FORD VAN POINTERS:
Page 30
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By R. T. Nicholson (Author of "The Book of the Ford ").
JUST LATELY,-at odd moments,. and, I am afraid, 'often at unwelcome moments,. I: have been thnging the Siamese National Anthem. Do you happen to know that particular effusion?
0 WAH..TAH NAH SIAM !
If you sing thatko.ver; (it goes..well enough to the tune of our own National Antheiii), I am sure your friends will appreciate it I I have been singing it lately,. because I have made a bad " bloomer " in these Pointers for February 21st.. I have slipped, tripped, and have been unmercifully. chipped. I have . nat.:only sung the Siamese National Anthem, but haveertiered..a brand-new suit of sackcloth and a chaldron of 'ashes :for due penance.
440.—The Candle-power .of the Tail-light.
I said, in the Pointers in question, that in fitting a tail-lamp in series with the headlights on the Ford truck, the tail-lamp might be of any desired candlepower within reason., irrespective of the candle-power of the headlights. That was sheer nonsense. I have only small excuse for making the statement, because I knew better all the time; however, as it happened,I had, been wiring up a tail-lamp from a battery, not in series, but in parallel, and in such circumstances the tail-light could, of course, be of any desired candle-power within reason, although its voltage must be that of the battery. I, therefore, want to correct my statement made in the issue for February 21st, and say that the voltage and candle-power of &I three lights, must be identical -when tail-lamp and headlights are run in series. It is generally best, perhaps always, to own up -when one is wrong. It is easy enough to blame the poor compositor, who too often plays the scapegoat's part, or to plead a headache, or a wedding, or grand:mother's funeral, or some kind of terrible crisis, as one's excuse. But I will not do it ; I will just sing that Siamese anthem once more !
My Kindly Critics.
quote the letters of two of my kindly critics on the matter at issue:— f` With reference to your article on Ford electric tail-lamp lighting in your Pointers in this week's issue of The Commercial Motor, as one who has received much useful information from this source, I hope you will pardon my calling your attention to what I think is an error and likely to cause some inconvenience to anyone carrying out your suggestions. The Point in question is this. "'' The voltage of all three bulbs must be the same.' Is this correct? Should not this be, Watts, or current consumption must be the same, or the total voltage of lamps included in the circuit must equal supply voltage ' ? . "'I find from practical application, if wired as per your diagram. thus :—
Fig. 286. -An incorrect wiring diagram in which the tail-lamp would burn brighter than Me headlights and would very quickly burn out.
3330 the 6 c.p. lamp, although the least candle, will burn the brightest, and this being the tail is not required; and-will. burn out very quickly. Of course, if gas' filled or so-called half-watt lamps are used for the headlamps, it would improve matters using vacuum lamp for tail. Is this what you interule.cli should he arranged ? I suggest .this arrangement :— "Headlight bulbs 6 volt 12 watt (2 amps.) gas-filled, each 24 c.p.
"Tail-light bulbs 4 volt 12 watt (2 amps.) carbon, c.p.
"I have allowed 3 watts per c.p. for carbon lamp. This would give far more lighting for the road and a strong filament with small candle-power at that.
"I trust you will excuse me calling your 'attention to this matter, not written in an authoritative spirit, but-by one who has received great help from your knowledge of the Ford car."
Thanks, " H.B.S." You write, not only as one who knows the subject well, but in the kindliest way.
" M.B." argues the matter in a different way, but to the same (right) effect:.
" To take a practical case. Total voltage from magneto 18 volts, two 6-volt '12 c.p. headlights, and one c.p. rear light in series, allow 0.5 watts per candle. 6 watts " Current in 12 c.p. bulbs = 6 watts = 6 volts .
= 6 ohms resist.
= 1 amp. 3. watts "Current in 6 c.p. bulbs = 3 watts -= .6 volts 0.5 amp. = 12 ohms resist.
" Total resistance in series = 24 ohms "Applied voltage = 18.
" Current in circuit = = 0.75 amps.
" . • . the 6 c.p. bulb will be 50 per cent. overrun, i.e., voltage applied to 6 e.p. bulb = 0.75 x 12 = -9 volts.
"Voltage applied to 12 cp. bulb 0.75 x 0 = 02 volts. the rear light will burn out and the head nect three bulbs of equal c.p. and voltage in series." lights dim, and . • . the only possible way is to con