MICROFICHE REFERENCE LIBFUUW - Cd3wd.com

151electricity), the amount of use (i.e., both lift time and running intervals),user’s preference, and power requirement. The following is a commonguide to selectionby power size:less than 7-l/2 hp -- gasoline engine or electric motor7-l/2 - 40 hp -- gasoline or 3-phase electric40 - 150 hp -- gasoline or diesel (diesel if more than1000 hr/yr)more than 150 hp -- dieselOne aspect of user’s preference is the ability to obtain skilled attendantsto operate and maintain these mechanical drivers. This is a particularlycommon problem in developing countries (Molenaar, 1956).Among the basic transmission components are: V-belts, flat-belts,gears (parallel and angle), silent chains, hydraulic-fluid couples, frictionclutches, flexible-shafts (e.g., universal joint). A common arrangementfor driving a vertical turbine pump is with an engine through a standard,right-angle, pump head transmission. Of course, where the engine or motor,and pump speeds are matched, they can be operated withouta transmission,i.e., close-coupled. Another form of transmission, but usable with onlya few specialized water lifters (e.g., submersible centrifugal, air-lift,and diaphragm), is compressed air. It, in effect, transmits power from acompressor engine to the lifter, Hydraulic fluid can be similarly usedin some applications (see Mexican solar pump in Section 5.2.3.3) .For drivingmodern pumps, mechanical prime movers have been the primarysource of power. However, the changing world energy situation is causingmany consumers to improve mechanical operations and/or consider natural energysources to drive their water lifters , particularly in developing countries.