HP Generating Set User's Manual
Contents
1. GENERATING SET INSTALLATION MANUAL FOREWORD This installation manual will guide you to the factors to be considered in the installation of your diesel generator system It discusses location and mounting of the generating set size of room ventilation and air flow engine cooling water supply or radiator location exhaust outlet fuel tank and fuel transfer system By following the suggestions in this installation manual you will be able to plan an economical efficient generating set installation with operating characteristics suitable to each particular application You can make you work easier by enlisting the aid of an FG Wilson Distributor when planning your generating set installation Getting his advice early may save cost and avoid problems He knows engines electrical equipment local laws and insurance regulations With his help you can be sure your generating set installation will fulfil your needs without unnecessary cost ii 2 o N OO n FY gt e c 13 TABLE OF CONTENTS INSTALLATION FACTORS MOVING THE GENERATING SET GENERATING SET LOCATION GENERATING SET MOUNTING VENTILATION ENGINE EXHAUST EXHAUST SILENCING SOUND ATTENUATION ENGINE COOLING FUEL SUPPLY SELECTING FUELS FOR STANDBY DEPENDABILITY TABLES AND FORMULAS FOR ENGINEERING STANDBY GENERATING SETS Table 1 Length Equivalents Table 2 Area Equivalents Table 3 Mass Equivalents Table 4 Volume and Capacity Equivalents2. Table 5 Conversions for Units of Speed Table 6 Conversions of Units of Power Table 7 Conversions for Measurements of Water Table 8 Barometric Pressures and Boiling Points of Water at Various Altitudes Table 9 Conversions of Units of Flow Table 10 Conversions of Units of Pressure and Head Table 11 Approximate Weights of Various Liquids Table 12 Electrical Formulae Table 13 kVA kW Amperage at Various Voltages Conversions of Centigrade and Fahrenheit Fuel Consumption Formulas Electrical Motor Horsepower Piston Travel Break Mean Effective Pressure GLOSSARY OF TERMS Copyright 1997 by FG Wilson Engineering Ltd All rights reserved No part of the contents of this manual may be reproduced photocopied or transmitted in any form without the express prior written permission of FG Wilson Engineering Ltd PAGE N 10 13 18 19 19 19 19 20 20 20 21 21 22 22 22 23 24 25 25 25 25 25 26 1 INSTALLATION FACTORS Once the size of the generating set and the required associated control panel and switchgear have been established plans for installation can be prepared Proper attention to mechanical and electrical engineering details will assure a satisfactory power system installation Factors to be considered in the installation of a generator are Access and maintenance location Floor loading Vibration transmitted to building and equipment Ventilation of room Engine exhaust piping
3. The generating set should be located so that the engine intake draws air from the cooler part of the room If there are two or more generating sets avoid locating them so that air heated by the radiator of one set flows toward the engine intake or radiator fan of an adjacent set See figure 5 2 RADIATOR AIR DIAG ARGS INSTRUMENTATION IRANSFER SWIITH AND AUTOMATIC CON ROI FANE PANEL 2COR SW NG AIR IN ET VENTILATOR FIG 5 1 TYPICAL ARRANGEMENT FOR ADEQUATE AIR CIRCULATION AND VENTILATION 5 2 Ventilators To bring in fresh air there should be an inlet ventilator opening to the outside or at least an opening to another part of the building through which the required amount of air can enter In smaller rooms ducting may be used to bring air to the room or directly to the engine s air intake In addition an exit ventilator opening should be located on the opposite outside wall to exhaust warm air See Figure 5 3 Both the inlet and exit ventilators should have louvres for weather protection These may be fixed but preferably should be movable in cold climates For automatic starting generating sets if the louvres are movable they should be automatically operated and should be programmed to open immediately upon starting the engine RAG ATOR AIR AIRFLOW zQUAL O ENG NES ZZD 227 227 22227 27 21 LLLI OPTIONAL NLE NR NIFT VLNIILAITCIA OPTICINAI INLET
4. U S S IMP Ft ad Hr 62 42 ae aa 0 01602 1 on 0 4536 fee ee cd One unit in the left hand column equals the value of units under the top heading Table 8 Barometric Pressures and Boiling Points of Water at Various Altitudes Barometric Pressure Water Boiling a Ft Inches of Ib in Feet Water Mercur Lm 5 _ ___ oo v ho ho o e o 9o 9e auld Poel hod hrd hal e e 00 6000 ae mm psc 85 2 One unit in the left hand column equals the value of units under the top heading 21 Table 9 Conversions of Units of Flow Gallons Minute Gallons Da 0 001440 0 00223 0 2271 0 0630 Gallon Minute Gallons Da DTE i019 2832 4 403 0 00634 0 00981 0 2778 One unit in the left hand column equals the value of units under the top heading Table 10 Conversions of Units of Pressure and Head 0 0394 0 5352 0 01934 0 00136 0 0013 EA Hg 13 5951 11330 0 49115 0 03453 0 0334 3 386 lin 1 86827 0 0736 0 0833 0 03613 0 00254 0 0025 0249 1 ft 224192 0 8827 0 43352 0 030479 0 0295 2 989 1 Ib in 1 735 559 28 959 3937117 32 8093 142233 0 9678 98 07 m Atmos kPa One unit in the left hand column equals the value of units under the top heading Table 11 Approximate Weights of Various Liquids Gallon Diesel Fuel Ethylene Glycol Furnace Oil Kerosene 6 25 7 1 0 75 85 Lu
5. including fuel characteristics and engine operating conditions The fuels commonly known as high grade fuels seldom contribute to the formation of harmful engine deposits and corrosion On the other hand while refining improves the fuel it also lowers the B T U or heat value of the fuel As a result the higher grade fuels develop slightly less power than the same quantity of low grade fuel This is usually more than offset by the advantages of high grade fuels such as quicker starts and less frequent overhauls Before using low grade fuels therefore some understanding of the problems and extra costs that may be encountered is necessary Fuels with high sulphur content cause corrosion wear and deposits in the engine Fuels that are not volatile enough or don t ignite rapidly may leave harmful deposits in the engine and may cause poor starting or running under adverse operating conditions The use of low grade fuels may require the use of high priced higher detergent lubricating oils and more frequent oil changes 11 2 Fuel Selection Guide Specify fuel properties according to the following chart Final Boiling Point Cetane Sulphur Number Number Min Max 40 05 290 C 550 F mmer 315 C 600 F Selecting a fuel that keeps within these specifications will tend to reduce the possibility of harmful deposits and corrosion in the engine both of which could result in more frequent overhauls and gre
6. sealed fuel level gauges and no manual fill facility All other connections on top of the tank must be sealed to prevent leakage Fuel System 2 is not compatible with the polyethylene fuel tanks standard on smaller generator sets The optional metal tank is required A 2001 Series control system or above is required Distance A in Figure 10 2 is limited to 1400mm for all generator sets with metal basetanks Fuel System 4 Some installations may require a system where fuel is pumped from a free standing bulk tank see Figure 10 4 This pumped system would only be used if gravity feed is not possible from the bulk tank to the basetank Figure 10 4 Typical Layout with Fuel System 4 The key components are the above ground bulk fuel tank item 1 remote fuel system controls item 2 located in the generator set control panel an AC Fuel Pump item 3 a DC motorised fuel valve item 4 fuel level switches in the basetank item 5 the fuel supply line item 6 an extended vent return line continuous rise on the basetank item 7 a fuel strainer item 8 and an isolating valve at the bulk tank item 9 When set to automatic the system operates as follows low fuel level in the basetank is sensed by the fuel level sensor The DC motorised valve is opened and the pump begins to pump fuel from the bulk tank to the basetank through the supply line To help ensure that clean fuel reaches the engine fuel from the bulk tank is
7. and insulation Noise reduction Method of engine cooling Size and location of fuel tank Local national or insurance regulations Smoke and emissions requirements 2 MOVING THE GENERATING SET The generating set baseframe is specifically designed for ease of moving the set Improper handling can seriously damage the generator and components Using a forklift the generating set can be lifted or pushed pulled by the baseframe An optional Oil Field Skid provides fork lift pockets if the set will be regularly moved Never lift the generating set by attaching to the engine or alternator lifting lugs For lifting the generating set lift points are provided on the baseframe Shackles and chains of suitable length and lifting capacity must be used and a spreader bar is required to prevent damaging the set See figure 2 1 An optional single point lifting bale is available if the generating set will be regularly moved by lifting 3 GENERATING SET LOCATION The set may be located in the basement or on another floor of the building on a balcony in a penthouse on the roof or even in a separate building Usually it is located in the basement for economics and for convenience of operating personnel The generator room should be large enough to provide adequate air circulation and plenty of working space around the engine and alternator If it is necessary to locate the generating set outside the building it can be furni
8. duct material rubber or suitable fabric between the radiator and the fixed discharge duct is required to isolate vibration and provide freedom of motion between the generating set and the fixed duct HORIZONTALLY RAG ATOR AIR FLOW FIG 9 2 REMOTE RADIATOR CONNECTED DIRECTLY TO ENGINE COOLING SYSTEM 9 2 Remote Radiator A remote radiator with electric motor driven can be installed in any convenient location away from the generating set See figure 9 2 A well designed remote radiator has many useful features and advantages that provide greater flexibility of generating set installations in buildings More efficient venturi shroud and fan provide a substantial reduction in horsepower required for engine cooling The fan may be driven by a thermostatically controlled motor which will only draw power from the generating set when required to cool the engine A remote radiator can be located outdoors where there is less air flow restriction and air is usually cooler than engine room air resulting in higher efficiency and smaller size radiator and fan noise is removed from the building Remote radiators must be connected to the engine cooling system by coolant piping including flexible sections between engine and piping 9 3 Remote Radiator Heat Exchanger System Another type of remote radiator system employs a heat exchanger at the engine See figure 9 3 and 9 4 In this application the heat exchanger functi
9. strained just prior to the motorised valve When the basetank is full as sensed by the fuel level sensor the pump stops and the motorised valve is closed Any overflow into the basetank or overpressure in the basetank will flow back to the bulk tank via the extended vent With this system the basetank must include an overflow via the return line sealed fuel level gauges and no manual fill facility All other connections on 15 top of the tank must be sealed to prevent leakage Fuel System 4 is not compatible with the polyethylene fuel tanks standard on smalle generator sets The optional metal tank is required A 2001 Series control system or above is required Distance A on Figure 10 4 is limited to 1400mm for all generator sets with metal basetanks Note that the maximum restriction caused by friction losses and height of the return line should not exceed 2 psi 10 3 Tank Construction Fuel tanks are usually made of welded sheet steel or reinforced plastic If an old fuel tank is used be sure it is made of a proper material It should be cleaned thoroughly to remove all rust scale and foreign deposits Connections for fuel suction and return lines must be separated as much as possible to prevent re circulation of hot fuel and to allow separation of any gases entrained in the fuel Fuel suction lines should extend below the minimum fuel level in the tank Where practical a low point in the tank should be equipped w
10. the emergency power less dependable Not only is such an engine less dependable than a diesel but often the same storm or accident that disrupts the normal electric power also cuts off gas service Thus a natural gas engine would be disabled at the very time it is needed By contrast a diesel engine with its fuel in a nearby tank is a self contained system that does not depend on outside services It is more dependable and affords greater standby protection than systems which depend on a public utility for fuel 18 12 TABLES AND FORMULAS FOR ENGINEERING STANDBY GENERATING SETS Table 1 Length Equivalents wies i ixoxo oa xm iex 1 ____ 1 139370 39 1093 6 0621 imc 25400 100254 1 _____ 00833 0028 ppme J ose Je Jr Joss jJ ayara fj j ww Jh h J 1 Mite f 169 160 63360 5280 1760 J One unit in the left hand column equals the value of units under the top heading Table 2 Area Equivalents im 1 00044 006456 __ TEE 1Ace _ __ 43 560 1 00015625 4047 ____ 04047 0004047 27878400 640 Hisp gom qe Je J0 Ja c c ques cn 107639 __ 2471 0 003861 10763867 2471 0 3861 One unit in the left hand column equals the value of units under the top heading Table 3 Mass Equivalents ai lonse ee eee cae eun 10
11. 18 f Jf 10550 6700 6360 5780 5285 4220 1055 760 12040 7680 7280 6035 4810 872 5760 5460 4980 4880 4525 3610 998 654 9 970 950 g uv e N oo I E le 2 CN Oya SA Barl KOA B BIAS 5 SINE NI Oy Ty tT oo OLA lal ala en lt DI 2 e o ge isis e o gt n 3 e9 s j8 E S 5 2 525 28 5 9 2 SEE IE m 8 a S ala ALA A om A ale e st en ci INI NTN oue gt ajojn gt gt gt gt SB SIR 2 2 412 cssc S n 8 2 m a 8 e N T e Pe e Pa 5 N N N en t 0 ejn nl elan enlasa eenen un e wn oo in as 22 as s ls 2 lg g mjm een e en en vt N ON B o e N N C o N 24 Conversions of Centigrade and Fahrenheit Water freezes at 0 C 32 F Water boils at 100 C 212 F F 1 8 x C 32 C 0 5555 F 32 Fuel Consumption Formulas Fuel Consumption 16 hr Specific Fuel Cons lb BHP hr x BHP Spec Fuel Cons lb BHP hr x BHP Fuel Specific Weight Ib US gal F
12. D EXPANSION JOINT RAIN CAP EXHAUST SILENCER FIG 6 1 TYPICAL EXHAUST SYSTEM INSTALLATION 6 2 Exhaust Pipe Flexible Section A flexible connection between the manifold and the exhaust piping system should be used to prevent transmitting engine vibration to the piping and the building and to isolate the engine and piping from forces due to thermal expansion motion or weight of piping A well designed flex section will permit operation with 13 mm 0 5 in permanent displacement in any direction of either end of the section without damage Not only must the section have the flexibility to compensate for a nominal amount of permanent mismatch between piping and manifold but it must also yield readily to intermittent motion of the Generating Set on its vibration isolators in response to load changes The flexible connector should be specified with the Generating Set 6 3 Exhaust Pipe Insulation No exposed parts of the exhaust system should be near wood or other inflammable material Exhaust piping inside the building and the silencer if mounted inside should be covered with suitable insulation materials to protect personnel and to reduce room temperature A sufficient layer of suitable insulating material surrounding the piping OPTIGNAL Sl FT Vr AND PXPANSION JOINT OPTIONAI SOUND REDUCING MATERIAL AIR GLIDIT VANS AGCISS IOOR FIG 62 HORIZONTALLY MOUNTED EXHAUST SILENCER WITH EXHAUST PIPE AND RAD
13. FIG 5 2 TYPICAL ARRANGEMENT FOR PROPER VENTILATION WITH MULTIPLE GENERATING SETS 5 3 Inlet Ventilator Size Before calculating the inlet ventilator size it is necessary to take into account the radiator cooling air flow requirements and the fan static pressure available when the generating set is operating at its rated load In standard room installations the radiated heat is already taken into account in the radiator air flow For generator room installation with remote radiators the room cooling airflow is calculated using the total heat radiation to the ambient air of the engine and alternator and any part of the exhaust system Engine and alternator cooling air requirements for FG Wilson generating sets when operating at rated power are shown on specification sheets Exhaust system radiation depends on the length of pipe within the room the type of insulation used and whether the silencer is located within the room or outside It it usual to insulate the exhaust piping AIR INLET VENTILATOR and silencer so that heat radiation from this source may be neglected in calculating air flow required for room cooling After determining the required air flow into the room calculate the size of inlet ventilator opening to be installed in the outside wall The inlet ventilator must be large enough so that the negative flow restriction will not exceed a maximum of 10 mm 04 in H O Restrict
14. IATOR AIR UTILISING COMMON STACK SOUNL REDLS N MATERIAL and silencer and retained by a stainless steel or aluminium sheath may substantially reduce heat radiation to the room from the exhaust system An additional benefit of the insulation is that it provides sound attenuation to reduce noise in the room 6 4 Minimising Exhaust Flow Restriction Free flow of exhaust gases through the pipe is essential to minimise exhaust back pressure Excessive exhaust back pressure seriously affects engine horsepower output durability and fuel consumption Restricting the discharge of gases from the cylinder causes poor combustion and higher operating temperatures The major design factors that may cause high back pressure are Exhaust pipe diameter too small Exhaust pipe too long Too many sharp bends in exhaust system Exhaust silencer restriction too high At certain critical lengths standing pressure waves may cause high back pressure AIR GUIDE VANES NEARY ACCESS DOOR FIG 6 3 RADIATOR AIR DISCHARGING INTO SOUND INSULATED STACK CONTAINING EXHAUST SILENCER Excessive restriction in the exhaust system can be avoided by proper design and construction To make sure you will avoid problems related to excessive restriction ask The FG Wilson distributor to review your design The effect of pipe diameter length and the restriction of any bends in the system can be calculated to make sure your exhaust system is ade
15. alf the job since it can only be used in the engine water side of the heat exchanger There must be assurance that the raw water source will not freeze 9 6 Water Conditioning Soft water should always be used in the engine whether cooling is by radiator or by heat exchanger Adding a commercial softener is the easiest and most economical method of water softening Your FG Wilson Distributor can recommend suitable softeners Manufacturers instructions should be carefully followed 13 FLOW gt VALV RAW WAT7R LISS AGE FY GLAS FIG 9 5 HEAT EXCHANGER COOLING SYSTEM 10 FUEL SUPPLY A dependable fuel supply system must assure instant availability of fuel to facilitate starting and to keep the engine operating This requires at a minimum a small day tank usually incorporated into the generating set baseframe called a basetank located close to the set With generally only a capacity of 8 hours operation this day tank is often backed up by an auxiliary remote fuel system including a bulk storage tank and the associated pumps and plumbing Extended capacity basetanks are also generally available for longer operation prior to refuelling Especially for standby generating sets it not advisable to depend on regular delivery of fuel The emergency that requires use of the standby set may also interrupt the delivery of fuel 10 1 Fuel Tank Location The day tank should be located as close to t
16. ater maintenance expense Specify exact fuel properties to your local fuel supplier 11 3 Maintaining Fresh Fuel Most fuels deteriorate if they stand unused for a period of many months With standby generators it is preferable to store only enough fuel to support a few days or even only eight hours of continuous running of the Generating Set so that normal engine testing will turn over a tank full within a year and a half Other solutions are to add inhibitors to the fuel or to obtain greater turnover by using the fuel for other purposes A gum inhibitor added to diesel fuel will keep it in good condition up to two years If the building furnace has an oil burner it is possible to burn diesel fuel in the furnace connecting both the engine and the furnace to the same tank In this way a large supply of diesel fuel is available for emergency use by the Generating Set and the fuel supply is continuously turned over since it is being burned in the furnace Thus there is no long term storage problem 11 4 Self Contained Dependability In some areas where natural gas is cheap natural gas spark ignition engines are used in Generating Sets that are intended for continuous service For standby service however this is not recommended The natural gas supply and regulation system adds substantially to the complexity of the installation and there is little to be gained in terms of fuel cost over a period of time More important it makes
17. be Oil Medium 7 5 7 7 0 90 0 92 Water Gasoline 5 6 6 3 0 67 0 75 22 Table 12 Electrical formulae Single Phase Three Phase Kilowatts kW Ix Vx PF J3xIx Vx PF IxV 1000 1000 1000 Kilovolt Amperes kVA IxV 43x VxE 1000 1000 Electric Motor IxVxEff xPF V3xIxVxEff xPF IxVxEff Horsepower 746 nr 746 Output HP Amperes I HPx 746 HPx 746 HPx 746 When Horsepower vx pg x PF J3xVxBff x PF Eff is known Amperes I kW x 1000 kW x 1000 kW x 1000 When Kilowatts VxPF J3 xVxPF known Amperes I kVAx 1000 kVAx 1000 When kVA is Js xV known Where V Volts I Amperes Eff Percentage Efficiency Watts PF Power Factor Ix V 23 TABLE 13 KVA EW AMPERAGE AT VARIOUS VOLTAGES 0 8 Power Factor 121 139 156 522 610 695 3840 3320 3240 3015 2405 436 6780 4320 3735 2710 678 176 197 218 273 327 491 546 91 83 sil 76 61 __ 9 6 21602 384 364 332 324 31 24 61 35 903 576 546 498 487 452 36 91 66 52 120 77 73 665 65 60 d48 121 88 7 521 95 9r7 253 80 a 4 9T isi 15 1091 996 975 91 72 181 1311 105 26 143 136 123 120 13 90 226 164 1203 770 730 665 650 601 481 120 _ 88 69 1504 960 90 830 810 752 602 150 109 _ 87 1803 1150 1090 996 975 902 721 180 if 104 903 576 546 498 487 asif 3611 90 66 52 E 45 288 273 249 244 25
18. ctioning at rated conditions If the set is equipped with additional power producing devices then the stated or guaranteed net electric power must take into consideration that the auxiliaries are delivering their respective stated or guaranteed net output simultaneously unless otherwise agreed to RATED SPEED Revolutions per minute at which the set is designed to operate RATED VOLTAGE The rated voltage of an engine generating set is the voltage at which it is designed to operate REACTANCE The out of phase component of impedance that occurs in circuits containing inductance and or capacitance REAL POWER A term used to describe the product of current voltage and power factor expressed in kW RECTIFIER A device that converts AC to DC ROOT MEAN SQUARE RMS The conventional measurement of alternating current and voltage and represents a proportional value of the true sine wave SINGLE PHASE An AC load or source of power normally having only two input terminals if a load or two output terminals if a source STANDBY POWER An independent reserve source of electrical energy which upon failure or outage of the normal source provides electric power of acceptable quality and quantity so that the user s facilities may continue in satisfactory operation STAR CONNECTION A method of interconnecting the phases of a three phase system to form a configuration resembling a star or the letter Y A fourth or neutral wire can be con
19. e pipe to compensate for lengthways thermal expansion or contraction See figure 6 1 It is not normally recommended that the engine exhaust share a flue with a furnace or other equipment since there is danger that back pressure caused by one will adversely affect operation of the others Such multiple use of a flue should be attempted only if it is not detrimental to performance of the engine or any other equipment sharing the common flue The exhaust can be directed into a special stack that also serves as the outlet for radiator discharge air and may be sound insulated The radiator discharge air enters below the exhaust gas inlet so that the rising radiator air mixes with the exhaust gas See figures 6 2 and 6 3 The silencer may be located within the stack or in the room with its tail pipe extending through the stack and then outward Air guide vanes should be installed in the stack to turn radiator discharge air flow upward and to reduce radiator fan air flow restriction or the sound insulation lining may have a curved contour to direct air flow upward For a generating set enclosed in a penthouse on the roof or in a separate outdoor enclosure or trailer the exhaust and radiator discharges can flow together above the enclosure without a stack Sometimes for this purpose the radiator is mounted horizontally and the fan is driven by an electric motor to discharge air vertically SILENCER PIPEWORK WALL SLEEVE SUPPORTS AN
20. ement of electric flow One ampere of current will flow when one volt is applied across a resistance of one ohm APPARENT POWER VA A term used when the current and voltage are not in phase i e voltage and current do not reach corresponding values at the same instant The resultant product of current and voltage is the apparent power and is expressed in kVA AUTOMATIC SYNCHRONIZER This device in its simplest form is a magnetic type control relay which will automatically close the generator switch when the conditions for paralleling are satisfied BREAK MEAN EFFECTIVE PRESSURE BMEP This is the theoretical average pressure on the piston of an engine during the power stroke when the engine is producing a given number of horsepower It is usually expressed in pounds inch The value is strictly a calculation as it cannot be measured since the actual cylinder pressure is constantly changing The mean or average pressure is used to compare engines on assumption that the lower the BMEP the greater the expected engine life and reliability In practice it is not a reliable indicator of engine performance for the following reasons The formula favours older design engines with relatively low power output per cubic inch of displacement in comparison with more modern designs Modern engines do operate with higher average cylinder pressures but bearings and other engine parts are designed to withstand these higher pressures and to still provide
21. engine does not have to drive a radiator fan there is more reserve power available The raw water side of the heat exchanger requires a dependable and economical supply of cool water Soft water is desired to keep the heat exchanger in good operating condition For standby service a well lake or cooling tower is preferred over city water since the latter may fail at the same time that normal electric power fails making the generator useless 12 RAL Ie 4 VI EX MACE gt AUXILIARY FIG 9 4 TYPICAL HEAT EXCHANGER INSTALLATION 9 5 Antifreeze Protection If the engine is to be exposed to low temperatures the cooling water in the engine must be protected from freezing In radiator cooled installations antifreeze may be added to the water to prevent freezing Ethylene glycol permanent antifreeze is recommended for diesel engines It includes its own corrosion inhibitor which eventually may have to be replenished Only a non chromate inhibitor should be used with ethylene glycol The proportion of ethylene glycol required is dictated primarily by the need for protection against freezing in the lowest ambient air temperature that will be encountered The concentration of ethylene glycol must be at least 30 to afford adequate corrosion protection The concentration must not exceed 67 to maintain adequate heat transfer capability For heat exchanger cooling antifreeze does only h
22. equal or greater life and reliability than the older designs The formula also implies greater reliability when the same engine produces the same power at a higher speed Other things being equal it is unlikely that a 60 Hz generating set operating at 1800 RPM is more reliable than a comparable 50 Hz generating set operating at 1500 RPM Also it is doubtful that a generator operating at 3000 RPM will be more reliable than one operating at 1500 RPM even if the latter engine has a significantly higher BMEP The BMEP for any given generating set will vary with the rating which changes depending on fuel altitude and temperature The BMEP is also affected by generator efficiency which varies with voltage and load CAPACITANCE C If a voltage is applied to two conductors separated by an insulator the insulator will take an electrical charge Expressed in micro farads uf CIRCUIT BREAKER A protective switching device capable of interrupting current flow at a pre determined value CONTINUOUS LOAD Any load up to and including full rated load that the generating set is capable of delivering for an indefinitely long period except for shut down for normal preventive maintenance CONTINUOUS RATING The load rating of an electric generating system which is capable of supplying without exceeding its specified maximum temperature rise limits 26 CURRENT I The rate of flow of electricity DC flows from negative to positive AC alternates in direct
23. fining practices employed and the nature of the crude oils from which they are produced For example fuel oils may be produced within the boiling range of 148 to 371 C 300 to 700 F having many possible combinations of other properties The additional contaminants present in low grade fuels may result in darker exhaust and more pronounced odour This may be objectionable in hospitals offices commercial and urban locations Thus location application and environmental conditions should be considered when selecting fuel The Generating Set owner may elect to use a low grade fuel because high grade fuels are not readily available in his area or because he can realise a net saving with low grade fuels despite higher engine maintenance costs In that case frequent examination of lubrication oil should be made to determine sludge formation and the extent of lube oil contamination Aside from the various grades of fuel oil commonly used in diesel engines aircraft jet fuels also are sometimes used especially in circumstances where the jet fuels are more readily available than conventional fuels Jet fuels are lower in B T U content and lubrication quality than conventional fuels As a result some diesel fuel systems must undergo major modifications to accommodate this type of fuel For use of jet fuel please consult FG Wilson 17 Reliable operation of diesel engines may vary from one fuel to another depending on many factors
24. ge Fuel System is not compatible with the polyethylene fuel tanks standard on smaller generator sets The optional metal tank is required A 2001 Series control system or above is required The position of the bulk fuel tank should take into account that the maximum suction lift of the fuel transfer pump is approximately 3 metres and that the maximum restriction caused by the friction losses in the return fuel line should not exceed 2 psi Fuel System 2 The bulk tank is located higher than the basetank With this system the fuel is gravity fed from the bulk tank to the basetank See figure 10 2 Figure 10 1 Typical Layout with Fuel System1 The key components are the bulk fuel tank item 1 which is lower than the basetank remote fuel system controls item 2 located in the generator set control panel an AC powered electric fuel pump item 3 fuel level switches in the basetank item 4 an extended vent on the basetank item 5 the fuel supply line item 6 the fuel return line item 7 and a fuel strainer item 8 on the inlet side of the pump When set to automatic the system operates as follows low fuel level in the basetank is sensed by the fuel level sensor The pump begins to pump fuel from the bulk tank to the basetank through the fuel supply line To help ensure that clean fuel reaches the engine fuel from the bulk tank is strained just prior to the electric fuel pump When the basetank is full as sensed by
25. he generating set as possible Normally it is safe to store diesel fuel in the same room with the generating set because there is less danger of fire or fumes with diesel than with petrol gasoline Thus if building codes and fire regulations permit the day tank should be located in the base of the generating set along side the set or in an adjacent room Where an remote fuel system is to be installed with a bulk storage tank the bulk tank may be located outside the building where it will be convenient for refilling cleaning and inspection It should not however be exposed to freezing weather because fuel flow will be restricted as viscosity increases with cold temperature The tank may be located either above or below ground level 10 2 Remote Fuel Systems Three types of remote fuel systems are recommended by the manufacturer Fuel System 1 Installations where the bulk fuel tank is lower than the day tank Fuel System 2 Installations where the bulk fuel tank is higher than the day tank Fuel System 4 Installations where fuel must be pumped from a free standing bulk fuel tank to the day tank Fuel System 1 The bulk fuel tank is lower than the day tank With this system the fuel must be pumped up from the bulk tank to the day tank which is integrated into the baseframe See figure 10 1 fuel level gauges on the basetank and no manual fill facility All other connections on top of the tank must be sealed to prevent leaka
26. he engine without requiring a great amount of headroom Silencers or exhaust piping within reach of personnel should be protected by guards or insulation Indoors it is preferable to insulate the silencer and piping because the insulation not only protects personnel but it reduces heat radiation to the room and further reduces exhaust system noise Silencers mounted horizontally should be set at a slight angle away from the engine outlet with a drain fitting at the lowest point to allow the disposal of any accumulated moisture 8 SOUND ATTENUATION If noise level must be limited it should be specified in terms of a sound pressure level at a given distance from the generator enclosure Then the enclosure must be designed to attenuate the noise generated inside the enclosure to produce the required level outside Don t attempt to make this noise level unnecessarily low because the means of achieving it may be costly Use of resilient mounts for the generating set plus normal techniques for controlling exhaust intake and radiator fan noise should reduce generating set noise to an acceptable level for many installations If the remaining noise level is still too high acoustic treatment of either the room or the generating set is necessary Sound barriers can be erected around the generating set or the walls of the generator room can be sound insulated or the generating set can be enclosed in a specially developed sound insulated encl
27. high end away from the drain plug 10 5 Day Tank Capacity The capacity of the day tank is based on the fuel consumption and the expected number of hours of operation that is requested between refills Particularly with standby generators the availability of fuel delivery service will determine the number of operating hours that must be provided for Don t depend on quick service the very day your set starts to operate A power outage may hamper your supplier s operation also In addition the size of the day tank should be large enough to keep fuel temperatures down since some engines return hot fuel used to cool the injectors Extra Capacity With Fuel Without Fuel Coolers Coolers P910 P1100E 1500 litres 3000 litres P1250 P1650E 2250 litres 4500 litres P1700 P2200E 3000 litres 6000 litres 16 11 SELECTING FUELS FOR STANDBY DEPENDABILITY The types of fuels available for diesel engines vary from highly volatile jet fuels and kerosene to the heavier fuel oils Most diesel engines are capable of burning a wide range of fuels within these extremes The following information will assist you in selecting the type of fuel that will afford the best overall performance and reliability of your Generating Set 11 1 Types Of Fuel Oil The quality of fuel oil can be a dominant factor in satisfactory engine life and performance A large variety of fuel oils are marketed for diesel engine use Their properties depend upon the re
28. iency performance The fan drive pulley idler pulley and engine crankshaft pulley are precisely aligned and connected in a three point drive by the belts This second type of set mounted radiator usually uses an airfoil bladed fan with the close fitting shroud The proper radiator and fan combinations will be provided by FG Wilson and furnished with the generating set Air requirements for cooling a particular FG Wilson generator are given in the specification sheet The radiator cooling air must be relatively clean to avoid clogging the radiator core Adequate filtration of air flowing into the room should assure relatively clean air However if the air at the site normally contains a high concentration of dirt lint sawdust or other matter the use of a remote radiator located in a cleaner environment may alleviate a core clogging problem It is recommended that a set mounted radiator s discharge air should flow directly outdoors through a duct that connects the radiator to an opening in an outside wall The engine should be located as close to the outside wall as possible to keep the ducting short If the ducting is too long it may be more economical to use a remote radiator The air flow restriction of the discharge and the inlets duct should not exceed the allowable fan static pressure When the set mounted radiator is to be connected to a discharge duct a duct adapter should be specified for the radiator A length of flexible
29. ion The current flow theory is used conventionally in power and the current direction is positive to negative CYCLE One complete reversal of an alternating current or voltage from zero to a positive maximum to zero to a negative maximum back to zero The number of cycles per second is the frequency expressed in Hertz Hz DECIBEL dB Unit used to define noise level DELTA CONNECTION A three phase connection in which the start of each phase is connected to the end of the next phase forming the Greek letter Delta D The load lines are connected to the corners of the delta In some cases a centre tap is provided on each phase but more often only on one leg thus supplying a four wire output DIRECT CURRENT An electric current which flows in one direction only for a given voltage and electrical resistance A direct current is usually constant in magnitude for a given load EFFICIENCY The efficiency of a generating set shall be defined as the ratio of its useful power output to its total power input expressed as a percentage FREQUENCY The number of complete cycles of an alternating voltage or current per unit of time usually per second The unit for measurement is the Hertz Hz equivalent to 1 cycle per second CPS FREQUENCY BAND The permissible variation from a mean value under steady state conditions FREQUENCY DRIFT Frequency drift is a gradual deviation of the mean governed frequency above or below the desired freq
30. ion values of air filters screens and louvres should be obtained from manufacturers of these items 5 4 Exit Ventilator Size Where the engine and room are cooled by a set mounted radiator the exit ventilator must be large enough to exhaust all of the air flowing through the room except the relatively small amount that enters the engine intake AIR EXIT VENTILATOR FIG 5 3 INLET AND EXIT VENTILATORS 6 ENGINE EXHAUST Engine exhaust must be directed to the outside through a properly designed exhaust system that does not create excessive back pressure on the engine A suitable exhaust silencer should be connected into the exhaust piping Exhaust system components located within the engine room should be insulated to reduce heat radiation The outer end of the pipe should be equipped with a rain cap or cut at 60 to the horizontal to prevent rain or snow from entering the exhaust system If the building is equipped with a smoke detection system the exhaust outlet should be positioned so it cannot set off the smoke detection alarm 6 1 Exhaust Piping For both installation economy and operating efficiency engine location should make the exhaust piping as short as possible with minimum bends and restrictions Usually the exhaust pipe extends through an outside wall of the building and continues up the outside of the wall to the roof There should be a sleeve in the wall opening to absorb vibration and an expansion joint in th
31. ith a drain valve or plug in an accessible location to allow periodic removal of water condensation and sediment Or a hose may be inserted through the tank s filter neck when necessary to suck out water and sediment The filler neck of the bulk fuel tank should be located in a clean accessible location A removable wire screen of approximately 1 6 mm 1 16 inch mesh should be placed in the filler neck to prevent foreign material from entering the tank The filler neck cap or the highest point in the tank should be vented to maintain atmospheric pressure on the fuel and to provide pressure relief in case a temperature rise causes the fuel to expand It will also prevent a vacuum as fuel is consumed The tank may be equipped with a fuel level gauge either a sight gauge or a remote electrical gauge 10 4 Fuel Lines The fuel lines can be of any fuel compatible material such as steel pipe or flexible hoses that will tolerate environmental conditions Fuel delivery and return lines should be at least as large as the fitting sizes on the engine and overflow piping should be one size larger For longer runs of piping or low ambient temperatures the size of these lines should be increased to ensure adequate flow Flexible piping should be used to connect to the engine to avoid damage or leaks caused by engine vibration The fuel delivery line should pick up fuel from a point no lower than 50 mm 2 from the bottom of tank at the
32. mc 1 00605 02855 J ICM merse um _ 5 1K egram 3527 225 _ _ _ db One unit in the left hand column equals the value of units under the top heading 19 Table 4 Volume and Capacity Equivalents Gallons Gallons 0 1337 0 00495 0 003785 0 833 3 785 U S Liq Gal One unit in the left hand column equals the value of units under the top heading Table 5 Conversions for Units of Speed Feet Secon Feet Min Miles Hr Meters Sec Meters Mi d n 1 1Foo Sec 60 0 0688 03048 __ 18288 1Fow Mim 00167 1 01136 0008 1M eHr _ 1467 88 Ji 2682 1693 1 3281 19688 1 _ __ 1MeterMin 005468 00328 hi __ o oea 0278 ___ 1 ____ One unit in the left hand column equals the value of units under the top heading Table 6 Conversions For Units Of Power Unit Horsepower Foot Ib Minute Kilowatts Metric Btu Minute Horsepower ee ONES b Minute 260 Lu 1360 5658 Horsepower 0 0236 771 6 0 0176 0 0239 One unit in the left hand column equals the value of units under the top heading Mechanical power and ratings of motors and engines are expressed in horsepower Electrical power is expressed in watts or kilowatts 20 Table 7 Conversions for Measurements of Water Feet Gal Gal Litres Head Ib in Ton Ft Head Ft Min Gal
33. nected to the centre point 28 TELEPHONE INFLUENCE FACTOR TIF The telephone influence factor of a synchronous generator is a measure of the possible effect of harmonics in the generator voltage wave on telephone circuits TIF is measured at the generator terminals on open circuit at rated voltage and frequency THREE PHASE Three complete voltage current sine waves each of 360 electrical degrees in length occurring 120 degrees apart A three phase system may be either 3 wire or 4 wire 3 wires and a neutral UNINTERRUPTABLE POWER SUPPLY UPS A system designed to provide power without delay or transients during any period when the normal power supply is incapable of performing acceptably UNITY POWER FACTOR A load whose power factor is 1 0 has no reactance s causing the voltage wave to lag or lead the current wave WATT Unit of electrical power In DC it equals the volts times amperes In AC it equals the effective volts times the effective amps times power factor times a constant dependent on the number of phases 29 276 851 FG WILSON GROUP HEADQUARTERS Old Glenarm Road Larne Co Antrim BT40 1EJ Northern Ireland United Kingdom Telephone 44 028 2826 1000 Fax 44 028 2826 1111 INSTALL DOC 0601
34. ng flexible connections between the engine and fuel lines exhaust system radiator air discharge duct conduit for control and power cables and other externally connected support systems 4 2 Floor Loading Floor loading depends on the total generating set weight including fuel and water and the number and size of isolator pads With the baseframe mounted directly on the floor the floor loading is Total Generating Set Weight Area of Skids With vibration isolation between the baseframe and the floor if the load is equally distributed over all isolators the floor loading is Floor Loading Total Generating Set Weight Fl Loading Pad Area x Number of Pads Thus floor loading can be reduced by increasing the number of isolation pads If load is not equally distributed the maximum floor pressure occurs under the pad supporting the greatest proportion of load assuming all pads are the same size Load on Heaviest Loaded Pa Pad Area Max Floor Pressure ILLAIBL 5 RUST SONNECTION FIG 4 1 REDUCING VIBRATION TRANSMISSION 5 VENTILATION Any internal combustion engine requires a liberal supply of cool clean air for combustion If the air entering the engine intake is too warm or too thin the engine may not produce its rated power Operation of the engine and alternator radiates heat into the room and raises the temperature of the room air Therefore ventilation of the generator ro
35. of 100 to 400 cfm 00056 for engine combustion airflow of 400 to 700 cfm 00049 for engine combustion airflow of 700 to 2000 cfm 00044 for engine combustion airflow of 2000 to 5400 cfm L length of exhaust pipe in feet R exhaust density in pounds per cubic foot 41 1 R Exhaust temperature 460 F Q exhaust gas flow in cubic feet per minute D inside diameter of exhaust pipe in inches Available from engine specification sheet These formulae assume that the exhaust pipe is clean commercial steel or wrought iron The back pressure is dependent on the surface finish of the piping and an increase in the pipe roughness will increase the back pressure The constant 41 1 is based on the weight of combustion air and fuel burned at rated load and SAE conditions See engine specification sheet for exhaust gas temperature and air flow Conversion tables to other units are provided in Section 12 EXHALISI OL LEI CLEXI3 7 SECTION FIG 6 4 MEASURING EXHAUST PIPE LENGTH TO DETERMINE EXHAUST BACK PRESSURE 7 EXHAUST SILENCING Excessive noise is objectionable in most locations Since a large part of the generating set noise is produced in the engine s pulsating exhaust this noise can be reduced to an acceptable level by using an exhaust silencer The required degree of silencing depends on the location and may be regulated by law For example the noise of an engine is objectionable in a hospital area but generall
36. om is necessary to limit room temperature rise and to make clean cool intake air available to the engine When the engine is cooled by a set mounted radiator the radiator fan must move large quantities of air through the radiator core There must be enough temperature difference between the air and the water in the radiator to cool the water sufficiently before it re circulates through the engine The air temperature at the radiator inlet depends on the temperature rise of air flowing through the room from the room inlet ventilator By drawing air into the room and expelling it outdoors through a discharge duct the radiator fan helps to maintain room temperature in the desirable range In providing ventilation the objective is to maintain the room air at a comfortable temperature that is cool enough for efficient operation and full available power but it should not be so cold in winter that the room is uncomfortable or engine starting is difficult Though providing adequate ventilation seldom poses serious problems each installation should be analysed by both the distributor and the customer to make sure the ventilation provisions are satisfactory 5 1 Circulation Good ventilation requires adequate flow into and out of the room and free circulation within the room Thus the room should be of sufficient size to allow free circulation of air so that temperatures are equalised and there are no pockets of stagnant air See figure 5 1
37. ons as an intermediate heat exchanger to isolate the engine coolant system from the high static head of the remote radiator coolant The engine pump circulates engine coolant through the engine and the element of the heat exchanger WATER TC RAL AI CR VERTICALLY MOUNT EE RADIATOR AIR FLOW 3AZOF OR DECK WAT R FROM RAC ATOR ALIXILIARY WATER PUMI PXGHANGE R FIG 9 3 REMOTE RADIATOR ISOLATED FROM ENGINE COOLING SYSTEM BY HEAT EXCHANGER A separate pump circulates radiator coolant between the remote radiator and the heat exchanger tank Heat exchangers also are used for cooling the engine without a radiator as described in the following section 9 4 Heat Exchanger Cooling A heat exchanger may be used where there is a continuously available supply of clean cool raw water Areas where excessive foreign material in the air might cause constant radiator clogging such as in saw mill installations may be logical sites for heat exchanger cooling A heat exchanger cools the engine by transferring engine coolant heat through passages in the elements to cool raw water Engine coolant and raw cooling water flows are separated completely in closed systems each with its own pump and never intermix A heat exchanger totally replaces the radiator and fan See figure 9 5 It usually is furnished as part of the generating set assembly mounted on the engine although it can be located remotely Since the
38. osure See figure 8 1 In most cases it is necessary that the air intake and air discharge openings will have to be fitted with sound attenuators If it is desired to protect operating personnel from direct exposure to generating set noise the instruments and control station may be located in a separate sound insulated control room 9 ENGINE COOLING Some diesel engines are air cooled but the majority are cooled by circulating a liquid coolant through the oil cooler if one is fitted and through passages in the engine block and head Hot coolant emerging from the engine is cooled and recirculated through AIR GUTLET ATTENLATOR the engine Cooling devices are commonly coolant to air radiator or coolant to raw water heat exchanger types In the most common generating set installation the engine coolant is cooled in a set mounted radiator with air blown through the radiator core by an engine driven fan Some installations use a remotely mounted radiator cooled by an electric motor driven fan Where there is a continuously available supply of clean cool raw water a heat exchanger may be used instead of a radiator the engine coolant circulates through the heat exchanger and is cooled by the raw water supply An important advantage of a radiator cooling system is that it is self contained If a storm or accident disrupted the utility power source it might also disrupt the water supply and disable any generating set whose
39. quate without excessive back pressure The longer the pipe and the more bends it contains the larger the diameter required to avoid excessive flow restriction and back pressure The back pressure should be calculated during the installation stage to make certain it will be within the recommended limits for the engine Measure the exhaust pipe length from your installation layout See figure 6 4 Take exhaust flow data and back pressure limits from the generating set engine specification sheet Allowing for restrictions of the exhaust silencer and any elbows in the pipe calculate the minimum pipe diameter so that the total system restriction will not exceed the recommended exhaust back pressure limit Allowance should be made for deterioration and scale accumulation that may increase restriction over a period of time Elbow restriction is most conveniently handled by calculating an equivalent length of straight pipe for each elbow and adding it to the total length of pipe For elbows and flexible sections the equivalent length of straight pipe is calculated as follows 45 Elbow Length ft 0 75 x Diameter inches 90 Elbow Length ft 1 33 x Diameter inches ENGINE EXHAUST 2 Flexible Sections Length ft 0 167 x Diameter inches The following formula is used to calculate the back pressure of an exhaust system where P back pressure in inches of mercury C 00059 for engine combustion airflow
40. shed enclosed in a housing and mounted on a skid or trailer This type of assembly is also useful whether located inside or outside the building if the installation is temporary For outside installation the housing is normally weatherproof This is necessary to prevent water from entering the alternator compartment if the generating set is to be exposed to rain accompanied by high winds FIG 2 1 PROPER LIFTING ARRANGEMENT 4 GENERATING SET MOUNTING The generating set will be shipped assembled on a rigid base that precisely aligns the alternator and engine and needs merely to be set in place on vibration isolation pads for larger sets and levelled See figure 4 1 4 1 Vibration Isolation It is recommended that the generating set be mounted on vibration isolation pads to prevent the set from receiving or transmitting injurious or objectionable vibrations Rubber isolation pads are used when small amounts of vibration transmission is acceptable Steel springs in combination with rubber pads are used to combat both light and heavy vibrations On smaller generating sets these isolation pads should be located between the coupled engine alternator feet and the baseframe The baseframe is then securely attached to the floor On larger sets the coupled engine alternator should be rigidly connected to the baseframe with vibration isolation between the baseframe and floor Other effects of engine vibration can be minimised by providi
41. supply of raw water depended upon a utility Whether the radiator is mounted on the generating set or mounted remotely accessibility for servicing the cooling system is important For proper maintenance the radiator fill cap the cooling system drain cocks the fan belt tension adjustment must all be accessible to the operator 9 1 Set Mounted Radiator A set mounted radiator is mounted on the generating set base in front of the engine See figure 9 1 An engine driven fan blows air through the radiator core cooling the liquid engine coolant flowing through the radiator 1 TANK IND TANK L FIG 8 1 TYPICAL SOUND ATTENUATED INSTALLATION 10 RALIALOK DISCHARGE FLEXIBLE GUST FIG 9 1 SET MOUNTED RADIATOR DISCHARGING THROUGH OUTSIDE WALL Set mounted radiators are of two types One type is used with the cooling fan mounted on the engine The fan is belt driven by the crankshaft pulley in a two point drive The fan support bracket fan spindle and drive pulley are adjustable with respect to the crankshaft pulley in order to maintain proper belt tension The fan blades project into the radiator shroud which has sufficient tip clearance for belt tension adjustment The other type of set mounted radiator consists of an assembly of radiator fan drive pulley and adjustable idler pulley to maintain belt tension The fan is mounted with its centre fixed in a venturi shroud with very close tip clearance for high effic
42. the fuel level sensor the pump stops If there should be any overflow of fuel in the basetank the excess will drain back into the bulk tank via the return line With this system the basetank must include the overflow via the return line a 1 4 metre extended vent to prevent overflow through the vent sealed Figure 10 2 Typical Layout with Fuel System 2 The key components are the bulk fuel tank item 1 which is higher than the basetank remote fuel system controls item 2 located in the generator set control panel a DC motorised fuel valve item 3 fuel level switches in the basetank item 4 an extended vent return line continuous rise on the basetank item 5 the fuel supply line item 6 a fuel strainer item 7 and an isolating valve at the bulk tank item 8 When set to automatic the system operates as follows low fuel level in the basetank is sensed by the fuel level sensor The DC motorised valve is opened and fuel is allowed to flow from the high level bulk tank to the basetank by the force of gravity To help ensure that clean fuel reaches the engine fuel from the bulk tank is strained just prior to the motorised valve When the basetank is full as sensed by the fuel level sensor the motorised valve is closed Any overflow into the basetank or overpressure in the basetank will flow back to the bulk tank via the extended vent 14 With this system the basetank must include an overflow via the return line
43. uel Consumption US gal hr FuelSpec Weight Ib US gal FuelSpecific Gravity 8 34 Ib FuelCons US gal hr x FuelSpec Wt Ib US gal BHP Specific Fuel Consumption Ib BHP hr Spec Fuel Cons Ib BHP hr BHP Specific Fuel Consumption kg BHP hr Electrical Motor Horsepower kW Input x Motor Efficiency Electrical Motor Horsepower 0 746 x Generator Efficiency kW Output Required Engine Horsepower Required 0 746 x Generator Efficiency Piston Travel Feet Per Minute FPM 2x Lx N Where L Length of Stroke in Feet N Rotational Speed of Crankshaft in RPM BREAK MEAN EFFECTIVE PRESSURE BMEP 4 Cycle 792 000 x BHP BMEP Total Displacement x RPM 25 13 GLOSSARY OF TERMS ALTERNATING CURRENT A current which periodically reverses in direction and changes its magnitude as it flows through a conductor or electrical circuit The magnitude of an alternating current rises from zero to maximum value in one direction returns to zero and then follows the same variation in the opposite direction One complete alternation is one cycle or 360 electrical degrees In the case of 50 cycle alternating current the cycle is completed 50 times per second AMBIENT TEMPERATURE The air temperature of the surroundings in which the generating system operates This may be expressed in degrees Celsius or Fahrenheit AMPERE A The unit of measur
44. uency under constant load UENCY DROOP The change in frequency between steady state no load and steady state full load which is a function of the engine and governing systems FULL LOAD CURRENT The full load current of a machine or apparatus is the value of current in RMS or DC amperes which it carries when delivering its rate output under its rated conditions Normally the full load current is the rated current GENERATOR A general name for a device for converting mechanical energy into electrical energy The electrical energy may be direct current DC or alternating current AC An AC generator may be called an alternator HERTZ H7 SEE FREQUENCY INDUCTANCE L Any device with iron in the magnetic structure has what amounts to magnetic inertia This inertia opposes any change in current The characteristic of a circuit which causes this magnetic inertia is know as self inductance it is measured in Henries and the symbol is L INTERRUPTABLE SERVICE A plan where by an electric utility elects to interrupt service to a specific customer at any time Special rates are often available to customers under such agreements kVA 1 000 Volt amperes Apparent power Equal to kW divided by the power factor 27 kW 1 000 Watts Real power Equal to KVA multiplied by the power factor POWER Rate of performing work or energy per unit of time Mechanical power is often measured in horsepower electrical power in kilo
45. watts POWER FACTOR In AC circuits the inductances and capacitances may cause the point at which the voltage wave passes through zero to differ from the point at which the current wave passes through zero When the current wave precedes the voltage wave a leading power factor results as in the case of a capacitive load or over excited synchronous motors When the voltage wave precedes the current wave a lagging power factor results This is generally the case The power factor expresses the extent to which voltage zero differs from the current zero Considering one full cycle to be 360 degrees the difference between the zero point can then be expressed as an angle q Power factor is calculated as the cosine of the q between zero points and is expressed as a decimal fraction 0 8 or as a percentage 80 It can also be shown to be the ratio of kW divided by kVA In other words kW kVA x P F PRIME POWER That source of supply of electrical energy utilised by the user which is normally available continuously day and night usually supplied by an electric utility company but sometimes by owner generation RATED CURRENT The rated continuous current of a machine or apparatus is the value of current in RMS or DC amperes which it can carry continuously in normal service without exceeding the allowable temperature rises RATED POWER The stated or guaranteed net electric output which is obtainable continuously from a generating set when it is fun
46. wo configurations provides flexibility of installation such as horizontal or vertical above engine on outside wall etc The side inlet type permits 90 change of direction without using an elbow Both silencer configurations should contain drain fittings in locations that assure draining the silencer in whatever attitude it is installed The silencer may be located close to the engine with exhaust piping leading from the silencer to the outside or it may be located outdoors on the wall or roof Locating the silencer close to the engine affords best overall noise attenuation because of minimum piping to the silencer Servicing and draining of the silencer is likely to be more convenient with the silencer indoors However mounting the silencer outside has the advantage that the silencer need not be insulated though it should be surrounded by a protective screen The job of insulating piping within the room is simpler when the silencer is outside and the insulation then can aid noise attenuation Since silencers are large and heavy consider their dimensions and weight when you are planning the exhaust system The silencer must be adequately supported so its weight is not applied to the engine s exhaust manifold or turbocharger The silencer must fit into the space available without requiring extra bends in the exhaust piping which would cause high exhaust back pressure A side inlet silencer may be installed horizontally above t
47. y is not as objectionable in an isolated pumping station 7 1 Exhaust Silencer Selection The silencer reduces noise in the exhaust system by dissipating energy in chambers and baffle tubes and by eliminating wave reflection that causes resonance The silencer is selected according to the degree of attenuation required by the site conditions and regulations The size of silencer and exhaust piping should hold exhaust back pressure within limits recommended by the engine manufacturer Silencers are rated according to their degree of silencing by such terms as low degree or industrial moderate or residential and high degree or critical Low Degree or Industrial Silencing Suitable for industrial areas where background noise level is relatively high or for remote areas where partly muffled noise is permissible Moderate Degree or Residential Silencing Reduces exhaust noise to an acceptable level in localities where moderately effective silencing is required such as semi residential areas where a moderate background noise is always present High Degree or Critical Silencing Provides maximum silencing for residential hospital school hotel store apartment building and other areas where background noise level is low and generating set noise must be kept to a Silencers normally are available in two configurations a end inlet end outlet or b side inlet end outlet Having the choice of these t
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