ELECTRICAL FAULTS

Evening Post, Volume CIX, Issue 132, 7 June 1930, Page 26

ELECTRICAL FAULTS

DAMAGE TO INSULATION Electrical faults in motor-cars are not frequent nowadays, but when they do occur they are primarily due to vibration. Wires which hang looso or sag will, under the vibration of the ear, rub against metal parts of the engine or chassis. This movement and consequent friction will wear the insulation, and a short circuit in the current will result. Very often this "short" is intermittent. When tested with the car at rest, there may be no leakage. But when the car gets on the road the "short" is continually being set up. This is often the cause of a discharged battery. The current, perhaps in the wire from the battery to the starter switch or the lamp circuit switch, "shorts" intermittently. If it is in the lamp circuit it may be discovered by flickering of the lamps when the car is running, while they burn steadily when the vehicle is at rest. Such a condition very often denotes a loose wire, which, by vibration, comes in contact with some part of the frame, becomes chafed, and allows a short circuit to occur.

The remedy for these troubles lies in a proper support of the wires and proper insulation. Much of the trouble arises at places -where the wires are led through holes in. the frame or mudguards. A; very'; usual place is in the : valance between the car frame and the running-board when the battery is carried on the latter. The valance is thin metal, and the, hole through which the cable passes has sharp edges. These will in time cut the cable and causo trouble. This "short" may be intermittent. It may be continuous. It may not be a real short in dry weather, but it may become one in wet. It can set up all kinds of puzzling troubles with the lighting and starting installation, and has been known to result in what might almost be called a "trickle" discharge from the battery, soon running it down.

A fabric body should not be neglected for long. If left, dirt will become ingrained into the material and prasent a dull appearance, even after hosing. Very dirty fabric can be cleaned by washing down with just warm water and soft soap. Polishing is effected by the use of a suitable • preparation, of which there are many on the market purchasable in suitable colours, according to the colour of the fabric. Occasional cleans during the week may be effected by brushing off the dirt and then polishing.

If the starter pinion of a, car jams frequently the probability is that the shaft is bent. Jamming of the starter pinion is generally due to starting with the ignition advanced. Always retard the ignition when about to press the starter pedal. Similarly, a great proportion of back-fires in using the crank to start the engine are due to advanced ignition. Have the ignition fully retarded on such occasions. '

The fire-fighting staff of the Ontario Department of Lands and Forests is equipped with 55 motor-cars, 115 motortrucks, 106 motor-boats, 53 railway mo-tor-ears,' and 26 aeroplanes, as well as other important apparatus.

Car owners seldom thinK of sparking plug leads when the, ignition system seems'to .be functioning efficiently. Yet it should be remembered that the- conditions under which the leads work involve high temperatures and escaping oil which affects the rubber. Cracks iii the insulation permit the cumnt to escape before it reaches the cylinder or, at least, to diminish in intensity. The charges fires, but weakly.