EMI - Electromagnetic Interference

I was reading through document, it mentioned that the EMI radiated from a 750kVA transformer is 40mG at 15m. What exactly does that mean? is the Interface mentioned radiated at 50/60Hz. What about EMI at other frequencies. I'd imagine that they would be limited to harmonic frequencies only, which will quite minimal, is that right? Any Comments?

The reason I ask is because electronic equipment can be susceptible to EMI interference, I had been given a data sheet for an IT unit, where it mentioned the equipment will be not be susceptible to EMI provided that EMI does not exceed the following:-

150mG @ 50Hz

150mG @ 100Hz

150mG @ 500Hz

75mG @ 1KHz

75mG @ 5KHz

75mG @ 10KHz

75mG @ 20KHz

75mG @ 30KHz

75mG @ 40KHz

75mG @ 50KHz


Cheers.

fzn10 said:

I was reading through document, it mentioned that the EMI radiated from a 750kVA transformer is 40mG at 15m. What exactly does that mean?

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It means that 15 meters away, the maximum magnetic field strength emitted by the transformer would be 40 milligauss. The magnetic field will get stronger the closer you are to the transformer. Gauss is a measure of magnetic field strength.

is the Interface mentioned radiated at 50/60Hz. What about EMI at other frequencies. I'd imagine that they would be limited to harmonic frequencies only, which will quite minimal, is that right? Any Comments?

Click to expand...

Yes the interference would be either 50 or 60Hz depending on where in the world you live. Any harmonics would be very small and would be dominated by the 50/60Hz fundamental.