Quote:
Originally Posted by Bazz4CQJ
I have a 2kW constant voltage transformer which works by some ferromagnetic effect which I don't present recall in detail, but it produces a distinctly non-sinusoidal waveform. Now, a constant voltage suppy for my 163 would be nice, but when I tried it on the 163, that particular unit had quite a significant effect results obtained; unuseable!
B
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Somewhere in their manuals AVO mentions that you shouldn't use constant voltage transformers due to the effect they have on the measurements, but unfortunately they don't write it in all of their manuals.
The VCM163 is sensitive to outside noise from switching power supplies, constant voltage transformer which produces overtones due to the non sinusoidal waveform and other equipment that distorts the waveform like solar panel inverters.
I've used constant voltage transformers that works like a variac but with a motor that controls the shaft of the variac, where the motor is controlled from a voltage sensing circuit. They work just fine but they didn't have much of an effect since the voltage is quite good where I live, but for people living in areas with more fluctuations they might be good.
I sometimes check my measurements on the VCM163 by using a small isolating transformer as that filters out some of the noise on the power lines and I always use it if I run the VCM163 with open panels for some tests. Especially now that I am developing the Solid State Calibration Vacuum Tube - I just have to remember to remove it for some tests as the design might be sensitive to the noise too and that has to be taken into account!
/Martin