: When leakage electric current is originated from electric apparatus in water, the electric field will be produced in the water, bringing about possible fatal accidents of workers engaging in underwater jobs.
The electric shock hazard in water corresponds closely with the electric field intensity, the stronger its intensity is, the bigger its hazard becomes. Therefore, investigation in this field is required to prevent such underwater electric shocks to workers.
In this report, study was carried out of the electric field intensity with reference to leakage electrode, and the fundamental data on the electric field intensity have been obtained in terms of various electrical and geometrical factors of leakage electrode.
Factors concerning the electric potential of leakage electrode are those of electric potential of power source (V0), resistance of feeder (Rc), resistance between leakage electrodes in water (Rw), etc. Those concerning the geometrical character of leakage electrode, size of electrode (a), sharpness of figure of electrode (m), distance between leakage electrodes (d), etc.
Several models simulating electric field given below were made, and the influence of the above factors on the electric field intensity by the use of these models has been studied analytically, giving a numerical example.
--- Condition of the electric field :
The frequency of leakage current was less than 60 Hz.
The leakage current was caused between two feeders, or between one feeder and a common pole such as a body of ship.
The potential drop on the surface of leakage electrode neglected.
The main result of the study are as follows :
1. In respect of electric factors ;
By increasing (V0) and (Rw) and decreasing (Rc), the maximum intensity of the electric field will be increased.
2. In respect of geometric factors ;
Both by increasing (d) in case that leakage electrodes have the same polarity as well as (m) and by decreasing (d) in case that leakage electrodes have the different polarity each other as well as (a), the maximum intensity of the electric field will be increased.
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