Patent Publication Number: US-2003224833-A1

Title: Cellular base station power generator having remote monitoring and control

Description:
BACKGROUND OF THE INVENTION  
       [0001] This invention relates to electric power generators and particularly to an electric power generator which is monitored and controlled by a remote processing system and which provides electrical power to a cellular phone base station.  
       [0002] In recent years, consumer demand for effective cellular phone service has risen dramatically. Consumers now often demand cellular phone service wherever they and their respective cellular phones happen to be located. Specifically, customers now often demand “coast-to-coast” cellular service. In order to satisfy this demand, cellular base stations must be placed and operated in various locations so that effective wireless communication (transmission and reception) can be established between a particular cellular base station and any cellular phone(s) located in the same geographic cellular area served by that particular cellular base station.  
       [0003] Some of the locations (e.g., remote rural areas) at which cellular base stations are placed will typically not have access to mains power infrastructure to supply the primary electrical power required to operate a cellular base station. In order to provide effective cellular service in these remote geographic areas, it may therefore be beneficial to provide the electrical power required by a cellular base station with an on-site electrical power generator. Moreover, even if a cellular base station receives primary electric power from the mains power infrastructure, there often remains a need for a back-up power supply in case the mains power fails.  
       [0004] If an on-site power generator is used to provide electrical power to a cellular base station located in a remote area, it would be further beneficial to maximize the amount of time between maintenance services and to have the capability to remotely monitor and control the on-site generator (i.e., monitor and control the on-site generator from a location which is remote from the onsite generator). This remote monitoring and control would help, for example, to minimize costs associated with travelling to the generator sites for maintenance service.  
       [0005] TowerPOWER® produces an electrical power generator which is capable of serving the wireless industry by providing on-site power to cellular base stations. A remote monitoring system, Site-Guard™, is now available with TowerPOWER® generators.  
       BRIEF DESCRIPTION OF THE INVENTION  
       [0006] In an exemplary embodiment of the present invention, an electrical power generator for outputting on-site electrical power comprises: an engine, an alternator operatively coupled to the engine, a controller operatively coupled to the engine and alternator for controlling at least one operational parameter relating to the engine or alternator, and a modem operatively coupled to the controller for receiving data from a remote source, the received data being processed by the controller to control the operational parameter.  
       [0007] In another exemplary embodiment of the present invention, a system comprises: a cellular base station for communicating signals with one or more cellular telephones, an electical power generator located on the site of and connected to the cellular base station. The power generator may include an engine, an alternator coupled to the engine, a controller for monitoring and controlling at least one operational parameter of the alternator or engine, and a modem for remotely communicating data relating to the operational parameter of the alternator or engine. The system further includes a processing system remotely located from the power generator and the cellular base station for communicating data with the modem.  
       [0008] In yet another exemplary embodiment of the present invention, a method of remotely controlling a power generator which provides on-site electrical power to a cellular base station comprises: receiving in a modem of the power generator data from a processing system that is remotely located from the power generator, the received data reflecting a command for controlling at least one operational parameter of an alternator or engine of the power generator, and processing the received data and controlling the operational parameter of the alternator or engine of the power generator in accordance with the received data.  
       [0009] In yet another exemplary embodiment of the invention, a method of remotely controlling first and second on-site power generators using the same processing system comprises: receiving in a first modem of the first power generator data from the processing system, the processing system being remotely located from the first power generator, the data received by the first modem reflecting a command for controlling at least one operational parameter of an alternator or engine of the first power generator; and processing the data received by the first modem and controlling the operational parameter of the alternator or engine of the first power generator in accordance with the data received by the first modem. The method further comprises receiving in a second modem of the second power generator data from the processing system, the processing system being remotely located from the second power generator, the data received by the second modem reflecting a command for controlling at least one operational parameter of an alternator or engine of the second power generator; and processing the data received by the second modem and controlling the operational parameter of the alternator or engine of the second power generator in accordance with the data received by the second modem. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0010] These, as well as other advantages of this invention, will be more completely understood and appreciated by careful study of the following more detailed description of the presently preferred exemplary embodiments of the invention taken in conjunction with the accompanying drawings, in which:  
     [0011]FIG. 1 is a diagram illustrating a cellular telephone system including at least one cellular base station which receives electrical power from a remotely controlled on-site electrical power generator in accordance with an exemplary embodiment of the present invention;  
     [0012]FIG. 2 is a high level-top view diagram of a power generator illustrated in FIG. 1 showing at least some components thereof;  
     [0013]FIG. 3 is a perspective view of a power generator for providing electrical power to a cellular base station in accordance with an exemplary embodiment of the present invention;  
     [0014]FIG. 4 is a side view of the power generator illustrated in FIG. 3;  
     [0015]FIG. 5 is a back view of the power generator illustrated in FIG. 3;  
     [0016]FIG. 6 is a perspective view of the power generator illustrated in FIG. 3 being lifted;  
     [0017]FIG. 7 is a perspective view of the power generator illustrated in FIG. 3 being moved using a pallet;  
     [0018]FIG. 8 is a top view of an exemplary engine which forms a part of the power generator in accordance with an exemplary embodiment of the invention;  
     [0019] FIGS.  9 A- 9 C are views illustrating an exemplary alternator which forms a part of the power generator in accordance with an exemplary embodiment of the invention;  
     [0020]FIG. 10 illustrates a front control panel including an exemplary controller which forms a part of the power generator in accordance with an exemplary embodiment of the present invention;  
     [0021]FIG. 11 is a more detailed view of the controller of the front control panel illustrated in FIG. 10;  
     [0022]FIG. 12 is a computer video screen display of a computer system in remote communication with the power generator representing a control panel allowing a user to review data and input commands to control the power generator in accordance with an exemplary embodiment of the invention;  
     [0023]FIG. 13 is a computer video screen display of a computer system in remote communication with the power generator allowing the user to select the language that contents of other screens will be displayed in accordance with an exemplary embodiment of the invention;  
     [0024]FIG. 14 is a computer video screen display of a computer system in remote communication with the power generator illustrating various readings of operational parameters of the power generator in accordance with an exemplary embodiment of the invention;  
     [0025]FIG. 15 is a computer video screen display of a computer system in remote communication with the power generator illustrating various input and output states of the power generator in accordance with an exemplary embodiment of the invention;  
     [0026]FIG. 16 is a computer video screen display of a computer system in remote communication with the power generator illustrating an alarm condition of the power generator in accordance with an exemplary embodiment of the invention;  
     [0027]FIG. 17 is a computer video screen display of a computer system in remote communication with the power generator which allows a user to set a day and time for a an automatic test of the power generator to be performed in accordance with an exemplary embodiment of the invention;  
     [0028]FIG. 18 is a computer video screen display of a computer system in remote communication with the power generator illustrating recorded events relating to operation of the power generator in accordance with an exemplary embodiment of the invention;  
     [0029]FIG. 19 is a computer video screen display of a computer system in remote communication with the power generator illustrating information relating to the tele-control of the power generator in accordance with an exemplary embodiment of the invention;  
     [0030]FIG. 20 is a computer video screen display of a computer system in remote communication with the power generator illustrating a settings window for a modem of the power generator in accordance with an exemplary embodiment of the invention;  
     [0031]FIG. 21 is a diagram illustrating remote communication between modems of the power generator and computer system in accordance with an exemplary embodiment of the invention;  
     [0032]FIG. 22 is a diagram illustrating remote wireless communication between a power generator having a GSM modem and a computer system or cellular telephone in accordance with an exemplary embodiment of the invention;  
     [0033]FIG. 23 is a diagram illustrating noise levels of the power generator at various load levels in accordance with an exemplary embodiment of the invention;  
     [0034]FIG. 24 is a diagram illustrating various alarm and pre-alarm connections to a controller of the power generator in accordance with an exemplary embodiment of the invention; and  
     [0035]FIG. 25 is a diagram illustrating, inter alia, an auxiliary battery which may be used to power a modem and controller of a power generator in accordance with an exemplary embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0036]FIG. 1 illustrates a cellular frequency telephone system including a number of cellular base stations  30  each operatively connected to a respective base station control  33 . Each cellular base station  30  is located within a respective geographic cellular area and communicates with a central office commonly referred to as a mobile telephone switching office (MTSO) through a base station control  33 . The MTSO makes the necessary connections to enable wireless cellular communication between a cellular base station  30  and any cellular telephones  31  located within the same cellular area and communicates signals to/from a channel on the public switched telephone network (PSTN).  
     [0037] Each of the cellular base stations  30  receives electrical power from a respective on-site electrical power generator  10 . It will be understood, however, that not every cellular base station  30  must necessarily receive primary power from an on-site power generator. For example, the cellular base station located in cellular areas A and B may receive primary electrical power from an electrical mains infrastructure, while the cellular base stations in cellular areas C and D may receive primary power from respective on-site power generators  10 . Any cellular base station that receives primary power from an electrical mains infrastructure may still be operatively connected to a power generator  10  for emergency back-up power. Switches may be used to disconnect the electrical mains power when power generator  10  is switched to connect to the cellular base station. The on-site power generator  10  may thus serve as the primary or secondary source of power to a cellular base station in accordance with an exemplary embodiment of the invention. Cellular base stations located in geographic areas (e.g., rural areas) in which connection to an electrical mains infrastructure is not available may therefore become operable by receiving highly reliable (i.e., limited downtime) electrical power from an on-site power generator  10 , thereby helping to satisfy consumer demand for effective cellular phone service over the widest possible geographic region. Highly reliable power to base stations connected to electrical mains power may be ensured through back-up power provided by generator  10 .  
     [0038] Each power generator  10  may be monitored, operated and controlled by a processing system  20  (e.g., a computer system having a modem or a cellular telephone) which is remotely located from the power generator  10  and the base station  30 . A location that is “remote” from the power generator is one that is at the very least located off-site from the generator. For example, a cellular base station located in cellular area B is “remote” from the power generator and its connected cellular base station located in cellular area A (see FIG. 1).  
     [0039] The power generator  10  and the processing system  20  remotely communicate with each other so that operational parameters of the power generator (e.g., readings, measurements, input/output status, failures, test results, alarms of the power generator) can be remotely reported from the power generator  10  to the processing system  20  for review and evaluation by a user (e.g., power generator technician) and control commands and/or inquires input by the user (e.g., start/stop the power generator, change an operation parameter such as temperature, pressure, voltage, etc.) may be transmitted from processing system  20  to power generator  10  for processing and implementation by the power generator  10 .  
     [0040] While FIG. 1 illustrates an exemplary embodiment in which each of power generators  10  remotely communicates with the same processing system  20 , the embodiment can be altered so that at least one power generator  10  communicates with another processing system  20 . For example, each power generator  10  may be configured (e.g., using communication having different respective frequencies) to remotely communicate with its own separate processing system  20 . By enabling remote control of a power generator, a technician may reduce his/her amount of travel to each generator site and still provide effective monitoring and predictive and preventative maintenance control. Furthermore, if one processing system remotely communicates with a plurality of generator sites, a large amount of data may be made available to a highly trained specialist at processing system  20 . The specialist may in turn provide any necessary control commands to one or more of the generators.  
     [0041] Referring to FIG. 2, the power generator  10  includes, inter alia, an engine (e.g., a diesel engine)  101 , an alternator  103 , a controller  105  and a modem  107  (e.g., analog modem, GSM modem or internet connection), auxiliary battery  109 , air intake vents  111 , air outlet vents  113 , fuel inlet  117  for receiving fuel from an external fuel tank, exhaust outlet manifold  115 , and load bank  118 . Controller  105  is operatively connected to engine  101  and alternator  103  and to modem  107 . Controller  105  provides/receives signals to/from the engine  101  and alternator  103  and may process any received signals for transmission to the remotely located processing system  20  through modem  107 . The signals received by controller  105  from the engine  101  and/or alternator  103  may reflect operational parameters such as readings, measurements, status, test results, alarms relating to, for example, the engine&#39;s and/or alternator&#39;s temperature, engine&#39;s oil pressure, engine&#39;s fuel level, battery voltage level, charger failure, engine and/or alternator stoppage, running or starting status of the generator, mains voltage, generator&#39;s output voltage, frequency or current level, status (open/closed) of any engine or alternator switch, engine exhaust level, date/time of any conducted test, emergency stoppage, mode of operation, results of load test, etc. The controller is also capable of receiving, processing and remotely transmitting signals from other sensors of the power generator such as sensors indicating the opened/closed status of control panel door  119  (see FIG. 4) or top hatch door  121  (see FIGS.  4 - 6 ). These signals may protect generator  10  against theft, vandalism or sabotage.  
     [0042] Controller  105  may receive and process remote commands or inquiries from processing system  20  through modem  107 . These commands and/or inquiries may be initiated by processing system  20  or may be received in response to a previous transmission from controller  105 . After processing received commands and/or inquiries, the controller  105  may control (e.g., change, test, detect or measure) an operation parameter (e.g., any of the operational parameter(s) of the engine and alternator noted above) of power generator  10 .  
     [0043] Referring to FIGS.  2 - 7 , an exemplary embodiment of power generator  10  includes a chassis of electrically welded steel for enclosing and protecting, inter alia, engine  101 , alternator  103 , controller  105 , modem  107  and auxiliary battery  109 . Vibration absorbers (not shown) may be placed between (a) the engine  101  and alternator  103  and (b) the chassis, and a drip tray may be connected to a sub-base waste tank of the generator.  
     [0044] The relatively small unit size (length×height×width of 1800×890×950 mm) and weight (approx. 550 kg) of power generator  10  allows it to be easily transported by lifting it using handling rings  123  (see FIG. 6) or moving it with a pallet (see FIG. 7) and quickly installed at the generator site. The relatively easy transport and installation of power generator  10  is particularly beneficial when the terrain leading to or at the generator site is rough.  
     [0045] General technical specifications of an exemplary embodiment of power generator  10  may include the following:  
     [0046] Limited Time Power (L.T.P.)=10 kVA cost=1  
     [0047] Continuous Operating Power (C.O.P.)=9 kVA cosp=1  
     [0048] Voltage=230 V single-phase  
     [0049] Amperage=43.5 A  
     [0050] Frequency=50 Hz  
     [0051] Rotational speed=1500 rpm  
     [0052] Fuel type=automotive diesel fuel  
     [0053] Engine mfg.=Lombardini  
     [0054] Engine model=LDW CHD 1503  
     [0055] Engine max power at 1500 rpm=13.5 kW  
     [0056] Engine displacement=1551 cc  
     [0057] Cylinders=3  
     [0058] Cooling system=water  
     [0059] Alternator mfg.=Meccalte  
     [0060] Alternator model=ECO 28 S/4  
     [0061] Alternator type=4 poles brushless with avr  
     [0062] Dimensions (1×w×h)=1800×890×950 mm  
     [0063] Sound level @ 7 m (75% C.O.P. rating)=&lt;70 dBa  
     [0064] Dry weight (kg.)=approximately 550 kg  
     [0065] Protection=IP 33.  
     [0066]FIG. 8 illustrates an exemplary engine  101  that may be utilized as part of power generator  10 . The engine may be, for example, a diesel powered engine and may include an enlarged lube oil sump  1011  (e.g., at least  11  liters) and fuel tank to extend the time between maintenance inspections/services. Specifically, the enlarged oil sump  1011  and fuel tank of an exemplary embodiment of the invention provides a time interval of six weeks between maintenance services. This interval may be maintained or even further increased through the use of an automatic lube oil top up tank.  
     [0067] Technical specifications of an exemplary engine  101  that may be used as part of generator  10  may include the following:  
     [0068] Make=Lombardini  
     [0069] Type=LDW CHD 1503  
     [0070] Rotation speed=1,500 r.p.m.  
     [0071] Maximum power=13.5 kW at 1,500 r.p.m.  
     [0072] Cycle of the engine=4-cycles  
     [0073] Type of injection=IDI  
     [0074] Number and configuration of cylinders=3 in line  
     [0075] Bore=88 mm  
     [0076] Stroke=85 mm  
     [0077] Valve system=maintenance free hydraulic valve lifters  
     [0078] Mean linear piston speed=4.25 m/s  
     [0079] Displacement=1.55 liters  
     [0080] Type of cooling=water  
     [0081] Fuel consumption  
     [0082] at full load=4.6 liters/hour  
     [0083] at ½ load=2.5 liters/hour  
     [0084] at ¼ load=1.2 liters/hour  
     [0085] Oil consumption=0.006 liters/hour  
     [0086] Exhaust gas emission: =per directive 97/68 EEC phase 2  
     [0087] Climatic Conditions of Engine  
     [0088] ambient temperature:  
     [0089] max: 50° C.  
     [0090] min: −20° C.  
     [0091] derating: −2% for every 5° C.  
     [0092] above 20° C.  
     [0093] relative humidity: max: 90%  
     [0094] altitude: engine rated power is at sea level derating: −1% for every 100 m above sea level  
     [0095] Characteristics of Engine Liquids  
     [0096] Fuel: standard automotive diesel fuel  
     [0097] Oil: API—CD  
     [0098] Grade:  
     [0099] ambient 20° C. to 50° C.: SAE 40  
     [0100] ambient 0° C. to 20° C.: SAE 20  
     [0101] ambient −20° C. to 0° C.: SAE 10  
     [0102] Coolant: Mixture:  
     [0103] 50% ethylene glycol antifreeze  
     [0104] 50% demineralized water  
     [0105] Cooling of Engine  
     [0106] maximum ambient temperature: 50° C.  
     [0107] fan driven by water pump—alternator belt  
     [0108] high-temperature water alarm  
     [0109] low water level alarm  
     [0110] thermostatic valve  
     [0111] Preheating of Engine  
     [0112] as IDI the engine is glow-plugs equipped for low temperature easy starting  
     [0113] Starter of Engine  
     [0114] electrical 12 Volt starter on the gear ring of the engine&#39;s flywheel  
     [0115] 12 Volt lead battery with a capacity of 80 Ah  
     [0116] Speed Regulation of Engine  
     [0117] type: mechanical (engine integrated)  
     [0118] rate of regulation under established conditions: ±3  
     [0119] Exhaust of Engine  
     [0120] primary muffler inside the enclosure  
     [0121] final outside protected super quiet muffler  
     [0122] Coupling of Engine  
     [0123] semi-rigid coupling by flanged mounting on single-bearing alternator  
     [0124] Lubrication of Engine  
     [0125] spin-on cartridge oil filter— 
     [0126] 12.7 liters total capacity oil sump  
     [0127] 11.7 liters total oil volume before low pressure alarm  
     [0128] oil level warning when oil volume is 2.1 liters before low pressure alarm  
     [0129] manual drain pump  
     [0130] Air Intake of Engine  
     [0131] cartridge-type dry air filter  
     [0132] Fuel of Engine  
     [0133] 10 micron spin-on cartridge primary fuel filter with:  
     [0134] water separation system  
     [0135] transparent bowl for visual water checking  
     [0136] electrical detection of water and warning  
     [0137] 3 micron spin-on cartridge final fuel filter  
     [0138] electro-valve on the fuel circuit for:  
     [0139] stopping the engine normally stopping when a safety device has tripped  
     [0140] mechanical lift pump up to 1.5 m head  
     [0141] fuel system provided for external sub-base tank  
     [0142] Sensors of Engine  
     [0143] low engine oil pressure (alarm)  
     [0144] low oil level in the sump (warning)  
     [0145] engine cooling high water temperature (alarm)  
     [0146] approaching engine cooling high water temperature (warning)  
     [0147] engine cooling circuit low water level (alarm)  
     [0148] Service and Maintenance Intervals of Engine  
     [0149] 1000 h:  
     [0150] oil replacement  
     [0151] oil filter replacement  
     [0152] primary and final fuel filter replacement  
     [0153] fan belt check  
     [0154] air filter check  
     [0155] 2000 h:  
     [0156] fan belt replacement  
     [0157] air filter replacement  
     [0158] In order to enable power generator  10  to generate the necessary electric power to operate a cellular base station, engine  101  drives a rotor of alternator  103  within its stator under the monitoring and control of controller  105 . The electrical output of the alternator may then be transformed as necessary for application to the cellular base station.  
     [0159] FIGS.  9 A- 9 C illustrate an exemplary alternator  103  with exemplary dimensions including fan  1031 , main rotor  1032 , exciter rotor  1033  and shaft  1034 . Technical specifications of an exemplary alternator  103  that may be used as part of generator  10  may include the following:  
     [0160] General Description of Alternator  
     [0161] make=Meccalte  
     [0162] type=ECO 28 S/4  
     [0163] rotation speed=1,500 r.p.m.  
     [0164] poles=4  
     [0165] rated power  
     [0166] =16 kVA @ H class 3 ph 400V 50 Hz PF=0.8  
     [0167] =10.5 kVA @ H class 1 ph 230V 50 Hz PF=1  
     [0168] type of connection=Delta connection single phase 230V rated voltage  
     [0169] ECO  4  pole alternators may be brushless, self-regulating and incorporate a rotating inductor with damper cage winding and a fixed stator with skewed slots. The stator windings may have a shortened pitch to reduce the harmonic content of the output waveform.  
     [0170] The casing of the alternator may be made of steel, the shields of cast iron, and the shaft of C45 steel. The shaft may have a keyed fan. All rotating components may be epoxy resin impregnated, and higher voltage parts such as the stators may be vacuum-treated.  
     Electrical Characteristics of the Alternator (@50 hz 230/400v)  
     [0171] Regulation with SR7/2=+1.5% with any power factor and speed variations between −5% +30%  
     [0172] Efficiencies (class F 15 kVA 3 ph)= 
     [0173] 4/4% 83.3  
     [0174] 3/4% 84  
     [0175] 2/4% 83  
     [0176] 1/4% 81.4  
     [0177] Reactances (class F 15 kVA 3 ph)  
     [0178] Xd % 196  
     [0179] Xd′ % 16.9  
     [0180] Xd″ % 11.5  
     [0181] Xq % 72  
     [0182] Xq′ % 72  
     [0183] Xq″ % 24  
     [0184] X2% 17  
     [0185] X0%  3 . 6   
     [0186] Short Circuit Ratio=Kcc 0.67  
     [0187] Time Constants= 
     [0188] Td′ sec. 0.051  
     [0189] Td″ sec.=0.018  
     [0190] Tdo′ sec.=0.90  
     [0191] Ta sec.  0 . 016   
     [0192] Short Circuit Current Capacity=% &gt;300  
     [0193] Excitation at no load Amp.=0.5  
     [0194] Excitation at full load Amp.=1.7  
     [0195] Overload (long-term)=1 hour in a 6 hours period 110% rated load  
     [0196] Overload per 20 sec.=% 300.  
     [0197] Stator Winding Resistance (20° C.)=Ω0.424  
     [0198] Rotor Winding Resistance (20° C.)=Ω1.26  
     [0199] Exciter Resistance (20° C.)= 
     [0200] Ω Rotor: 0.640  
     [0201] Stator: 10.60  
     [0202] Heat dissipation at f.l.cl.F=2406 W  
     [0203] Telephone Interference THF=&lt;2% TIF&lt;45  
     [0204] Radio interference=VDE 0875 N.  
     [0205] Waveform Distors.(THD) at f. load LL/LN=% 2/2  
     [0206] Waveform Distors.(THD) at no load LL/LN=% 3.7/3.7  
     [0207] Mechanical Characteristics of Alternator  
     [0208] Protection=IP 23 M  
     [0209] DE bearing=6309-2RS  
     [0210] NDE bearing=6207-2RS  
     [0211] Weight of wound stator assembly=kg 33.2  
     [0212] Weight of wound rotor assembly=kg 18  
     [0213] Weight of complete generator=kg 108  
     [0214] Maximum overspeed=rpm 2250  
     [0215] Unbalanced magnetic pull at f.l.cl.F=kN/mm 3  
     [0216] Cooling air requirement=m 3 /min 5.3  
     [0217] Inertia Constant (H) sec.=0.08  
     [0218] Noise level at 1 m/7 m=dB(A) 68/57  
     [0219] AVR Protections of Alternator  
     [0220] SR7 regulators may be provided with an under-speed protection with an intervention threshold which can be adjusted by the potentiometer marked “Hz”. This protection intervenes instantaneously by reducing the alternator voltage to a safe value when the frequency falls below 10% of the nominal value. These regulators may also have inherent overload protection which senses the exciter field voltage value. Should this field voltage value exceed the nominal value for a period of more than 20 seconds, then the alternator voltage is automatically reduced to a safe operating level. This overload function has a built-in delay to allow for the overload when starting motors (normally 5-10 seconds). The operating threshold of this protection device is adjustable by the potentiometer marked “AMP”.  
     [0221]FIG. 10 illustrates a controller panel  1051  including a front panel of controller  105  (also labeled “TE803 CONTROLLER”), controller fuse  1052 , voltage potentiometer  1053 , main switch  1054 , ammeter  1055 , load bank controls  1056 , internal terminal board  1057 , siren  1058  and internal relays  1059 . As discussed above, controller  105  enables power generator  10  to be remotely monitored by a user at processing system  20  through data transmitted from controller  105  through modem  107 . Controller  105  also allows power generator  10  to be remotely controlled through data signals received from processing system  20 . However, in addition to this remote control, controller  105  also allows power generator  10  to be manually controlled on-site through control buttons/switches  1062 - 1069 ,  1041 - 1042  (FIG. 11) provided on the front panel of controller  105 . The front panel of controller  105  also displays results of any reading, measurement, test, alarm, etc. relating to an operational parameter of the power generator on display  1061  and/or other LEDs. As discussed above, data reflecting the results may also be transmitted to processing system  20 . Input can be provided at processing system  20  or at the control panel of controller  105  to determine whether on-site input at the control panel  1051  or remote input at processing system  20  is given precedence over the other for a given time. The front panel of controller  105  may be accessed by a technician by unlocking and opening door  119  (FIG. 2).  
     [0222] Technical specifications and characteristics of an exemplary controller  105  which forms a part of generator  10  may include the following:  
     Controller Main Features  
     [0223] Control based on 11 MHz Intel 80c552 microprocessors.  
     [0224] 32 Kbyte EPROM memory program  
     [0225] 32 Kbyte static RAM data memory  
     [0226] 512 Word EPROM nonvolatile data memory  
     [0227] Operator display of 3 figures LED display  
     [0228] Function/State/Alarm display by means of 15 LED&#39;s  
     [0229] Diaphragm button strip with 7 mechanical effect buttons  
     [0230] Voltages measure at real effective value (RMS.)  
     [0231] All programming options accessible from the frontal side without dip switch (by software in permanent memory)  
     [0232] Programming options protected by admittance key  
     [0233] “Intelligent” modulation of voltage and current control of battery charger  
     [0234] RS 232 serial interface for remote control by computer or modem  
     [0235] Description of Panel of Controller  
     [0236] Reset/Manual/Auto/Test buttons  1069 ,  1066 ,  1068 ,  1065  (see FIG. 11) (to select operating procedures)  
     [0237] Measure button  1063  (to select display)  
     [0238] Start/Stop buttons  1062 ,  1064  (to start/stop the generator)  
     [0239] Reset/Man/Auto/Test LED (selected operating procedure signals)  
     [0240] LED volt, hertz, V. Battery, hour meter (selected measure signals)  
     [0241] LED battery (battery charger condition)  
     [0242] LED starting failure (Generator starting failure)  
     [0243] LED engine on (Generator on)  
     [0244] LED alarms (alarms on)  
     [0245] LED TLR (utility mains), TLG (Generator AC power leads) indicates power source being delivered to the load  
     [0246] LED failure (fault/alarm signal)  
     [0247] 3 figure display  1061  (display of measures, alarms, etc.)  
     [0248] Terms and Procedures of the Controller  
     [0249] PROGRAMMING: Programming is the set up of the controller. This is done before or during the installation of the generator. All operating times and calculations that affect the system functioning can be set up and the parameters may be stored in a permanent memory. Only authorized trained personnel can reach this password protected function. “Options” (another type of parameters), on the contrary, can be adjusted at any time without a password.  
     [0250] STARTING CYCLE: The sequence of generator starting is as follows: First glow-plugs are energized (programmable duration), then the fuel solenoid valve is activated. After these two steps, the control panel enters into a start interval (programmable duration) alternating with intervals of cool down (programmable duration). Once the engine is on, the starting attempts stop immediately. The siren relay is activated before starting up the engine (due to an automatic start—test or to an external start). This will help maintenance technicians realize that the group is going to be started.  
     [0251] GENERATOR STOPPING PROCEDURE: The transfer switch (if present) opens and the generator continues to run for a programmable cool down period at the end of which a fuel solenoid valve opens and the engine stops. In case of an emergency stoppage, the above mentioned procedure takes place without considering the cool down time.  
     [0252] ENGINE ON: The engine is on when the “engine ON” signal, which comes out of the engine alternator exceeds the fixed voltage or programmed value. Its LED shows the engine-on signal.  
     [0253] ALARMS ON: Oil pressure and high temperature alarms are connected after a delay time (programmable) greater than the engine-on signal time. To stress that, the “engine ON” LED becomes flashing when the engine is on but the alarms are not enabled, and becomes steadily lit (on) when the engine is running and the alarms are enabled. During the stopping cycle, the alarm is disabled and the fuel solenoid valve simultaneously closes.  
     [0254] GENERATOR-ON: The generator-on signal occurs when the generator voltage is not out of the fixed limits (lower than the minimum fixed voltage or higher than the maximum fixed voltage) and remains in that state for a programmable time.  
     [0255] UTILITY/GENERATOR AND GENERATOR/UTILITY SWITCHING: In case of mains utility presence (i.e., in case both a mains power and an on-site generator  10  may be utilized to power the cellular base station), the remote control switches between the utility and generator. A delay time occurs to avoid simultaneous connections.  
     [0256] Description of Display of Controller  
     [0257] The following measures can be selected on the display  1061  (FIG. 11):  
     [0258] Utility/Generator voltage (Volt)  
     [0259] Frequency of Generator signal (Hertz)  
     [0260] Battery voltage (Vdc)  
     [0261] Generator working hours (hour meter)  
     [0262] A light also signals which measurement is being displayed (AC volts, frequency (Hertz), Battery Vdc, run hours). Another measure on the display may be selected by pressing the measure button  1063 . When a technician selects a voltage measure and the generator is off, display  1061  will show a utility voltage. The displayed value of utility and generator voltage is in 1 volt increments, the frequency at 0.1 Hz, the battery voltage at 0.1 volt and working hours at 1 hour (even if the internal time stored is measured in minutes). The controller may display RMS voltage measurements and at the same time, accurately and quickly control all functions needed for the proper operation of the generator.  
     [0263] Operating Procedures of Controller  
     [0264] Controller  105  may perform  4  different functions: reset, automatic, manual and test (described in detail below). After a procedure is selected, its button and its corresponding LED lights up. It may be possible to skip from one operating procedure to another. After controller power-up, the operating procedure may become RESET. When one of the four operating procedures&#39; (reset, automatic, manual, test) corresponding LED is flashing, the unit is being controlled by remote control.  
     [0265] RESET PROCEDURE: When using the reset operating procedure, the controls are not operational. All displayed alarms may be set to zero as if the unit was not connected. Only the general alarm is still in operation. Control entries and the siren alarm are disconnected as well. Signaling LED&#39;s, on the contrary, remain in operation and can show measures and alarms. When Man/Auto/Test is changed to reset and the generator is in operation, the controller may stop the generator automatically without waiting for the cooling interval.  
     [0266] AUTOMATIC PROCEDURE: In the sutomatic procedure mode, the generator starts when the utility voltage goes out of limits and its respective control switch is off. After a programmed delay, utility remote control switch is switched off and the generator start cycle begins. When the generator is running and its voltage reaches the fixed limits, the generator remote control switch closes. The generator continues working until the utility voltage is restored. Once the utilities are back, the remote control switches exchange position and the generator carries out the stop cycle. When the generator is running, however, it can be stopped by means of the stop button  1062 . In the automatic procedure mode, both the remote start and stop are enabled.  
     [0267] MANUAL PROCEDURE: In the manual procedure mode, the generator can be started or stopped simply by pushing the respective start and stop buttons  1064 ,  1062  (FIG. 11). Start button  1064  begins the start cycle while stop button  1062  begins the stop cycle. After pushing stop button  1062 , the stop cycle can be stopped from beginning by immediately pushing start button  1064 . By pressing (and holding) the manual button  1066  and the TLG (generator) button  1041 , a technician can switch power from utility (mains) power to generator power. Power can be switched from generator to utility (mains) power by pressing and holding manual button  1066  and TLR (Utility) button  1042 . From one button pressing command to another, an interval delay takes place as previously programmed. Passing from auto to test or manual does not affect the operation of the generator.  
     [0268] TEST PROCEDURE: In the test procedure mode, the generator begins the start cycle. If the utility (mains) power drops out while the generator is in a test mode, the controller will override this function and switch the generator to the load. Once the utility voltage returns, the load will stay on the generator. If the auto mode is enabled, the controller will transfer the load to the utility and will start the stop cycle of the generator.  
     [0269] AUTOMATIC TEST PROCEDURE: The automatic test procedure is a periodic check that is performed by the control panel at fixed intervals (interval can be fixed during option setup). If the control panel is in automatic mode and the automatic test has been enabled, the generator runs for a fixed period before it stops.  
     [0270] WORKING HOUR CALCULATION: After the engine has started, the working minutes are counted. The calculation, expressed in hours, can be shown on display  1061 . The calculation continues even if the electrical input is disconnected and cannot be set to zero by the user.  
     [0271] PERIODIC MAINTENANCE INTERVAL: Through set up, a periodic maintenance interval, expressed in hours, is set. When the number of working minutes reaches the fixed amount, the display shows the code of maintenance request. The control panel, however, continues to work normally. Pushing reset button  1069  allows the calculation to be set to zero and the message disappears.  
     [0272] Description of Alarms Provided by Controller  
     [0273] Display  1061  and other LEDs (FIG. 11) of controller  105  may show certain codes to signal an emergency or other specific situation to an on-site technician. Additionally or alternatively, data reflecting the emergency or other situation may be remotely transmitted by controller  105  to processing system  20  via modem  107 . A technician at processing system  20  may them review the data off-site from generator  10  and then, if necessary, input instructions into processing system  20  for transmission back to controller  105  through modem  107 . Controller  105  may then process these received signals and modify an operational parameter of generator  10  accordingly. The message that is displayed on display  1061  and/or transmitted to processing system  20  disappears only when the emergency condition or situation has disappeared and the user has pressed the reset button  1069  or transmitted a reset command from processing system  20 .  
     [0274] The following codes may be displayed by the panel of the controller  105  and/or transmitted to the processing system for display:  
     [0275] A01 Temperature Alarm:  
     [0276] The temperature alarm message appears when, during engine operation, the temperature sensor detects an over temperature condition. In this case the generator remote control switch opens and the generator stops at once.  
     [0277] A02 Oil Pressure Alarm:  
     [0278] The oil pressure alarm operates like the temperature alarm mentioned above, but it refers to the sensor for insufficient oil pressure.  
     [0279] A03 Charger Alternator Failure Alarm:  
     [0280] The charger alternator failure alarm appears when the generator is running and the generator voltage is within limits, but the battery charger alternator signal is missing (lower than setup −06 for more than setup −14 time delay).  
     [0281] A04 Mechanical Alarm  
     [0282] The mechanical alarm indicates that the engine is not operating for a non-electrical problem.  
     [0283] A05 Request for Maintenance  
     [0284] This request for maintenance alarm occurs when the periodic maintenance interval has been exceeded. This interval (in hours) is programmed in the setup menu. The generator, however, continues to work normally.  
     [0285] A06 Runaway Speed Alarm  
     [0286] The runaway speed alarm occurs when frequency (Engine RPMs) exceeds the value fixed by setup. The transfer switch opens and the generator stops immediately.  
     [0287] A07 Fuel Alarm  
     [0288] The fuel alarm indicates low fuel level.  
     [0289] A08 Door Interlocks  
     [0290] The door interlocks indicator signals that one of the generator doors (e.g., doors  119 ,  121 ) has been opened. This may be programmed as an indication only.  
     [0291] A09 Prealarms  
     [0292] The prealarm indicates that one of the controlled parameters is going to alarm condition. This may be programmed as indication only.  
     [0293] A10 Starting Failure  
     [0294] An occurrence of starting failure is displayed when the number of starting attempts are performed and the engine is not yet running.  
     [0295] A11 Generator Under Frequency  
     [0296] The generator under frequency code activates when, with the alarms on (the motor running for longer than the alarm delay) the generator frequency is less than the minimum frequency alarm threshold that lasts longer than the generator voltage absence delay.  
     [0297] A12 Low Battery Voltage  
     [0298] The low battery alarm is displayed when battery voltage is below the low battery voltage alarm threshold.  
     [0299] A13 High Battery Voltage  
     [0300] The high battery alarm is activated when the battery voltage increases over the maximum battery voltage alarm threshold.  
     [0301] E01 Emergency Stop  
     [0302] The emergency stop message is displayed when the technician stops the generator by pushing the stop button or the emergency stop button in automatic or test procedures.  
     [0303] E04 Generator Voltage Failure  
     [0304] The generator voltage failure alarm occurs when, with engine running, the generator voltage goes out of the programmed voltage and time limits.  
     [0305]FIG. 24 illustrates exemplary alarm and pre-alarm connections to controller  105 . The connections of alarms and pre-alarms to controller  105  may include the following:  
     [0306] Water Temperature Alarm  
     [0307] Oil Pressure Alarm  
     [0308] Charger Alternator Failure Alarm  
     [0309] Mechanical Failure  
     [0310] Request for Maintenance  
     [0311] Runaway Speed Alarm (over speed)  
     [0312] Fuel Level  
     [0313] Low Water Level  
     [0314] Start Failure  
     [0315] Min. Frequency  
     [0316] Min. Battery Voltage  
     [0317] Max. Battery Voltage  
     [0318] Emergency Stopping On  
     [0319] Generator Voltage Failure (out of limits)  
     [0320] Approaching water temperature (pre-alarm)  
     [0321] Approaching low oil level (pre-alarm)  
     [0322] Water presence in diesel fuel (pre-alarm)  
     [0323] The activation of one of the above 3 pre-alarms initiates a call by controller  105  through modem  107  for the service. In this way, technicians can operate on the generator on time and avoid failures.  
     Description of Exemplary Technical Features of Controller  
     [0324] Supply Circuit  
     [0325] Battery Supply (US)=12 Vdc  
     [0326] Maximum Current Consumption=160 mA (250 mA with rs485)  
     [0327] Stand-by Current=110 mA (250 mA with rs485)  
     [0328] Operating Range=12V 6.2-16.5 Vdc  
     [0329] Immunity Time for Micro breaking=−150 ms  
     [0330] Maximum Ripple=10%  
     [0331] Mains Voltage Control Circuit  
     [0332] Rated Voltage (UE)=100-480 VAC  
     [0333] Operating Range=60 Hz  
     [0334] Rated Frequency (Keyboard Adjusted)=0.7-1 UE  
     [0335] Minimum Voltage Tripping (Keyboard Adjusted)=1-1.5 UE  
     [0336] Generator Voltage Control Circuit  
     [0337] Rated Voltage (UE)=100-480 Vac  
     [0338] Operating Range=70-624 Vac  
     [0339] Rated Frequency (Keyboard Adjusted)=60 Hz  
     [0340] Minimum Voltage Tripping (Keyboard Adjusted)=0.7-1 UE  
     [0341] Maximum Voltage Tripping (Keyboard Adjusted)=1-1.5 UE  
     [0342] Started Engine Control Circuit  
     [0343] Battery Charger Permanent Magnet Alternator=0-40 Vac  
     [0344] Operating Engine=6-30 Vac  
     [0345] Battery Charger Energized Alternator  
     [0346] Operating Range=0-40 Vdc  
     [0347] Adjustment Range=6-30 Vdc  
     [0348] Circuit Voltage=12 Vdc Battery  
     [0349] Output Relay Contacts to Exclude Mains and Generator: −Common Alarm Relay (Fault Relay) 1 NO/NC Contact (SPDT).  
     [0350] As illustrated in FIG. 2, generator  10  includes a load bank  118 . In order to avoid carbon deposits inside the exhaust manifold  115  on the engine in case of continuous no load or almost no load operation, the load bank  118  has been designed to automatically load generator  10  with for example a 5 kW ventilated resistive load for 15 minutes every 3 hours when the output is less then 4 kW. When the requested load is more than 4 kW the load bank is automatically disconnected. Accordingly, load bank  118  may be connected/disconnected to receive an output originating from alternator  103  to impose a load on generator  10 . Load bank  118  may be formed by, for example, one or more heaters, and may be controlled through load bank controls  1056  (FIG. 10). Data related to the automatic loading by load bank  118  may be transmitted to processing system  20 .  
     [0351] As discussed above and with further reference to FIGS.  21 - 22 , controller  105  can remotely communicate data signals relating to operational characteristics of the power generator  10  through modem  107 . Modem  107  may be formed by, for example, a modem  107   a  (see “ART 1571806” in FIG. 21) or a GSM modem  107   b  (FIG. 22). Processor system  20 , which communicates with controller  105  via modem  107 , may be formed over, for example, a computer system  20   a  including modem  21  (FIGS.  21 - 22 ) or a cellular telephone  20   b  (FIG. 22). Communication between modems  107   a  and  21  may be established on-line by, for example, a LAN or WAN such as the internet. The GSM modem  107   b  is capable of wireless transmission/reception of data to/from processing system  20  (e.g., computer system  20   a  or cellular phone  20   b ).  
     [0352] The computer system  20   a , as an exemplary processing system  20 , is capable or generating video screens to allow a computer user to review data (e.g., readings, measurements, test results, alarms, etc.) relating to operation of the power generator and to input commands and/or inquiries for transmission to the controller  105 . FIGS.  12 - 20  illustrate exemplary screens (i.e., on-line windows) that may be displayed by the computer system  20   a  so that a user can perform on-line monitoring, evaluation and control of power generator  10 . Screens for data display and command/inquiry input may be similarly provided by the display screen of cellular phone  20   b.    
     [0353]FIG. 12 illustrates an image of a video screen that closely resembles the front panel of controller  105 . Since this image closely resembles the front panel of controller  105 , a technician who is familiar with controlling the generator on-site using the front panel of controller  105  can easily become familiar with controlling the generator using the computer system  20   a  (or vice versa). A user at the computer system  20   a  can review data and input commands through the a mouse or keyboard. For example, a user may input commands to: start the generator, stop the generator, run a test, exchange/switch a contact, initiate a measurement, or sense signs of alarm and emergency.  
     [0354]FIG. 13 is a video screen that may be displayed by computer system  20   a  which allows a user to select in which language other screens are to be presented.  
     [0355]FIG. 14 is a video screen that may be displayed by computer system  20   a  which allows a user to visualize and read measurements such as mains voltage, generator voltage, generator frequency, generator voltage, battery charger alternator voltage, battery voltage, working hours and maintenance intervals. As discussed above the data illustrated by the video screen may be remotely received by the computer system  20   a  through modem  21 .  
     [0356]FIG. 15 is a video screen that may be displayed by computer system  20   a  which allows a user to visualize generator input states (e.g., high temperature, oil pressure, external start, external stop, emergency stop, low fuel level, user alarm) and output states (e.g., mains relay, generator relay, fuel valve, start, acoustic alarm, stop magnet, common alarm) that are active. Detailed information regarding a particular input or output parameter state may be obtained upon selection thereof.  
     [0357]FIG. 16 is a video screen that may be displayed by computer system  20   a  which allows a user to view an alarm. For example, FIG. 16 illustrates a low oil pressure alarm which caused the generator to stop.  
     [0358]FIG. 17 is a video screen that may be displayed by computer system  20   a  which allows a user to set a day and time for a test to begin.  
     [0359]FIG. 18 is a video screen that may be displayed by computer system  20   a  which allows a user to review a log of the latest events (e.g., the last 255 events) relating to the power generator operation that have been recorded along with their corresponding date and time. Changes made by the user, including passage from manual to automatic operation, may be recorded.  
     [0360]FIG. 19 is a video screen that may be displayed by computer system  20   a  which allows a user to view events reflecting communications between generator  10  and computer system  20   a . For example, when the control by computer system  20   a  is activated, a user will see only the bar that indicates call waiting (see FIG. 19) on the computer screen. When any generating set (furnished with the processing system and/or controller) shows an anomaly or goes into programmed maintenance, a screen will appear which indicates (from left to right on the computer video screen of FIG. 19): “Nr”=indicates the progressive number of calls, “Date”=date of the call, “Time”=time of the call, “Incoming call from”=gives the name of the generator that sends the call, “RGAMTE status”=gives the reason for the call, “User ack”=indicates if the call has already been responded to or if it must be responded to, “Call back phone number”=Telephone number of the modem for the generator.  
     [0361] Controller  105  may communicate with the processing system  20  in two different ways: (1) using an analog modem (e.g., U.S. Robotics) or (2) using a GSM modem. Using an analog modem, transmission of the data may be communicated using a normal telephone line. Using a GSM modem  107   b  (e.g., FALCOM), normal SIM CARDS can be used (rechargeable cards too) and wireless data transmission/reception may be performed in the form of SMS messages. This GSM system may enable data transmission even with a weak signal. The advantages of the GSM modem may include: (i) In case of alarm, the generator calls two mobile numbers, (ii) The alarm and measurements of the generator may be displayed directly on the computer screen  20   a  or mobile phone&#39;s screen  20   b , (iii) The generator can be controlled directly by the mobile phone without the use of a PC. It is enough to send an SMS message to the board. After having followed the command (start, stop, etc.) the generator sends a message to the mobile giving all of the measurements and the state of the board.  
     [0362]FIG. 20 is a video screen that may be displayed by computer system  20   a  which allows a user to review and change settings for a GSM modem including for example enabling calls under certain conditions.  
     [0363]FIG. 23 illustrates noise level measurements of generator  10  at various load conditions. Since generator  10  is designed for continuous use and to power cellular base stations, an additional super quiet muffler may be mounted on the generator in order to further reduce its noise level. Due to its relatively low noise, generator  10  may be located near to residential areas without disturbing people.  
     [0364] Referring to FIGS. 2 and 25, an auxiliary battery  109  may be included as part of generator  10  in order to guarantee the communication between modem  107  and processing system  20 . As illustrated in FIG. 25, auxiliary battery feeds the modem  107  (e.g., GSM modem  107   a ) and controller  105  in case the battery of generator  10  is damaged or has a voltage drop (e.g., during a start in low temperature conditions).  
     [0365] While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. For example, while power generator  10  was described above as providing on-site electrical power to a cellular base station, the power generator may be used to provide on site power for other applications such as providing power for a computer terminal room, residential house or apartment, office, hospital, school, restaurant, etc. The power generator connected to these other applications may be remotely monitored and controlled as discussed above.