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With two conductors that are supposed to be insulated, the amount of insulation can vary depending on the thickness of the insulating material, the amount of moisture, or from being contaminated with an electrically conductive substance. The insulation could be thin in one or more spots due to improper manufacture, or due to overheating, or due to applying excessive mechanical force, etc. So, megging the insulation is intended to check for any of these imperfections.
When the voltage is applied across two conductors that are supposed to be insulated, the megohmmeter measures the current that flows. If the current is lesss than the specified amount, then the insulation is meeting the specified minimum. If it fails the test, then there is a problem such as I mentioned above.
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What are the type of pre commissioning testings done before commissioning a electrical substation of voltage rating 110 kilovolt?
Depending on the equipment required for the substation,some of the tests are as follows: meggering,hi-pot testing,continuity checks,c.t. testing,relay testing,ngr testing, capacitance bridge test's on transformers.
Where can you get on line IEEE standard for 600 volts cable testing?
You can try the IEEE website, but for any good, useful info from them, you have to be a member. Have you tried the NEC (book, or online) for info on 600V cable testing? I would think that a basic "Meggering", and/or "High-Pot" testing of the cable would suffice.
How much volt apply to instrument cable meggering?
500v
Why is AC meggering not used?
You do not use AC to megger a device, because the purpose of meggering is to measure the insulation resistance of the device. You use DC to do that. If you used AC, you would be unable to differentiate between insulation leakage and capacitance.
Why MICC cables are meggering?
since the MICC cable the isolation between core is less as well as the outer sheath has probability of getting damaged during installation so meggering is important Any clarification mail to amal_elias@ymail.com
What does it mean by meggering?
On the whole megger testing is non destructive. What happens is a DC voltage is applied to the device or winding under test. It is an insulation test to see is the insulation has been injured in any way to cause a short circuit when normal power is applied to it. On my megger there are 3 ranges 300V, 750V, and 1000 volts. Applying the proper voltage is essential to not damaging the device you are testing. Working voltages up to 240 volts should use the 300 range. Working voltages up to 600 volts use the 750 volt range and working voltages above 600 use the 1000 volt range. As you can see if you used the 1000 volt range on a device that had a working voltage of say 24 volts you could damage the insulation just by testing it. So meggering a device is non destructive if you use the tester as its instructions tell you to.
When using a megger at 1000v and your reading is 2700 megohms is it a problem?
What is the acepable rating on a #3 wire when meggering @1000v
Can you use ac supply for cable meggering?
No. The cable has capacitance, and an AC source would not be able to distinguish between capacitance and leakage.
How meggering is done?
Megger testOn the whole megger testing is non destructive. What happens is a DC voltage is applied to the device or winding under test. It is an insulation test to see is the insulation has been injured in any way to cause a short circuit when normal power is applied to it. On my megger there are 3 ranges 300V, 750V, and 1000 volts. Applying the proper voltage is essential to not damaging the device you are testing. Working voltages up to 240 volts should use the 300 range. Working voltages up to 600 volts use the 750 volt range and working voltages above 600 use the 1000 volt range. As you can see if you used the 1000 volt range on a device that had a working voltage of say 24 volts you could damage the insulation just by testing it. So meggering a device is non destructive if you use the tester as its instructions tell you to.
Why ac megger not use in cable meggering?
Because the cable has capacitance, and an AC source would not be able to distinguish between capacitance and leakage.
What is the preferred order for performing testing on information technology project?
1. unit testing,integration testing, system testing, user acceptance testing. 2. unit testing, system testing , integration testing,user acceptance testing. 3. unit testing, system testing , user acceptance testing,integration testing. 4. unit testing, ,integration testing, user acceptance testing,system testing.
What comes after unit testing?
These are the next testing levels after unit testing: 1 Integration testing 2 Component interface testing 3 System testing 4 Operational Acceptance testing
