Generator sizing guide - Electrical and Industrial …

1 Technical Data TD00405018 EEffective April 2017 Supersedes August 2009 ContentsDescription PageTable 1. Motor load reference ..3 Table 2. Non-motor load reference ..4 Table 3. Surge capability ..5 Table 4. Fuel pipe sizing ..6 Table 5. LP vapor (LPV) tank sizing ..7 UPS Generator compatibility ..8 Table 6. Online estimating sheet ..9On-site estimating sheet ..10 Typical single-phase Generator /transfer switch combinations ..11 NEC (700, 701, 702) comparison ..12 Electrical formulas ..13 Weights and measures ..14 Generator sizing guide2 Technical Data TD00405018 EEffective April 2017 Generator sizing guide eaton noticeThis booklet is designed to familiarize estimators and installers with proper sizing guidelines for residential and commercial generators . The information is not comprehensive, nor does it replace or supersede any material contained in any of the written documents shipped with the equipment. This booklet should only be used in conjunction with the Owner s Manual, Installation Manual, and other technical documents shipped with each product.

2 Always read all accompanying documentation carefully before attempting to install any Generator , transfer switch, or related to use this bookletWithin this booklet, you will find Electrical load information, plus an outline of Generator surge capability, fuel pipe sizing , liquid propane tank sizing , and UPS/ Generator compatibility. The worksheet pages can be removed from the book and photocopied to create additional On-site Estimating Sheets for use with individual jobs. Safety informationProper sizing of the Generator is crucial to the success of any installation and requires a good working knowledge of electricity and its characteristics, as well as the varying requirements of the Electrical equipment comprising the load. When analyzing the Electrical load, consult the manufacturer s nameplate on each major appliance or piece of equipment to determine its starting and running requirements in terms of watts, amps, and voltage. When choosing the Generator output for commercial or Industrial applications, select a rating that is approximately 20 to 25% higher than the peak load (for example, if the load is about 40 kilowatts, select a 50 kW genset).

3 A higher rated Generator will operate comfortably at approximately 80% of its full capacity and will provide a margin of flexibility if the load increases in the safety reasons, eaton recommends that the backup power system be installed, serviced, and repaired by an eaton Authorized Service Dealer or a competent, qualified electrician or installation technician who is familiar with applicable codes, standards, and is essential to comply with all regulations established by the Occupational Safety & Health Administration (OSHA) and strict adherence to all local, state, and national codes is mandatory. Before selecting a Generator , check for municipal ordinances that may dictate requirements regarding placement of the unit (setback from building and/or lot line), Electrical wiring, gas piping, fuel storage (for liquid propane or diesel tanks), sound and exhaust you have a technical question regarding sizing or installation, contact EatonCare s Technical Resource Center toll free at 1-877-386-2273, option 2 during normal business hours (8 to 4 CST).

4 3 Technical Data TD00405018 EEffective April 2017 Generator sizing guide eaton 1. Motor load referenceac and heat pumpsRunning loadStarting loadDescriptionhpRunning kWSingle-phaseThree-phaseSingle-phaseThr ee-phasekWAmps at 240 VAmps at 208 VAmps at 240 VAmps at 480 VLR amps at 240 VLR amps at 208 VLR amps at 240 VLR amps at 480 V1 ton (12,000 BTU) ton (24,000 BTU)22107636744381953 ton (36,000 BTU)331510841006758297. 54 ton (48,000 BTU)442013116117786734105 ton (60,000 BTU) ton (85,000 BTU)7. 57. 537242111219146126631710 ton (120,000 BTU) a5 (x2) ton (120,000 BTU)10104933281425016714 4722015 ton (180,000 BTU) a7. 5 ( x 2 )1574494221219146126631715 ton (180,000 BTU)1515744942213752502171083020 ton (240,000 BTU) a10 (x2)209865572825016714 4722020 ton (240,000 BTU)2020N/A65572850033328914 44025 ton (300,000 BTU)2525N/A8271356254163611805030 ton (360,000 BTU) a15 (x 2)30N/A9885423752502171083030 ton (360,000 BTU)3030N/A9885427505004332176040 ton (480,000 BTU) a20 (x2)40N/A1311135750033328914 44040 ton (480,000 BTU)4040N/A1311135710006665772898050 ton (480,000 BTU) a25 (x2)50N/A163142716254163611805050 ton (480,000 BTU)5050N/A163142711250833722361100 General residentialDescriptionhpRunning kWSingle-phaseSingle-phasekWAmps at 120 amps at 240 VLR amps at 240 VLR amps at 120 VRefrigerator pump, sump, furnace, garage , washer, septic 1 and septic lift For multiple motor configurations, sequence starting is CAUTIONDO NOT SIZE THE Generator BASED ON STARTING KW MUST COMPARE LR AMPS TO Generator SURGE CAPABILITY (TABLE 3).

5 SIZE THE Generator BY FOLLOWING THE sizing Data TD00405018 EEffective April 2017 Generator sizing guide eaton 2. Non-motor load referenceResidentialDescriptionRunning load aRunning kWSingle-phaseAmps at 120 VAmps at 240 VElectric heat per 1000 ft212N/A50 Heat pump elements per 1000 ft27 tub10N/A50 Range oven/stove top per burner8N/A30 Hot lighting and receptacles per 1000 entertainment refer to equipment data plate and/or billing history for commercial Always check data plate for actual running Data TD00405018 EEffective April 2017 Generator sizing guide eaton 3. Surge capabilityGenerators (operating at less than 3600 RPM)Size (kW)Rated output (running amps)Commercial (LR amps at 15% voltage dip)Residential (LR amps at 30% voltage dip)Single-phaseThree-phaseSingle-phaseT hree-phaseSingle-phaseThree-phase240 V208 V240 V480 V240 V208 V240 V480 V240 V208 V240 V480 V229276N/AN/A7148N/AN/A13492N/AN/A251048 7753871484630138929159271139481411006758 3315 3137118643012510490451006765432051371308 7351461211055211375604322515011887361501 2510854113756544225151131874016713912060 1298675492541691479745188156135681469894 572921951681124820016714 4721631099457321214185112702922432101052 7516415995550330318190803332782401202751 8315910655036631821210041734730015036922 22141287384 4142625513054245139019554636431520910887 24628419 generators (operating at 3600 RPM)

6 729N/AN/AN/A23N/AN/AN/A46N/AN/AN/A833N/A N/AN/A26N/AN/AN/A51N/AN/AN/A1042N/AN/AN/ A31N/AN/AN/A63N/AN/AN/A1354N/AN/AN/A48N/ AN/AN/A95N/AN/AN/A1458N/AN/AN/A52N/AN/AN /A102N/AN/AN/A1667N/AN/AN/A59N/AN/AN/A11 7N/AN/AN/A1771N/AN/AN/A63N/AN/AN/A125N/A N/AN/A1875N/AN/AN/A67N/AN/AN/A133N/AN/AN /A2083N/AN/AN/A73N/AN/AN/A145N/AN/AN/A25 1048775387148463013892916030125104904510 0676043205137130873514612110552113756043 2251501188745188156135681469894572921951 6811260250208180901791201036935023420413 6702922432101052751641429555033028619080 33327824012027518315 8106550366318212100417347300150369222214 1287384 4142625515062552045122655837232221511217 47647431otee:NAll nominal ratings based upon LP fuel. Refer to specification sheet for NG ratings and deration adjustments for ambient temperature and Data TD00405018 EEffective April 2017 Generator sizing guide eaton 4. Fuel pipe sizingNatural gas (values are maximum pipe run in ft)kWPipe size (in inches) 85520082010208537080013 14105024554516 1740190425202013030594522151152607992510 952207392785203552306014756535 3635953709154025753157904515602606504850 23058550502205606025145390118 5705752257108065195630100401404601305021 515030150LP vapor (values are maximum pipe run in ft)kWPipe size (in inches) 81655701070255100013 144517069016 1725130540201511548022853652560275605275 5260575304019543535 3620125290103040151072508904582195725487 0165620507016061060451154451095702060260 6608015502305901003016543013051307020566 015045150490LP LPG: ft3/lb, lb/gal, 2500 btu/ft3 LPG: ft3 = 1 gal Natural gas 1 cubic foot = 1,000 BTU 1 therm = 100,000 BTU Gas consumption = 13,000 16,000 BTU per kW/hrPressure 1 inch mercury = inches water column 1 inch water column = psi 5 14 inches water column = psi to psiNotee.

7 Pipe sizing is based on in H2O pressure drop sizing includes a nominal number of elbows and tees Please verify adequate service and meter sizing7 Technical Data TD00405018 EEffective April 2017 Generator sizing guide eaton 5. LP vapor (LPV) tank sizingVapor withdrawal (dimensions are given in inches)Tank capacity total (gal)Tank capacity useable (gal)Minimum temp ( F)Tank capacity (btu/hr)LengthDiameterOverall height1207240200246,240164,16082,0805724 331509040200293,760195,8409 7, 9 2 068243325015040200507,600338,400169,2009 4303932519540200642,600428,400214,200119 303950030040200792,540528,3602 6 4,18 01193746850510402001, 2 17, 7 0 0811, 8 0 0405,90016541501000600402001, 416,9 6 0944,640472,3201924150 Load (kW)BTU/hrLP gal/hrNG ft3/hr NG therms/hr5110, , 31,8 0 , , , ,4005 . , ,0007. , ,035,700111,0 2 ,170, ,15 ,200,000131, 2 0 ,280, , 2 6 ,550, ,5 5 ,675, ,6 ,800, ,78 617. 81401,925, , ,050, , ,800, , ,100, ,10 :NOperating cost per hour = NG therms/hr x cost of NG required for common appliancesApplianceApproximate input (btu/hr)Warm air furnace Single family Multifamily, per unit100,00060,000 Hydronic boiler, space heating Single family Multifamily, per unit100,00060,000 Hydronic boiler, space and water heating Single family Multifamily, per unit120,00075,000 Range, free standing, domesticBuilt-in oven or broiler unit, domesticBuilt-in top unit, domestic65,00025,00040,000 Water heater, automatic storage, 30 to 40 gal.

8 TankWater heater, automatic storage, 50 gal. tankWater healer, automatic storage, instantaneous 2 gpm 4 gpm 6 gpmWater heater, domestic, circulating or side-arm35,00050,000142,800285,000428,00 035,000 RefrigeratorClothes dryer, Type 1 (domestic)Gas fireplace direct ventGas logBarbecueGas lightIncinerator, domestic3,00035,00040,00080,00040,0002,5 0035,000otee:NTank BTU capacity and Generator run times based upon maintaining a minimum tank fuel level of 20%. Tanks are typically filled to 80% full. Typical fuel consumption based on a Generator 100% Data TD00405018 EEffective April 2017 Generator sizing guide eaton Generator compatibilityPassive (also referenced as standby or offline) and line-interactiveThese technologies are most common for personal workstations and point-of-sale applications. They are typically single-phase equipment with size ranges of 350 2000 VA for passive and 500 VA to 5000 VA for UPSs are the simplest type.

9 Under normal conditions, ac power passes straight through to the UPS load. When the input power supply goes outside of specifications, the UPS transfers the load from input power to the internal dc to ac power inverter. Passive UPSs do not correct for voltage or frequency deviations under normal is similar to the passive technology except it has circuitry that attempts to correct for standard voltage deviations. Frequency deviations under normal power operation are not notesThese devices tend to be electrically/harmonically very noisy. A single small UPS is not a significant concern, but applications with multiple UPSs can be UPS technology typically has normal tolerances of 10 25% on voltage and 3 Hz on frequency. If the input source goes outside of these tolerances, the UPS will switch onto the UPS battery source. Some line-interactive units may have frequency tolerances factory set to Hz. These units will need to have their frequency tolerance increased to a minimum of 2 sizing recommendation Limit the total UPS loading to 15% 20% of the Generator capacityDouble-conversionThis technology is most common for critical load applications.

10 Double-conversion UPSs constantly rectify ac to dc and then invert the dc back into ac. This configuration results in an output that corrects for voltage and frequency are single- and three-phase models covering small to large applications. Most UPS applications larger than 5000 VA use double-conversion technology. This approach is also the preferred technology for Generator notesDouble-conversion UPSs that are single-phase or unfiltered three-phase models tend to create a significant level of Electrical / harmonic noise. This is illustrated by harmonic current distortions that are greater than 35%. Minuteman UPS products could have current distortion of 8%. When three-phase models are supplied with harmonic filters (current distortion less than 10%), this concern is no longer an sizing recommendations Single-phase models: Limit the total UPS loading to 25% of the Generator capacity Single-phase Minuteman UPS models: Limit the total UPS loading to 50% of the Generator capacity Three-phase models without filters (current distortion > 30%): Limit the UPS loading to 35% of the Generator capacity Three-phase models with filters (current distortion < 10%): Limit the UPS loading to 80% of the Generator capacitySupplier(s)Passive (standby)Line-interactiveDouble-conversi onPowerware3000 series5000 series9000 seriesMinuteman UPSE nspireEnterprise PlusEndeavorAPCBack-UPS SeriesSmart-UPS SeriesSymmetra SeriesLiebertPowerSure PST & PSPP owerSure PSA & PSIUPS tation & Nfinity9 Technical Data TD00405018 EEffective April 2017 Generator sizing guide eaton 6.