Original poster: "David Thomson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dave-at-volantis-dot-org> > What current on the side being fed? It has the full 20 amps to draw from, limited only by the inductance in the ballast. > What voltage across the low voltage (driven) side of the potential transformer? The low voltage side is rated for 120 volts. Dave