THE SPHERE OF THE COMMERCIAL ELECTRIC.
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By F. Ayton, M.I.E.E.*
E ELECTRIC VEHICLE, in its strictly de
lined and H lined and limited sphere of utility, has econo
mies and other advantages such as will, with certainty, ensure an extensive deurand for it. As one who, for some years, has studied this question very closely, and who has for a long time been an ardent petrol motorist, I would say that I see no possibility of the electric ousting the petrol vehicle in any sphere but that of short-distance, frequentstop work, with perhaim one exception. Experience already indicates that toeach particular-type of motor vehicle, petrol, steam, and electric, belongs a fairly well defined sphere of utility in which its inherent characteristics and merits indicate it to• be the best and most economical to employ. The electric is essentially a moderate-speed vehicle, i
and its radius of action s limited by the mileage which can be obtained by the supply of electrical energy contained in the fully charged battery. For example, a three-ton lorry fitted with the.usual size of battery will cover from 35 to 40 miles on one charge, given fairly level and good surface roads. Put such a vehicle to work on a route which is very hilly, or where roads are bad, and the mileage per battery charge is decreased maybe to a considerable extent. This characteristic of the electric clearly limits its
sphere of useful application to short-distance work, and we may otherwise describe this sphere as, generally speaking, lying within the confines of urban and suburban districts. When stops are frequent, as in town delivery and collection, and where busy thoroughfares have to be negotiated, there are other advantageous features of the electric which make it specially suited for such service. I refer to its ease of manipulation, due to the absence of any " change speed' gear, to its high rate of -acceleration, to the automatic cessation of power coetsureption when standing, and to the self-starting characteristic of its power unit.
A careful consideration of the characteristics of the commercial electric must inevitably lead to the conclusion that its main field of 'application lies in substitution for horse haulage. It does not and.cannot compete with the petrol vehicle where the latter is employed upon work for which it is so well suited, Which is, of course, long-distance haulage and express service.
To the electric 'belongs the distinction of having changed the economic position of the horse within the environs of ;town and city. The petrol vehicle finds its sphere largely in performances which are impossible for the horse ; the •electric, on the other hand, on the basis of working cost, convenience, and-dependability, enters into competition with the horse, and will rapidly displace him. I have mentioned an exception to the general rule advanced above as to the field of utility of the electric. While the development may not take place yet awhile, .1 foresee the time when, with the establishment of charging stations at frequent intervals along all our main roads, electric road transport services between towns will be inaugurated for goods in connection with which the time taken for transit is not of first imp artance. The advent of that development will be materially hastened by the adoption of a system of inter-changeable batteries. Inter-changeability of batteries connotes standardization of battery boxes and means of supporting same from the chassis.
It has often been asserted that the electric vehicle is too slow. It is true that it is a moderate-epeed machine, and, quite apart from the limit of its radius of action, this characteristic in itself militates against competition with the petrol vehicle for longdistance work. But in the sphere for which it is proved to be suitable, high maximum speed gives little, if any, advantage ; indeed, from the point of view of safety, it is a distinct disadvantage. In traffic the rapid acceleration of the electric gives it an appreciable advantage over the petrol type. enabling it to get from point to point quite as quickly. The results obtained by Harding's Royal Steam
Bakery, I3irmingham, in the application of electric. vans for bread delivery go to prove the fallacy of the contention that the electric is wanting in speed. The first electric 30-cwt, van acquired by the firm was put, on to a round that had up to then been covered by a modern type-of petrol van of the same size. The work comprises a round of 11i miles, with some 50 delivery stops, which is covered three times per ordinary. week-day and four times on Saturday. It was found that, compared with the average time taken by the petrol vehicle to do the trip, a saving of 30 minutes per trip was made by the electric. It may be mentioned that the weekly cost of electrical energy for. this vehicle averaged 13s. 4d., while the cost of petrol for the vehicle previously in use averaged 22 10s. In 1917 Mr. J. A. Priestley, of Sheffield, Made some careful tests over a,measured mile in order to weer-, tam n the travelling time, with a definite number of stops, of three types of vehicle, i.e., horse-drawn vehicle, petrol wagon, and. an electric wagon. The petrol and electric -wagons had each a capacity of two tons. The former was a 20 h.p. car of one of the best makes, and the latter an Edison vehicle. The horse vehicle consisted of a single horse drawing a four-wheeled covered wagon. Two tests were made, " A " being with a stop every 10 yards, and " B " with a stop every 20 yards. The times taken for covering the distance of one mile were as follow :—
As has been stated already, the greatest development has taken place in the United States, and comparatively few people on this side of the Atlantic appreciate the extent to which electric vehicles are employed in the large cities and towns in that country. It is computed that the number of electric vehicles of all types in use there is over 70,000. In 1917 it was stated, as the result of inquiries made, that in round figures the new vehicles sold during the previous year totalled some 8,000, of vz:hich approximately 2,500 were of the commercial type. The remainder consisted of about 4,000 cars of the private passenger-carrying type, and about 1,500 inatistrial trucks.
In this country the adoption of the electric for commercial purposes has, considering the difficulties due to the -war, made fair progress. Among the largest users are the Midland Railway Co., Messrs. Harrods Ltd., London, and Messrs. Joseph Lyons, Ltd., London. I_ am convinced that it will not be long ere our large cities, particularly London, will be served by electric taxicabs. It is noteworthy that in the very home of the petrol car in the United States, viz., Detroit, the Detroit Tax-cab Co. has for some years been gradually replacing its petrol taxis by electric ones, The first of the latterwas put into use in June,. 1914. By 1918 the number of
electric cabs put into service by this company was in the neighbourhood of 100, and schemes were afoot, as the result of the great success of electric cabs in Detroit, to establish electric taxicab fleets in New York and other great cities in the States. Witkelectrio taxis built, as they are to-day, to run at maximum speeds of 25 miles per hour, and with a range of action of from 60 to 75 miles on one charge, it must be obvious that there is an opening for their extensive employment. though some of the earliest electric vehicles were constructed in this country, they were, with one or two exceptions, not of the commercial type. Within the last few years, however, certain British engineering firms have taken up the manufacture of these machines, and it is satisfactory to be able to say that at the present time commercial electric vehicles are being built in this country which compare most favourably with the best makes from America.
In the design of commercial electric vehicles, it is important to eliminate friction to the greatest possible extent, and to provide for moderate speeds only. As to the most suitable speeds, those given in a paper on electric vehicle standardization, read a few years ago before the Electric Vehicle Association of America, may be taken as a fairly good guide:— The Glasgow Corporation Electricity Department was among the first to adopt the modern type of commercial electric vehicle. Their first vehicle was a 1-ton van with a Detroit chassis and an Edison battery. It was pit into service in April, 1913, and up to tire beginning of last December had run 35,193 miles. During this time the motor had received no repairs whatever beyond renewal of brushes and varnishing of the armature and field coils. Similarly ii-ton lorry and two 5-ton tipping wagons for carting ashes, have run respectively 14,506, 14,094, and 15,574 miles, up to December last, without requiring any repairs to the motors. The speeds for which electric vehicle motors are usually designed vary from 800 to 1,700 r.p.m., the actual speed in any instance being dependent upon the type of drive employed and the gear ratio selected.
In America the large business connected with the manufacture of electric vehicles has been built up by co-operation between the firms constructing the vehioles and the electrical manufacturers. The design and manufacture of electric motors and switch gear is work that, speaking generally, specialist firms only can undertake with success. It is certain, therefore, that automobile builders who are proposing to take lin the construction of electries will find it to their aavantage to leave the manufacture of the motors and switch gear, as 'well as the supply of batteries, in the hands of those who are already engaged in slich work. Working upon such lines, there ought to be no difficulty in the way of any automobile builder taking up the-constructIon of the electric, seeing that much of the chassis work is very similar to what he is already providing for petrol vehicles.