British Ignition Components.
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A Visit to the " Prested" Company's London Factory.
In no part of a commercial motor is the necessity for the utilisation of the best materials, coupled with high-class workmanship, more important than in the ignition system. French coils, and accumulators, have, until recently, been supposed to be the only ones which could be relied upon, and, unfortnately, this stigma was not altogether unearned by our manufacturers. Another cause which, in a no inconsiderable degree, militated against large sales of electrical sundries, was the fact that many cheap batteries, coils, and other electrical details have been imported from Germany, and sold to the English customer, whilst bearing the name of an English house. The result was, as might have been foreseen, a disinclination to buy what were supposed to be goods of British manufacture, and a large increase in the sales of French coils, etc., which are undoubtedly well made in most instances.
One of our representatives recently inspected the manufacture of some of the types of accumulators and coils, marketed by the Prested Miners' Gas-lndicating Electric Lamp Company, Limited, of Elthorne Road, Holloway, N. The writer can say, after actual examination of all the various departments and processes, that the apparata sold by the company are made entirely at the factory. Raw material, brass, vulcanite, wood, and other substances are purchased in large quantities, and are, afterwards, machined to the requisite size and pattern. It would, obviously, be unfair to make public the various special means adopted by the makers to arrive at the state of perfection shown in the standard patterns.
The writer proposes to give a short description, in their proper sequence, of the various departments through which the parts of a coil have to pass before it is ready for delivery to the purchaser. The first operation is the making of a wooden case; in the coils under notice, teak wood is invariably used, as being an excellent material, and one which will withstand extremes of temperature. The cases for each distinct pattern are all made interchangeable. The next department is the trembler shop, where these parts are
machined by tools specially made for the purpose. It may be mentioned, here, that a " cut-out," working in conjunction with the trembler blade, can be fitted to all coils, if ordered.
The coil-winding shop is an interesting corner of the main building. The different layers of a coil are insulated from each other by a bed of fabric, the subject of a patent, and not by the more usual waxed paper. After the requisite number of layers of wire have been put in place, one upon the other, the unit is lowered into a bath of insulating composition, where it is allowed to remain for four or five hours, according to requirements. The condensers are prepared in the same department, and are dipped into a bath of liquid similar to that employed for the coils. The primary and secondary coils are next assembled, and the condenser is fitted into its proper position. The three portions are then put into the case which is destined to hold them, and an insulating mixture is, afterwards, poured over them ; this serves to bind all firmly together. The next step towards completion is the insertion of the iron core, formed from a bundle of soft iron wire, and the fitting on of the trembler blade. After the last process, the complete coil is thoroughly tested, in order to prove its efficiency and freedom from any fault. The final stage is the fitting of the unit into the teak case, which is beautifully finished, and dust and water tight.
The manufacture of accumulators is equally interesting, and would form an instructive lesson to those who only see the completed cell. The writer will shortly describe the different departments connected with the manufacture of accuImitators at the Elthorne Road Works, The primary operation is the casting of the grids, designed to carry the paste. The metal, from which the castings are made, is a mixture of lead and antimony, with an additional substance to give it greater strength. In practice, a little of the boiling metal is taken up in a small ladle ; it is then poured between the two halves of a mould. It solidifies almost immediately, and the portions of the mould are separated, after which the grid is extracted, and the same process repeated. The
rough plates, or grids, are next taken to a circular powerdriven saw, where they are trimmed to the size, and shape, required for the particular pattern of cell which they are to lit. The grids are now carried to the pasting department, where this material is forced into the small rectangular openings, or cells, in the grid, by means of a wooden spatula. About a dozen of the grids are next taken and put into a pressing machine, each with a thickness of woollen ci.3th between it and the next one. After the grids have been s.ibjected to a certain degree of pressure, they are taken from the machine and stacked in special racks for a period ef over three weeks for the paste to harden. It may, appropriately, be mentioned, at this stage, that a stock of plates numbering over to,000 is always kept for immediate use.
The filled grids are now taken to the forming room, where a steady electric current is passed through them for about 56 hours. The forming room contains a large storage battery, with a capacity of ',coo° ampere-hours.
The next shop is devoted to the construction of the celluloid cases, which are to contain the elements. This is an interesting department, and it is highly interesting to see. how the different parts of the cells are built up. The next step is the department wherein the required number of grids are assembled in a cell, and the lugs are inter-connected by a special process. It may, here, be mentioned, that the writer was shown several improved constructional details, which will be incorporated in the 19°7 models, but which he is, at present, not at liberty to describe. The cells, in this ;tage, are taken to the charging shop, where they are filled with the electrolyte (sulphuric acid, diluted with pure distilled water in a definite proportion) and put upon a charging hoird capable of holding upwards of 240 cells.
This pepetically finishes the various transitional stages through which an accumulator has to pass before it finally reaches completion ; but, it must be understood that only the barest outline of the constructional sequence of operations has been given. All the batteries made by the company have patent non-corrosive terminals. In addition to specialising in the manufacture of coils and batteries, the company makes all kinds of parts, such as : contact makers, charging hoards, terminals, and, of course, as mentioned above, every detail contained in the coils and batteries unade by them. The company may be justly proud of the finish and ail-round excellence displayed in its manufactures, and its productions merit the attention of both owners and manufacturers of commercial motors.