Ptss,
I assume that was done before the three new separately derived grounded AC power systems were put into service.
*Check unloaded voltage.
*Check Hot to ground to verify the neutral is grounded.
*Check for AC polarity at load receptacles.
*Connect load/s and check voltage again.
The test I suggested, in my post of 06-14-13, is to find if the three xfmrs outputs are in phase or out of phase with one another.
The same test used to make sure multiple dedicated branch circuits are fed from the same Line, leg, from the electrical panel.
An accepted norm where audio equipment is connected together by ICs.
.
.
Split Single Phase electrical service is most commonly found in residences and smaller commercial buildings,
and is commonly used to feed AV equipment. One key advantage that single phase has over three phase
is that while harmonic currents are still present, it is not possible for the “triplen” components to add in the
neutral. In addition, use of split single phase can result in at least a 6dB reduction in noise floor as compared
to three phase if the capacitances of the connected equipment are relatively well balanced. However, any
leakage currents on the safety ground wires of split single phase load circuits fed by different phase legs will
add together due to the 240V potential difference.
http://www.exactpower.com/elite/assets/pdfs/theTRUTH.pdf
.
Jim
