View Full Version : Why I need change the reference value of an High Potential test depends if is AC/DC?
Mondaca
March 5, 2021, 09:50 PM
On a Vaccum interrupters, I need test the dielectric strenght with a High Potencial AC devices, manual of the vaccum bottles say that I need test them with 16kVAC, or, if I got a DC devices, I need test them with 23 kDC.
That’s right, because on this test I need check the leakage current on the peak of the sine wave, so, I got two options, inyect a RMS value of 16 kAC, or, multiplies this value per square of two, to get the peak of the sine wave and inject these value (23 kDC) with the high potential devices.
The question is: Why change the reference from AC to a DC test?, for example, if I test the vaccum bottles with 16 kAC I expect a leakage of current below to 1.3 miliamperes, but if I test the vaccum bottles with 23 kDC I need expect a leakage current below of 5 microamperes. Why change the reference value?
RabbleRabble
March 7, 2021, 11:52 AM
On a Vaccum interrupters, I need test the dielectric strenght with a High Potencial AC devices, manual of the vaccum bottles say that I need test them with 16kVAC, or, if I got a DC devices, I need test them with 23 kDC.
That’s right, because on this test I need check the leakage current on the peak of the sine wave, so, I got two options, inyect a RMS value of 16 kAC, or, multiplies this value per square of two, to get the peak of the sine wave and inject these value (23 kDC) with the high potential devices.
The question is: Why change the reference from AC to a DC test?, for example, if I test the vaccum bottles with 16 kAC I expect a leakage of current below to 1.3 miliamperes, but if I test the vaccum bottles with 23 kDC I need expect a leakage current below of 5 microamperes. Why change the reference value?
I believe it’s because when using AC there is capacitive leakage to consider.
rmr660
March 18, 2021, 08:55 PM
On a Vaccum interrupters, I need test the dielectric strenght with a High Potencial AC devices, manual of the vaccum bottles say that I need test them with 16kVAC, or, if I got a DC devices, I need test them with 23 kDC.
That’s right, because on this test I need check the leakage current on the peak of the sine wave, so, I got two options, inyect a RMS value of 16 kAC, or, multiplies this value per square of two, to get the peak of the sine wave and inject these value (23 kDC) with the high potential devices.
The question is: Why change the reference from AC to a DC test?, for example, if I test the vaccum bottles with 16 kAC I expect a leakage of current below to 1.3 miliamperes, but if I test the vaccum bottles with 23 kDC I need expect a leakage current below of 5 microamperes. Why change the reference value?
If I'm not mistaken it has to do with the current flow. In AC the current is going up and down (sinewave) as oppose to DC which current stays at the given amplitude. So with AC there is no "build up" so there isn't as much leakage that is acceptable when compared to DC.
RabbleRabble
July 3, 2021, 10:13 AM
If I'm not mistaken it has to do with the current flow. In AC the current is going up and down (sinewave) as oppose to DC which current stays at the given amplitude. So with AC there is no "build up" so there isn't as much leakage that is acceptable when compared to DC.
The AC valu is in milli Amps the DC is in micro Amps
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