Arrester Separators] Dust Between Carbons:--Discharges between the carbon blocks tend to throw off particles of carbon from them.
Assume, as a third case, that the contact at the point X either is with a low foreign potential or is so poor a contact that the difference of potential across the gap of the carbon arrester is lower than its arcing point.
Cook Air-Gap Arrester] A form of Western Electric arrester particularly adapted for outside use on railway lines is shown with its cover in Fig.
The central-office carbon arrester will operate, grounding the line and increasing the amount of current flowing.
It is obvious, therefore, that a fuse must be located between the carbon arrester and any part of the line which is subject to contact with a potential which can give an abnormal current when the carbon arrester acts.
Roberts "Self-Cleaning" Arrester] The Roberts carbon arrester is designed with particular reference to the disposal of carbon dust and is termed self-cleaning for that reason.
A patent water spark arrester is used which is an absolute protection.
Coal sparks are heavy and have little life, and with some engines no spark arrester is needed.
But talking of radio reminds me that we ought to get busy with that lightning arrester we were talking about.
The dust-arrester needs its contents renewing once in one, two, or three years, according to the make of gas.
Later investigations have proved that it exercises a yet more important influence as an arrester of metamorphosis.
Consider then, first, the representation of the Servant of the Lord as the arrester of incipient ruin.
This done connect one of the end binding posts of the tuning coil with the ground wire and a post of one of the contact slides with the lightning arrester or switch which leads to the aerial wire.
Connect a length of wire to the top post of the arrester or just above it to the wire, run this through the leading-in insulator and connect it to the slider of your tuning coil.
Screw the end of a piece of heavy copper wire to the lower post of the arrester and run it to the ground, on porcelain knobs if necessary, and solder it to an iron rod or pipe which you have driven into the earth.
If you want to use a lightning switch instead of the air-gap arrester then fasten it to the outside wall instead of the latter and screw the free end of the leading-in wire from the aerial to the middle post of it as shown at C in Fig.
Section CD of the rod is used therefore simply to shunt the inductance of winding H to high frequency lightning discharges, leaving the lightning discharge path in the arrester a non-inductive highly efficient path.
The series resistance prevents a heavy short circuit through the arrester and limits the current to a value that is readily broken by the cut out and is not enough to impede the passage of the discharge.
For what kind of service is the form of arrester just described used?
Carbon lightning arrester with fuses as used on telephone lines.
The construction of this arrester is based on the well known principle that lightning discharges more readily at points or angles than elsewhere.
If there be no lightning arrester the choke coil evidently cannot perform this function.
In this connection the primary objects of the choke coil should be: 1, to hold back the lightning disturbance from the transformer or generator until the lightning arrester discharges to earth.
While the deflecting cone was regarded highly as a spark arrester and used practically to the exclusion of any other arrangement, it had the basic defect of keeping the smoke low and close to the train.
If you use a loop antenna, of course, no arrester is needed.
To protect the house and your apparatus from lightning insert a fuse and a little carbon block lightning arrester such as are used by the telephone company in their installations of house phones.
The arrester is designed to have two legs between line and line.
The amount of energy to be dissipated in the arrester depends upon the kilowatt capacity of the generator, the internal resistance of the cells, and the time required to operate the circuit breakers.
Oscillograph record of the phenomena that take place in the different circuits or selective paths of a multi-gap arrester during a discharge such as shown in fig.
For mixed overhead and cable systems the choice of arrester will be a matter of judgment.
It is important to avoid the mistake of choosing an arrester for a thoroughly grounded neutral when the neutral is only partially grounded, that is, grounded through an appreciable resistance.
On three pole circuits,~ two arrester units are used, with the same connections as for four pole circuits, except that there are but three line connections instead of four as in fig.
It has been customary to ground a lightning arrester by means of a large metal plate buried in a bed of charcoal at a depth of six or eight feet in the earth.
Westinghouse three pole or four pole arrester in weather proof wooden case which protects the arrester units from rain and snow when they are installed in exposed locations, as on poles or buildings.
The difference in design lies in the use of a fourth arresterleg between the multiplex connection and ground or ungrounded system.
The system of trays is connected between the line and ground, and between line and line, a horn gap being inserted in the arrester circuit which prevents the arrester being subjected to the line voltage except when in action.
With sufficient series resistance to prevent loss of synchronism, the arrester failed to protect the system under severe conditions.
Four choke-coils were connected in series with each line wire, and between these choke-coils three lightning arresters were connected, while a fourth arrester was connected to the line before it reached any of the choke-coils.
So, too, an increase of inductance in a circuit adds to the work of an arrester in breaking an arc.
The increase of resistance in series with a lightning arresteras well as the increase in the aggregate length of its air-gaps subjects the insulation of connected apparatus to greater strains at times of lightning discharge.
When a lightning discharge takes place through an arrester the resistance which the arrester offers to a flow of current is for the moment greatly reduced by the arcs which the lightning sets up in jumping the air-gaps of the arrester.
This form of arrester may be connected directly from line to earth without the intervention of any outside resistance, since the carbon rods may easily be given all the resistance that is desirable.
This coil is connected in series with the line wire between the point where the tap for the lightning arrester is made and the station apparatus.
If this connection is poor it may render the arrester useless so far as protection from lightning is concerned.
After long use and many discharges an arrester of the class here considered gradually loses its power to destroy electric arcs.
In one make of lightning arrester the row of little brass cylinders is connected at the ends to carbon rods which form a resistance for the purpose just mentioned.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "arrester" in a variety of sentences. We hope that you will now be able to make sentences using this word.
