The old farm house had been wrapped in insulation and sided.
However, the children found the soil spring-soft next to the building foundation, thanks to the Dean's fuel-bill contributions and the poor insulation of Bird Song.
Unless the insulation is perfect, the potential recorded falls short of that at the spot where the radium is placed or the water jet breaks.
The potentials that have to be dealt with are often hundreds and sometimes thousands of volts, and insulation troubles are more serious than is generally appreciated.
Each conductor has a resistance (at 60° F.) of 5.74 ohms per statute mile, and an average electrostatic capacity per mile between adjacent wires of o 06 microfarad, or between wire and earth of o I microfarad; the insulation resistance of each wire is about 5000 megohms per mile.
The one disadvantage of paper cables is the fact that any injury to the lead covering which allows moisture to penetrate causes telegraphic interruption to the whole of the enclosed wires, whereas if the wires are each individually coated with gutta-percha, the presence of moisture can only affect those wires whose covering is defective There is no reason for doubting, however, that, provided the lead covering remains intact, the paper insulation is imperishable; this is not the case with gutta-percha-covered wires.
The galvanometer being so adjusted that a current of definite strength through one of the coils gives a definite deflection of the needle, the amount of leakage expressed in terms of the insulation resistance of the wires is given by the formula.
The insulation is again tested, and if no fault is discovered the served core is passed through the sheathing machine, and the iron sheath and the outer covering are laid on.
In the types of cable that were first used, the wires, usually with a cotton insulation, were drawn into lead tubes, and the tubes filled with paraffin or other similar compound, which kept the wires from the injurious effects of any moisture which might penetrate the lead tube.
(4) Expansion or compression under the condition of heat-insulation, represented by curves called Adiabatics, such as BAZ or CDZ', which are necessarily steeper than the isothermals.
OHMMETER, an electrical instrument employed for measuring insulation-resistance or other high electrical resistances.
The Evershed and Vignoles form of the instrument is much used in testing the insulation resistance of electric wiring in houses.
One of these coils is in series with the armature circuit and with the insulation or high resistance to be measured.
Of the ends of the insulator and the current flowing through it, that is, by its insulation resistance.
In this case one terminal of the battery is connected to the earth, and the other terminal is connected through the galvanometer with the copper wire, the insulation of which it is desired to test.
In applying this method to test the insulation of indiarubber - covered or of insulated copper wire, before employing it for electrical purposes, I I I I_ it is usual to place B the coil of wire W (fig.
When the price of aluminium is less than double the price of copper aluminium is cheaper than copper per unit of electric current conveyed; but when insulation is necessary, the smaller size of the copper wire renders it more economical.
This insulation, however, is not sufficiently good for an electroscope intended for the detection of radio-activity; for this purpose .:..................... ?,:.?