Sparking takes place at the brushes when they are moved any considerable distance from the neutral position.
Or again, if a mercury surface be simply touched with a pin, the slight sparking that is produced on making the current will soon form a little pile of dirty oxide at the point of entry, and the contact will frequently fail.
It is claimed that sparking is by this method almost entirely avoided.
The "short" can usually be found by an occasional sparking or smoke at the point of trouble.
Brushes sparking badly on commutator of dynamo--due to poor contact.
And that current, sparking over the interstices between the aluminium lattice-work and envelope of a Zeppelin, must certainly ignite the inflammable gas with which the ballonets are filled and which is so constantly escaping.
Therefore, as we had carried out an alteration of the apparatus and intended to try sparking upon the pole again after dark, I rang Roseye up on the telephone shortly after five o'clock.
Mine, however, were unusually fierce, especially when both were working, one for the propeller, and the other either for the searchlight or the directive sparking apparatus.
One was, perhaps, gazing through his glasses at the pole and, seeing in the darkness the sparking over the insulators set in the steel guys, ejaculated the natural expression of surprise that I overheard.
Surely there could not be anybody else watching thesparking upon the pole!
Neither commutator nor slip rings are required, and all sparkingis avoided.
The petroleum above the mercury prevents sparking between the platinum wire and the mercury when the latter falls below anyone of them.
As they expected, the sparkingplugs were completely clogged.
The sparkingbeing still weak, he examined the magneto: it was choked with grease.
But the interruption of the sparking was only temporary, and he reached the island of Celebes safely.
While he was searching for a convenient landing place the sparking ceased altogether.
The engine missed sparking once or twice when he was half-way across the Straits, and he shouted to Rodier to loose the life buoys in case it failed.
Hoping that the failure in the sparking was only temporary, Smith swung the aeroplane round, in order to take advantage of this calm region of air and at least fly in the right direction.
According to the report of the Committee on Standardization of the American Institute of Electrical Engineers, the sparking distances in air between opposed sharp needle points for various effective sinusoidal voltages are as follows (vol.
This governor also shifts the position of the brushes on the commutator to prevent sparking as the current flowing through the magnet coils is changed.
The sparking distance through air between needle points, which is greater than that between smooth surfaces, is 5.
In dynamos of several hundred or more kilowatts capacity the pressure of continuous current has not thus far been pushed above 4,000 volts, because of the danger of sparking and flashing at the commutator.
At its lower edge each insulator has a diameter of nine inches, and a small glass sleeve extends several inches below this edge and close to the wooden pin, to prevent sparking from the lower wet edge of the insulator to the pin.
It may be noted at once from this table that the sparking distance between the needle points increases much faster than the voltage between them.
Thus there is never a complete open circuit and sparking is prevented.
When the sparks are long the term blp is the most important and the sparking potential is proportional to the spark length.
In any case thesparking should now be continued, the pump being at rest, and the variations of tube resistance watched by adjusting the spark gap.
When the spark would rather go over an inch of air in the spark gap than through the tube the pumping andsparking may be interrupted and the tube allowed to rest for, say, five minutes.
Exchange his sheep for shells, or wool for a sparking pebble or a diamond.
It is thought by some that horses have no intelligence, but a team that knows enough to take in a sporadic case of buggy sparking has got sense.
Nine-tenths of the sparking is done by boys who haven't got their growth, and they look so green that it is laughable for old folks to look at them.
A green boy, without a dollar, present or prospective, sparking a girl regularly and talking of marrying is a spectacle for gods and men.
If there was a law against young galoots sparking and marrying before they have all their teeth cut, we suppose the little cusses would evade it some way, but there ought to be a sentiment against it.
If the sparking did not take place until the crank had actually passed the dead center, the full effect of the compression and subsequent explosion pressure would not be had.
The throttle may also be a most effective means of economizing fuel when the engine has a first class sparking device, as in that case the throttle can be closed down to provide a very small opening.
The fine wire wrapping represents the secondary coil, which is raised to a high voltage, and this actuates the sparking mechanism.
Two sparking points, each insulated one from the other and from the burner, are arranged at each burner, so that a spark between the points passes through the jet of gas and ignites it.
The "Exide" sparking battery is also adapted for electric lighting of automobiles, for head lights, tail lights, side and interior lights.
This helps to eliminate the sparkingat the contacts.
Two storage batteries are used, one being charged while the other is operating the sparking coil.
A number of sparkingpoints and the secondary of an induction coil are connected in series.
G represents the leads to the sparking coil terminals.
Phantom view of an "Exide" sparkingor ignition battery.
Portion of oscillograph record taken with a cinematograph film camera =showing the effect of switching off a high pressure feeder= and illustrating the violent fluctuations produced by sparking at the switch contacts.
There is, consequently, little or no tendency for sparking to occur at the brushes, and they therefore need not be shifted on this account for different loads.
Found two sparking plugs cracked and the magneto very weak.
Sava and I stopped and tinkered at the old machine for about an hour, changed all the sparking plugs again, after which she went better.
No difference was detected between the sparking distances at the two ends of the cable, nor was any rise of pressure observed when the cables were joined direct on the dynamo.
The wires leading to the primary coils of the sparking coils pass through the explosive a meter or more apart.
A series of competitive tests of enclosed motors for use in mines has been announced, and is in progress, the object being to determine whether or not sparking from such motors will cause an explosion in the presence of inflammable gas.
Plate VII, comprises two sparking induction coils and a rapidly revolving metallic drum driven by a small motor, the periphery of the drum having a thin coating of lampblack.
In this position sparking at G produced strong sparking in the detector, although the distance was such that no sparking was produced without the reflectors.
This is characteristic of all electric waves, as no single sparking apparatus will produce anything but waves parallel to the spark gap.
Hertz produced these conditions by setting up his coil and sparking knobs at some distance from a reflecting wall, Fig.
The sudden parting of H and S would produce strong sparking across the gap between them if it were not for the condenser, which consists of a number of tinfoil sheets separated by layers of paraffined paper.
High-pressure direct current is not easily generated, since the sparking at the collecting brushes as they pass over the commutator segments gives trouble.
