3000W Chinese Gensets Info.

professor95 wrote:
Bob,

I am having a little trouble interpreting the chart, particularly the Harm# source. I am OK on the graph. Remember, I went to school in the late 60's when 5U4 vacuum tube rectifiers were still used with swinging chokes and transformers :)

Can you please give a little more explanation for interpretation?

Ok, the "harm#" is the harmonic number. Since we are 60 Hz, the 2nd harmonic is 120 Hz, 3rd is 180 Hz, etc.

The "harms(avg)" and "harms(max)" are the currents of each harmonic, in amps.

The limits are from the EN61000-3-2:2006 standard for power harmonics emissions from products.

Very few products for the US market are tested for power harmonics. Most, if not all, products for the European market must meet this standard. Why, I don't know for sure, this topic is a little beyond my realm of knowledge. The reason I've been told why Europe requires it is because of the way power is distributed being slightly different than in the US. In Europe, residential power is distributed on a 3 phase wye system, with each house being on one phase. It is 230V Line-Neutral, or approx 400v L-L. The harmonics from multiple products on each phase can combine in the neutral conductor and cause it to overheat. In the US, the residential power is single phase from a transformer, with the neutral derived from a center tap of the transformer output. Anyway, that is what I have been told, but I admit I don't fully understand it. :h

Anyway, here is some more interesting info from the test that I should have included.

Highest parameter values during test:
V_RMS (Volts): 120.02 Frequency(Hz): 60.00
I_Peak (Amps): 22.440 I_RMS (Amps): 6.333
I_Fund (Amps): 3.362 Crest Factor: 3.550
Power (Watts): 412 Power Factor: 0.544


Notice it is only 412 watts, but with a peak current of 22 amps. :E