Document n9Enybe90aKYvzp81ZQyn9av1

V-Belt Drives (Continued from page 126) type ond characteristics of the drives 'if* machine. A shock load of a crusher ro> H quires more reserve horsepower capte*'. ity in the drive than a smoother oper?Veiing unit like a pump or compressor." $ When in doubt it is better to overboil* *$f then to underbelt a drive. ?jOverload Capacity. Characteristic of primo mover and driven msehins'Ijol must -be taken into acoount when <}e.:;.*5 termining the necessary overload ea.iu$ pacity that a drive should have to glv*' satisfactory service. From these cnsid.'-',i(3 erations V-belt engineers provide serv> ice factors that indicate the overload:^ capocity to odd to the nominal driver. .> horsepower in each cose. Service factors --] irecommended by the V-belt manufse* tuier give the horsepower capacity r* quired hr the application in quciiica.*"^* Confer Oiitancs. Center distance o V-belt drive is important. The gen-.','$[ eralty accepted rule is that the ideal :?i center distance is between 1 and times <hc diameter of the larger sheave. * Use of the shortest centers whenever possible insures use of the shorter pitch length belts. These are not only tower )&! in first cost ond: for replacement bul'-*A also in maintenance. A short-center dij-. .. ` lance, therefore, is important in facet ing the most economical drive. All these points must be-considered carefully in engineering a drive. The-,^ most economical uses the proper seelion V-bcits so a minimum number prev* Hffvide the total horsepower-transmiuiaii^i} capacity of the drive. Sheave diameters *'?will be large enough to insure good belti/ lift, yet not to large .as to give'excessive **'^ speed. If one sheave, is larger than the other, the lesser arc of contact on be.'/?' smaller aheave must be taken into sc- ,v} count. Center distance will be.as short;,,^ as practicable. Last but not least, lke,,. r '&service factor prescribed for the sppU- cation must determine the number belle necessary to transmit the actual horsepower required. Horsepower. Certain salient help in selecting belts and sheaves go to make up the most economical. ^ drive. First is a belt-selection table ihs*^'* most manufacturers publish. This si-. ply recommends the belt section different speeds with various-sited tors. Dated on nominal horKpo*eris a result of experience in1 thousands of drives. While there be exceptions its recommendations practically alwoys bo followed. At css^ it provides a starling point in POWER December There could bo tome excessivo operating coats hidden in an antiquated or Inadequate coal or ash handling system. To bo eh tho sole tide, check the many proven time and.labor sav ing advantages offered by Asystem of this kind, planned by Fairfield, is designed, bail! and erected especially to meet the operating -and physical requirements of your plant. Fairfield Engineers, specialists In the planning of Coal and Ash Handling systems, and with many years of practical ex perience back of them; are at year service. Why net call one In for an analysis of your requirement^T Write for Catalog No. 144-A. i bviker to put*vUm. Two-Too moaor Srtwo vd|k Urrf terviaf four bolhn. The FAIRFIELD ENGINEERING COMPANY BUILDERS OF DEPENDABLE COAL AND ASH HANDLING EQUIPMENT 327 CHICAGO AVE. MARION, OHIO, U. S. A. Oscembor 1948