Document ZBLRLpBxQZgBr55JQw5R4ZXa7

r Vector Analysis KXHAUST AND INTAKC LAYOUT: Plan and section* show th fitter* of the new 3850-hp enQlno and the future unit. This, ,, houtina for woste-heot boiler*, exhaust muffler*, end intake setup aivas operator* convenient access from operating floor* the plant to Install one 3850-hp engine end another similar machine for which specifications are out. In selecting the new engine, consider ation was given to larger cylinder bore but in view of the advantages of having unite as nearly alike as possible, we chose e 21%x31-in. 225-rpcn 2-cycle Nordkerg diesel direct-connected to an Elliott 3390-kva 6900-7200-v 3-phase 60-cycle generator. The present 21x29* in. engine (2250 hp) will be converted to 21^-ln. bore, and, since the new unit duplicates the 1941 engine, a measure of ring and piston*head standardization will be effected. Accessories. Completing the new in stallation are: 1836-sq*ft 150-psi Foster Wheeler extended-surface waste-heat boiler, Maxim exhaust and intake si lencer, Struthera-Wells oil coolers and jacket-water best exchanger, two AllisChalmers 965-gpm soft-water circulat ing pumps, Blockmer auxiliary oil pump, DolHnger Staynew automalio air filter. New building extension is 54x57% ft (cranewsy) plus an additional 25 ft, 3-In. extension to rear which houses waste-heat-boiler and muffler rooms, air-intake silencer end filter rooms at basement and operating-floor level Ad ditional apace above provides lockers sod washroom, chief operator's office and an entrance foyer. A balcony at crane-rail level provides space for cool ing-water surge tanks, sir-starting bot tles, day tanks, etc. Experience with an arrangement not particularly favorable to operation led us to take pains in designing the wasteheat-boiler and air filter layout. As shown in the drawing, operator* have easy access from basement and oper ating floor to the boiler room. Door* from boiler and muffler room into each section of filter and silencer rooms make these compartments readily avail able. In the past, mow entrainment in air entering the filter rooms was con siderable, the snow covering the fillers. Now If this happen*, we will open doors between filter and muffler rooms and bot air will prevent icing on screens. Houls louvers on the intake will also help. Similar louvers used in revamp ing the 4-cycle Intakes can be seen un der the windows in photo of baildiog front The 1941 and 1948 engines are airinjection units, for which wo find ad vantages when heavy oils ore burned. We now use itraight-run residual from Michigan refineries, with a viscosity of 500 to 1000 asu at 100 F. We are burning about 7000 gal per day. Total atorage capacity is 770,000 gol: 420,000 in a tank above ground, in the hills and 3SO.OOO in three tank* buried in sandy toil near the plant (see photo). The sand is not particularly corrosive; tanks ore stiffened by specially designed an nular angle-iron ring* inside, to carry the sand load. Burying the tanks not only improves plant appearance, it .helps reduce amount of heating neces sary to keep the oil fluid. There is also an 8000-gal underground lubricating- oil storage tank close to the plaal-| Fuel Oil. Wo hove given consider-jt oblo study to handling and burning oer:$ heavy fuel, which has s pour point ol J 34 to 42 F. Besides heating the ad^l jacem municipal water 6ltration pleat;! and an electric-distribution serving building to be erected, steam fieoj waste-heat boilers bests the fuel oiL r AH fuel piping I* insulated and soil-J heating cable run* parallel with piping jj under the insulation, ft is used to heat I oil.in an emergency. Two Shupln! centrifuges clean all fuel oil It *1*1 passes through Nugent filters, and h ] heated and settled in conical-bottoms tanka before going to tho engines. Alii lube oil goes through Honsn-Crane sod I Youngstown-MUier earth-type filter*. -1 After instelling the next unit, as pm-a vtded for in the building extension, for ther expansion must be handled by replacing the older 4-cycle engines with large 2-cycle uolts, as on the plan (F? ceding page). This would permit 1 creasing total plant ' horsepower ts obout 23,400. These older engines sr still going strong, however, and whs is done will depend on future load coo .dltions and tho fuel market. jj, Grand Haven power system is optf ated separately from other city seth ides by s board of five elected Iocs business men serving staggered terms. Separate accounting gives accurate record of all operations system's own organization handled engineering and construction of to recent extension. !, n (4*4) POWER Avgust VA (b) 1. Anglo batwoon voltogo end currant Is decraosed os power feetor Improves Parallel Operation Of Ac Generators Here'g how machines pick up and distribute load after syn chronizing. E J Kelley gives clear analysis of what happens to current and power factor if dc field and power output vary 3 ' ,,e,d * B um currant How through both generators 'WiB . Acgwt (448 * Parallel oprratioh of generators means that two or more unite, connected to the eame bus, supply power to tho load. In parallel operation of dc ma chines, load division between them Is handled by varying field rheostats. Since voltage varies with field strength, machine with highest voltage takes larger load. This is not true In parallel operation of ae generators. Fandomentsl*. Let's start our analy sts of a'c units by considering a single generator connected to the bus and supplying power to load. A 3-phase machine is shown schematically In Fig. la, and vectorially in lb. Sinee load ia generally balanced between the three phases of generators met with in or dinary practice, we wii) analyse what happens In but one phase. No attempt is made to keep vectors to scale. Let's look further at Fig. lb. Tho two vectors represent Une-to-neutral voltage V, and current in one phase winding, /. Since the majority of in dustrial loads are inductive, -current lags voltage as shown, ff load were purely resistive, both vectors would be (46$) rr