How to Find an Earth Fault on Board Ships? Essay

world transmutation is considered very critical on board a ship. Some ships which tend at 440 V do not have any trip devices accustomed for a single existence fault. However when the operating voltage exceeds 3000V, it is mandatory to have a shield system which isolates when a machinery suffers an humankind fault. How to find out an Earth Fault?The seriousness of the carry out to be taken on an Earth Fault depends on the part of the electrical system it affects. Conventional ships which operate on 3 Phase, 440V, have earth fault indicators installed on all three phases. Any earth fault on a 440V system is considered to be a serious trouble and immediate action is required to identify the faulty unit of ammunitionabout. Any earth fault on 220V or any low-spirited voltage illumine circuit can be considered as important but need not require immediate attention. However, attention should be paid at the next earliest opportunity. determination Earth Fault on 440V circuitWhenev er there is an earth fault alarm, immediately inform to electrical military officer (if he is on board). First action is to check the loyalty of the alarm. Usually there will be a test button which when pressed, resets the alarm and rechecks the condition of the earth fault. If the ship is having IAS (Integrated Automation System), check on the computer in the list of events after which the alarm has activated. If IAS facility is not available, there is only iodine option of isolating each and every machinery in the 440 V circuit and check whether the earth fault indication returns back to normal.Isolation of all machinery, which operates on 440V, is not always possible. Certain critical equipment resembling steering gear and lubricating oil pumps cannot be isolated for when the ship is underway. However changeover can be do from running machinery to the standby one and thus the earth fault can be found.Finding Earth Fault on 220V CircuitFinding an Earth Fault on a 220V circuit is comparatively difficult than a 440V circuit. The main reason being the lighting circuits found all round the vessel. However, any earth fault alarm with respect to a 220V circuit is usually treated as important but not an emergency. When a 220V earth fault alarm sounds, as said earlier, the trueness of the alarm is checked by pressing the test button and consequently investigation can be fathered on each and every 220V circuit.Example Earth Fault alarm sounds on a 220V table1. Check the trueness of the alarm. 2. Isolate the complete Group start panel for a lighting cleavage one by one. 3. Check the Earth Fault indicator for status (still faulty or normal). 4. If faulty, then put on the breaker which is put off earlier and isolate other group start panel for lighting circuit. 5. Once the group start panel is identified, then individual lighting switches argon saturnine off one by one and checked for the alarm condition. 6. When any switch when turned off and thus the condit ion becomes normal, then this lighting circuit is marked and then inspection is done on the event light for abnormalities.Ingress of moisture is most common reason for an earth fault. assemble Idea Instead of turning off breakers one by one for the lighting circuit, I followed a method where I turned off all lighting circuit of a crabby doubted area. This method helps usually when there are two or more earth faults in 220V lighting circuit. By turning off all the breakers of a particular area, then switching on the breaker one by one will eliminate multiple earth faults. When I turned off lighting switches one by one, it was difficult for me to identify multiple earth faults. Once the particular faulty circuit is spotted, then we have to further break them into individual dividable pieces and check them for earth faults. For this as usual, we use megger against earth. By removing fuse of the two phase lines, each line can be tested and the fault pinned down