The Standard Electrical Dictionary Part 4

Inverted commas, -..-.

THE AMERICAN ALPHABET.

A .- L ----(Continuous) W .-- B -... M -- X .-..

C ..s. N -. Y ..s..

D -.. O .s. Z ?.

E . P .....

F .-. Q ..-. Ch ---- G --. R .s.. ? .-.- H .... S ... ? ---.

I .. T - ? ..-- J - . - . U ..- ? ..-..

K -.- V ...- ? --.--

NUMERALS 1 .--. 4 ....- 8 -....

2 ..-.. 5 --- 9 -..- 3 ...-. 6 ... ... 0 -----(Continuous) 7 --..

[Transcriber's Note: The "s" in the American Code indicates a "s.p.a.ce". I leave the following to the reader's imagination. See the original image.]

Comma (,) Semicolon (;) Colon (:) Colon Dash (:~) Period (.) Interrogation (?) Exclamation (!) Dash (-) Hyphen (-) Pound Sterling (?) s.h.i.+lling Mark ( )

[Image of page 21: THE AMERICAN ALPHABET.]

22 STANDARD ELECTRICAL DICTIONARY.

[Transcriber's Note: I leave these to the reader's imagination. See the following original image.]

Dollars ($) Decimal Point (.) Cents (c) Paragraph () Pence (d.) Fractional Mark (--) Capitalized Letter Italics or Underline Colon followed by Quotation :"

Parenthesis ( ) Brackets [ ]

Quotation Marks " "

Quotation within a Quotation " ' ' "

[Image of page 22: THE AMERICAN ALPHABET.]

The princ.i.p.al differences in the two codes are the use of s.p.a.ces in the American code, such being excluded from the International code. This affects the letters C, R, Y, & Z.

The following diagram, due to Commandant Perian, enables the letter corresponding to an International code sign to be rapidly found with the exception of R.

<- dot="" start="" dash="" -=""> / E T / / I A N M / / / / S U R W D K G O / / / / / / / / H V F U L A P J B X C Y Z Q ? CH

Fig. 10. Diagram for translating the Morse Alphabet.

In order to find what letter corresponds to a given sign, starting from the top of the diagram, each line is traced down to a bifurcation, taking the right hand line of each bifurcation for a dash, and the left hand line for a dot, and stopping when the dots and dashes are used up.

Thus, for example,

the signal -.- - leads us to the letter d,

the signal - - - - to the letter j and so on.

23 STANDARD ELECTRICAL DICTIONARY.

Alternating. adj.

Term descriptive of a current changing periodically in direction. (See Current, Alternating.)

Synonyms--Oscillatory--periodic--undulatory--harmonic.

Alternating Current Arc.

The arc produced by the alternating current. It presents several peculiarities. With an insufficient number of alternations per second it goes out. As the carbons wear away equally it is adopted for such lamps as the Jablochkoff candle, (see Candle, Jablochkoff). As no crater is formed the light is disseminated equally both up and down. For this reason to get full downward illumination a reflector is recommended.

Alternating Current System.

A system of electric distribution employing the alternating current. For transmission in the open air or in conduits a high potential circuit is used, from 1,000 to 10,000 volts being maintained at the central station. Two leads unconnected at the end lead from the station. Where current is desired a converter or transformer (see Converter) is placed, whose primary is connected to the two leads bridging the interval between them. From the secondary the house leads are taken with an initial potential in some cases of 50 volts. The converters are thus all placed in parallel. By law or insurance rules the converters are generally kept outside of buildings. Where no secondary current is taken from the converters very little primary current pa.s.ses them on account of their counter-electromotive force. As more secondary current is taken the primary increases and this accommodation of one to the other is one of the interesting and valuable features. Street lamps are sometimes connected in series. Each lamp in such case is in parallel with a small coil with iron core. While the lamp is intact little current pa.s.ses through the coil. If the lamp is broken, then the converter impedes the current by its spurious resistance, q. v., just enough to represent and replace the resistance of the extinguished and broken lamp filament.

(See Meter, Alternating Current; Motor, Alternating Current.)

Alternation.

The change in direction of a current. The number of such changes is expressed as number of alternations; thus a current may have a frequency of 500 or 20,000 alternations per second.

[Transcriber's note: One alternation per second is now called one hertz.]

Alternation, Complete.

A double alternation; a change from one direction to the other and back again to the original phase. A symbol derived from its graphic representation by a sine curve is used to indicate it. The symbol is ~

24 STANDARD ELECTRICAL DICTIONARY.

Alternative Path.

A second path for a current appearing as a disruptive discharge. Where two paths are offered the discharge, as it is of alternating or oscillatory type, selects the path of least self-induction. Thus a thick bar of copper, with no air gap, may be abandoned by the current in favor of a small iron wire with an air gap, but which has less self-induction.

The lightning arresters, q. v., for the protection of telegraph offices are sometimes based on these principles. A path of very high resistance but of small self-induction is offered between the line and the earth.

This the lightning discharge selects in preference to the instruments with their iron cores, as the latter are of very high self-induction.

Alternator.

A dynamo electric generator supplying an alternating current. (See Dynamo, Alternating Current.)

Synonym--Alternating current generator or dynamo.

Alternator, Constant Current.

An alternating current dynamo supplying a current of unvarying virtual amperage. Alternators of this type are constructed with an armature of high self-induction. Sometimes fine winding contained in deep peripheral notches in the core-discs is employed to magnify the self-induction.

Such generators are employed for series lighting, especially arc-lighting.