For a European-style city power supply (240 V AC 50 Hz) attempting to accommodate appliances from another country (USA, 110 V AC 60 Hz), how should a "Nippon" ungrounded transformer be wired up?
The supply voltage for the neighborhood is 240 V AC. The ungrounded 1500 W Nippon transformer steps that down to 110V but leaves the frequency unchanged. Most 110V appliances (heaters, etc) plugged into the 110V side work fine. However, the voltage on each leg of the 110 side ("hot" and "return") are both 55V AC relative to Earth ground. And when I try to connect "active" power regulating loads to the 110V outlet, my the GFIC breaker on my 220V power source eventually trips, whether I've grounded the power supply and/or transformer case to earth ground or not. The troublesome appliance is a 110VAC to 12V DC power supply, battery charger and solar charger system. A lower power transformer from Australia (500 W) does not cause this problem.
Any ideas on what I'm doing wrong with the wiring of the new transformer?