 , representative uses for the various wireless modules have been described. It is understood however that the wireless modules could be used to transmit or receive data different from that described herein. For example, a wireless module could be used for or with:
       Remote status monitor, e.g., dashboard  16     Remote interface that allows remote user control   Digital remote fuel monitor   Analog remote fuel monitor   Load management and load profile   Wireless load shed   Wireless air conditioner interrupter   Wireless transfer switch—transfer signal   Overload indicator   Battery voltage monitor   Communication between generators   Remote generator start/stop   Remote power bar (generator load indicator)   Sensors for generator
           Temperature   Pressure   Humidity   Wind speed/direction   Fuel Pressure   Fuel Quantity   Engine Speed   Demand   Voltage   Frequency   Accelerometer   Utility Sense   Toxic Emissions, e.g., carbon monoxide nitrous oxide, gas vapor, etc   Water sensor for house flood detection   
               
 
         [0059]    The wireless communication system of the present invention may also be used with smart load management systems that intelligently manage large loads allowing a smaller generator to meet the demands that heretofore have required larger generators. 
         [0060]    As apparent from the foregoing description, the system of the present invention can be used to manage various types of loads. For example, air conditioners typically place a large load on an electrical generator and are often one of the largest loads of a home electrical system. The wireless modules together with command signals received from a load management controller can control operation of thermostats for the AC units to interrupt the signals in the thermostat control wires to effectively disable the AC units. 
         [0061]    Other types of loads can be similarly managed. That is, the wireless module for a given load receives wireless commands from the wireless module of the generator or load management controller and when it is desired or needed to terminate the current draw of the load, a wireless signal is transmitted to the wireless module for the load instructing the module to shut-down operation of the load. Alternately, power to the load is run through a contactor module and in the event of an overload or other condition in which it is desired, the module cuts off power to the load. 
         [0062]    The system can manage multiple numbers of each type of load. The loads can be set into priority levels that determine when they are enabled after an overload. After the overload has subsided, loads may be enabled sequentially one at a time. If an overload occurs again all loads are shed. If an overload occurs shortly after adding a load, that load is assumed to be the one that is overloading the system and is locked out for a set amount of time. The other loads are allowed to run. A signal can then be provided to the wireless module for the locked out load identifying the load as being locked out. That information can then be communicated to the controller so that corresponding information can be displayed on the dashboard or otherwise communicated to a user, such as through a text or email message. 
         [0063]    It is also contemplated that the present invention may also be used with a wired load management system in which a load management controller wirelessly transmits performance and operational data to a remote user interface, such as dashboard  16 , to enable a user to remotely monitor, and control, the load management system and the components therein. For example, if the fuel level of a generator is running low, whether it be part of a wireless, hybrid, or wired system, the user could periodically disable the generator or slow it down to conserve fuel based on an expected downtime of utility power and/or until the fuel source can be replenished. 
         [0064]    Many changes and modifications could be made to the invention without departing from the spirit thereof. The scope of these changes will become apparent from the appended claims.