T
treez
Guest
Hello,
The following 3kw electric car charger is totally encased in a metal enclosure which is connected to earth ground, -I assume multiple parts of the internal PCB are electrically connected at various points to this earthed enclosure. The reason for earthing is safety , but also , it is good for EMI noise reduction. This is because the noise radiated out of the switching power supply components, has an affinity to couple to earth, and as such, it readily couples to the earthed enclosure (instead of coupling to earth outside the enclosure and causing interference). Then, when the noise has coupled into the earthed enclosure, it runs along it, eventually finding a Y capacitor, through which it flows, before going back down the neutral wire, and in the process, getting attenuated by the differential mode filter.
It doesn’t run down the earth connection wire because the common mode choke makes that a high impedance path to the noise.
So anyway, we see how essential an earth connection is for EMI noise reduction. So how do European plugs manage to avoid this noise problem?, they have no earth connection. The power supply would not be earthed and the noise will run wild.?
EV charger ;3kw
https://www.google.co.uk/url?sa=t&r...-mu3UYfLLlcKKhARQ&sig2=97vBkIqtM4HfatAm9Dxkcw
The following 3kw electric car charger is totally encased in a metal enclosure which is connected to earth ground, -I assume multiple parts of the internal PCB are electrically connected at various points to this earthed enclosure. The reason for earthing is safety , but also , it is good for EMI noise reduction. This is because the noise radiated out of the switching power supply components, has an affinity to couple to earth, and as such, it readily couples to the earthed enclosure (instead of coupling to earth outside the enclosure and causing interference). Then, when the noise has coupled into the earthed enclosure, it runs along it, eventually finding a Y capacitor, through which it flows, before going back down the neutral wire, and in the process, getting attenuated by the differential mode filter.
It doesn’t run down the earth connection wire because the common mode choke makes that a high impedance path to the noise.
So anyway, we see how essential an earth connection is for EMI noise reduction. So how do European plugs manage to avoid this noise problem?, they have no earth connection. The power supply would not be earthed and the noise will run wild.?
EV charger ;3kw
https://www.google.co.uk/url?sa=t&r...-mu3UYfLLlcKKhARQ&sig2=97vBkIqtM4HfatAm9Dxkcw