About "the Purr"

NZ Truth, Issue 1029, 15 August 1925, Page 16

About "the Purr"

"SECRETS" EXPLAINED— A CAR'S HER HISTORY

The Magneto's Magnets

In this article the writer tells, history" of contrivances that a pert, a mystery to the amateur

■;•••: As-.its, name implies, the magneto is something to do with magnets, and its magnets are of the permanent type, with a "magnetic' field" always present, whereas m a dynamo several hundred revolutions of the armature are required before the magneto field is built up. . The breaker box >is where the "make and break" takes place; that is to say, the primary current is made and broken TWICE each revolution. The current generated m the armature is taken by a "brush" which bears on an insulated ring, which, m its turn, is carried on an insulated spool; the latter is mounted on jthe driving end of the armature shaft. The distributing brush takes the current from the distributor, which revolves at half the armature shaft speed to the various contact points progressively, and thence to the plugs m the correct "firing" order. More difficult details are not given here, as the elementary points are all that can be conveyed m an article of this kind. THE CAR BATTERY. As previously stated, many people cry down a battery on their car with the mistaken idea that batteries are a hard proposition to keep m working order, that they "run down," etc., and do not, generally speaking, give satisfaction. We shall endeavor to prove the contrary. In the first place, we are most emphatic m remarking that "batteries" is 1 a subject not fully understood by anyone not having made a very exhaustive study of them. When we say understood we mean thoroughly understood, both from a constructional and operating standpoint, and this type of understanding is most necessary m order to be able to keep your battery m good "nick." The battery method of producing curent for various requirements is undoubtedly # the simplest, the chemical action m the plates of the battery generating electrical energy. . A primary battery has two "elements": (1) Positive, and (2) Negative. A secondary battery is the type commonly used, and is "charged" by.introducing electricity from an outside source, this current • being^ accumulated m the battery or as the American manufacturers have it — "stored." Its name is derived from the fact that it must receive its- current from another generating unit; it is, therefore, "secondary" to the other source of power. 1 CAPACITY POINTS. The average secondary battery may vary according to the work it is used for, from six to 12 volts. Generally, one will find a six- volt on the average car of light construction. Of course, a battery such as this is easily recharged for a nominal fee at a battery service station. The capacity of a. battery of tho latter type .is determined, of course, by tho .size, nature and number of plates used m each cell. In using a storage battery it- is essential that to exceed discharge rate, as by drawing current from the battery quicker than the rate intended will injure the plates, etc. The main attention needed to give the battery a "fair sp;n" is adding distilled water as the lattor becomes low m the cells through evaporation. Particularly is this necessary m the summer time, as the high temperatures induce quickeievaporation. It is a safe rule never to be .without a bottle of distilled water, especially if you are travelling m the country, as m 'country townr ships it is often impossible to obtain it, unless the town is large enough to warrant a chemist. This gentleman will generally be able to supply you, but the golden rule is; "Carry, your own, and don't forget to use it." One case we may cite of a man who has been running the same battery for a very long 1 period without recharging, and his method of treatment is worth while following. After returning home with. his. car he- disconnects ihlg battery, and at regular.

m simple terms, the "inner, •c, without .the guide of the ex-bwner-driver.

intervals fills up, with distilled water. To these two factors he attributes the efficiency of his storage battery. Of course, the disconnecting is not done if he is going out m another hour's time, but, if leaving it at the garage for a whole day or any longer period, disconnecting ' will pay. All chance of waste from "short circuit" or other reasons is eliminated. . TURN THE NUT. Novices need not be f eai-f ul 'of the disconnecting. The battery will be found m a most accessible place under the floor boards of the car, and turning a nut with a spanner is all that is needed to disconnect the "lead" from the terminal and place it away from any chance of contact. Another piece of very good advice is, if you. have occasion to take your battery to any person for re-charging or repairing, make sure that you are going to a reputable firm" who thoroughly understand the work, as .batteries are "a job on their own," and need specialised and expert attention when it comes to repairing or interior work of any sort". In the purchase of a car it is often noticed that magneto ignition ig a few pounds extra, the reason being that on many American cars battery ignition .is the "Standard," as the American driver claims that a battery gives a more "consistently steady flow of juice" than a magneto. . ' There is a lot m this argument, always providing the battery receives the regular and simple attention outlined above, and no worry need be felt m having a. battery ignition. It is a. most reliable method, especially with the modern type battery, and will often save you pounds on the purchase of your car. Le-t us now pass on for a brief while to the subject of brakes and braking systems. . • THE BRAKES. It is most essential that you should keep an eye on your brakes and all connected with them.- Here again is a most simple thing. The brakes are easy to understand, and, if a . careful study is made, easy to keep adjusted. A well-adjusted and efficient brake will one day mean the difference between life and death. . It is a very uncomfortable feeling to have when you realise that your .brakes are "not* as good as they might he." This talk should help to materially assist those m need of advice on this matter. Modern car brakes are attached to rear wheels, and m the case of "fourwheel brakes," oh both front and rear. Some cars are coming out fitted with a brake operated by the usual handlevor, and attached to a drum on the drive shaft of the engine. The latter style is very powerful, and has a tremendous grip, as the leverage is direct^ only a matter of a few inches separating the brake band from the handle of the brake lever. Possibly on hills these brakes might not prove quite so easy of use as the rear wheel type, as the latter can be applied more gradually, and steady the wheels down without absolutely gripping- them. In the case of the brake on the driving shaft the grip is just a little fierce until practice ■ has taught one the exact leverage to enforce interior and exterior brake bands.