TESTING ELECTRICAL EQUIPMENT
TESTING ELECTRICAL EQUIPMENT BRITISH RACING DRIVERS’ CLUB VISITS THE LUCAS FACTORY AT BIRMINGHAM
ELI.criacAL equipment plays a big part in the working of any car. Even on a racing-car, with no lamps, dynamo, self-starter, screen-wiper, or horn, there is still the vital ignition apparatus, and sometimes an electric petrol pump as well. In sports-car races, particular]) of the type of the Le Mans 24-hour event, almost every item of the equipment listed above is needed, and becomes as important as the power of the engine itself. Last month a party of members of the British Racing Drivers’ Club visited the Lucas works at Birmingham, with George Eyston as the guest of honour. Eyston had had recent experience of Lucas products in his long-distance records in America, and was able to tell Oliver Lucas, who received the party, that the bigheadlamps on his ” Speed of the Wind” gave ample driving light even at speeds of 170 m.p.h. ! He had used the self-same pair of headlamps on another car in a previous attempt on the 24-hour record. On that occasion the frame broke, and in consequence the lamps had received a tremendous battering and vibration. However, he was able to fit them to ” Speed of the Wind ” without any overhaul,
In the morning the B.R.D.C. party split into two groups, one visiting the battery works and the other the Service Station. Later they were conducted all over the main works, which has a floor area of a million square feet, and the only regret was that so little time was available to see the many intricate processes of manufacture and testing. A feature of much interest was the Refrigerator ROOM. Fortunately, this was not as cold as it might have been, for one of the tests is to leave a car (without water in the radiator 1) in this chamber for sixteen hours with the tem
perature at 47 degrees of frost. The starter must then turn the engine over at a reasonable r.p.m., enough to secure a start. Carburetter settingsare also tested in this cold temperature, to enable the various manufacturers and the electrical suppliers to work together.
In another room opposite temperatures could be attained, to reproduce conditions at will, with steam4aden air to give the requisite dampness. Those who have experienced a sheared
The Monte Carlo Rally A Product of Auto-Union -The • . • D.K.W. •• • 17 A Lively M.C.C. Meeting Achievement and Tragedy … • • • 51 Letters front Readers 53 A )1 old Master Re-discovered 57
Club News … 5!1 On the Road with a Leyland Eight 63 On the Trend of Design • • • 65′ Rumblings … • • • 69 Eyston’s Own Story… • • • • • • 71
Midget Racing in the U.S.A. 72 Continental Notes and News 73 Fingle makes its ” Marque 76
shaft were interested in a machine, designed for testing spindles of various kinds, which applied a twisting force of 10′ seventy-two times a second to a constantly rotating spindle.
Automatic advance and retard mechanisms are tested by a kind of miniature brake, which records the horsepower given off by an engine according to the varying position of the spark. One of the most interesting features of all was the Gauge Room, where all the gauges used in manufacture are checked with meticulous accuracy. A Zeiss Contour Projector throws an image, greatly magnified, on a horizontal screen. Small parts can thus be seen on a drawingboard with a profile from 10 to 100 times
full size. Even a hair would look like a mighty cable. Then there is an automatic gauging machine, which selects the pivot pin inserts in the contact breaker plate, but discards all that are oversize or undersize
by more than .0015 in. 7,200 pins an hour pass through this machine.
Condensers are tested by means of a 750 volt D.C. supply through contact breakers operating approximately 4,000 times per minute. The charge is measured on a moving coil ammeter, but a thermal ammeter is used for measuring the discharge, owing to its extreme rapidity. Charge and discharge readings should be equal, a low discharge indicating a leaking condenser.
The high frequency test for armatures is to induce current from a 1,000 cycle A.C. field. At every 11 revolutions of the rotating armature a white light shows on an instrument panel, ensuring that the tester covers the whole of the armature. If there is a short circuit, a blue light goes up, while a red light indicates earths, and is supplied from a 500 volt transformer. There is also a neon light, which is extinguished if any part of the .apparatus is not working properly. Magnetos were seen sparking at 10,000 r.p.m., and also at the opposite extreme
of 60 r.p.m. The windings are first tested separately. The primary. winding is supplied at 8 volts D.C. through a contact breaker operating at 5,000 times a Minute, and the resulting secondary voltage is fed to a three-point spark gap. Wm earth prod is used to test the insulation, ‘attracting a spark through any faulty part. Continuity of windings is tested by passing a 2-volt current through primary and secondary windings. The very
low voltage supply shows up any tiny break, as the spark cannot jump across. TO adjust the notes of horns by car would be a noisy procedure, and one lacking in accuracy, and there is an ingenious machine to test the frequency with, apparently, a number of concentric
circles all rotating on a dial. When a horn is switched on, a number of the circles begin to rotate in the opposite direction, but between the two sets there is one circle which appears stationary. This gives the frequency of the note, and enables the horn to be tuned in to the frequency of other horns. The construction of the fog-lamp or
pass-light was also demonstrated. A lamp was fixed opposite a screen, and first the effect of the lower half of the reflector was shown, giving the basis of the flattopped beam. When the upper half was brought into use, the beam was still quite Hat-topped, but the light was doubled, though it was all concentrated below the axis of the reflector. With the fluted glass front in place, the beam became broader—it is designed to show up both sides of the road without causing dazzle or upward rays. Many other processes were seen, often too intricate to be understood at a passing glance, but enough has been said to show some of the careful methods of test and
counter-test which have built up the Lucas reputation.