ELECTRO-FARMING

Evening Star, Issue 19781, 3 February 1928, Page 2

ELECTRO-FARMING

SUITABILITY OF INSTALLATION GRAPHIC TABLES PREPARED When farmers are approached with a view to persuading them to use electricity, they are found in general to be appreciative of the value of electric lighting, uninformed as to the nature of the electric motor, and quite ignorant of the possibilities of domestic appliances. The need for education in these matters is apparent. lint many farmers are receptive oi ideas, and when the multitudinous possibilities of electricity on the farm arc explained they quickly perceive its advantages. Which conditions arc tho most favorablie for the levelopmont of r. electrification!' Cereal production d mands generally Hat open country and a dry climate, and a soil which might bo deenbed as being of medium quality. Too rich a soil is not the best tor this purpose. Tho only nso of electricity in such areas would be for ploughing;this would necessitate tho construction of distribution lines capable of supplying large amounts of power wherever ploughing is to bo carried out. To bo economically possible, however, the same field would have to he ploughed year after year. Such considerations as crop rotation or adverse seasonal conditions prevent this. Ploughing for cereal production is therefore not likely to bo carried out by electrictiy. .Harvesting operations can, on the other hand, be carried out by using electric power. lint cereal growing country is usually also pastoral or stuck breeding country.; medium land values prevail. Although farmers in such areas may be prosperous,, their wealth is dependent on their holding large tracts of country and employing little labor. Tho distances between homesteads becomes very much greater than in areas where rich soil predominates. The tost of distribution is increased by the distances separating potential loads. The co-operation between neighbours essential 1o the success of such schemes becomes increasingly difficult to obtain; little, if any, development may bo expected in this class of .country. Milk production offers the best field for rural electrification, llich pastures are divided into small blocks and are closely populated; the cost of distribution is comparatively low. A _ small amount of power can be used daily for pumping, driving milking machines and separators. Motors can be used ,for silo filling and fodder cutting; electric light is an asset during milking operations in the winter time. Further, dairying districts usually include a number of butter or milk treatment faetpries which, tend to facilitate the extension of transmission systems. Under whatever system of tariffs a farmer may be supplied with electrical energy, he taust pay in proportion to his maximum demand. The energy consumption or load factor will generally be very low, the capital cost of distribution very high. _ The power station engineer will probably reason that it would be preferable for the farmer to uso smaller amounts of power for longer periods, or at a better load factor. The farmer has not done this and the engineer may deplore the conservativeness of the farmer or of the implement maker. The difficulty is of a different nature, as is illustrated by the following examble :

Consider a chaffcutler driven by a 4 h.p. motor and used for half an hour daily, consuming, say, 1 kw.-hr. It is clear that if a 1 h.p. motor could be used for two hours daily to do the same work, the same amount of electrical energy would he used, but tho load factor would be four times bettor. This would, of course, suit the electrical engineer, but would it suit tho farmer? A chaff cutter must he attended to. Assuming the cost of labor to be Is 6d per hour, and that electricity bo charged for at Od per kw.-hr, tho following would be tho net result to the farmer: — CASE I. —4 h.p. Motor Used for Half-hour.— Cost of electrical energy ... Os 6d Cost of labor ... , 0s 9d Total cost ... ... Is 3d CASE H. —1 h.p. Motor Used for Two Hours. — Cost of electrical energy ... Os 6d Cost of labor ... ... 3s Od Total cost 3s 6d It is apparent that even if electricity were available at a lower cost due to an improved load factor, it would still pay the fanner better to use tho higher power machine. In the writer’s opinion the above example illustrates why the use of electricity for ploughing purposes is not an economical possibility unless large amounts of power are used; yet the electrical engineer’s natural dislike for a load with a high demand and poor load factor has led him to persist unsuccessfully in attempts to develop ploughing by electricity, using motors of low rated output. Obviously other examples could be chosen in which the machines considered would require varying amounts of attention. Thus a pumping plant may be started or stopped automatically by means of a float switch; for such a plant it is a definite advantage to both farmer and supplier to adopt the smallest amount, of power practicable. The tariff consisting of a fixed charge and an energy charge is certainly the most equitable, providing the fixed charge is not too high. The diversity between motors used for farming purposes is usually greater than that between motors used.in towns. Suppliers can therefore afford to offer lower fixed charges than in the towns, hut should maintain a higher energy charge, the losses in distribution in rural schemes being notoriously high. Such a tariff is more readily accepted by the farmer. Assume a tariff consisting of a fixed charge of 5s per h.p. per month and an energy charge of 2d per kw. hr., and consider how far such a tariff encourages the farmer to reduce the power required to drive his machines. If he uses a 1 h.p. motor for two hours daily consuming 1 kw. hr., the cost per month will be 10s; if he uses a 4 h.p. motor for half an hour daily, consuming 1 kw. hr., the cost per month will bo 255. He will, in the latter case, have increased the cost of electricity two and a-half times. However, his labor cost will have decreased from £4 10s in the former case, to £1 2s 6d in the latter. ,

In the case considered'the increase in tho cost of labor due to adopting the smaller power has been more than three times the saving in the cost of electricity. If instead of the case of a 4 h.p, motor, that of .a 20 h.p, motor bo

considered; it is found that the farmer would be just as well off by miming his machine with a 5 h.p. instead of a 20 h.p. motor, but for periods four times as long. With a, 20 h.p. motor run half an hour per day, with attendance, the cost would be ns in table 1.

From this example it is clear that unless a machine takes at least 20 h p per man inquired to attend to it the tariff outlined offers no inducement to the farmer to so modify his machinery that it absorbs less power. Hence at the present time no such modification can be stimulated by tariffs for electricity since no agricultural machine in general use absoibs as much as 20 h.p. per man required to attend to it. - It is clear, therefore, that labor con-siderations-will tend to outweigh the cost of power in influencing the design of machines. The remedy is obviously to endeavor to render the machines as far as possible automatic; electricity lends itself particularly well to tills. It should not lie impossible nor even difficult to construct such machines as a chaffeuiter in such a way that a man is not required to attend to it. More difficult mechanical problems than this have been presented and solved in constructing agricultural machinery. With a 5 h.p. run two hours per day, with attendance, the cost would be as in table 3. TABLE 2.

TABLE 1. J’er £ Eised charge 5 Energy charge ... 1 Labor , Month, s. d. 0 0 5 0 2 6 Total ... 7 6

Per Month. £ 8. d. Fixed charge ... ... 1 5 0 Energy charge ... 1 5 0 Labor ... ... ... ... 4 10 0 lotal st]M , ... £7 Q Q