Sine Wave Inverter Anomaly

vermilye wrote:
While I obviously can't prove it from here, I suspect the "stray" voltages you are seeing are inductive leakage. The high impedance of your volt meter don't load the connection enough to eliminate them.

You could prove it by switching the meter to amps & see if there is any current between the neutral & ground. A safer (and possibly less exciting) test would be to get a pigtail lamp socket with a 15 watt incandescent lamp & use that to make the connection. I would be very surprised if it lights. If it is inductive coupling, the available current will be so low that it is unlikely to cause any problems with equipment.

As to the "noise" created by the pure sine wave inverter, the only way to really know if it is the waveform is to throw a scope on it. Without doing that I can only speculate, but you might try loading the inverter with a load around 10% - 25% of its capacity. Many devices (including non inverter generators) produce lousy waveforms unless loaded.

Some interesting examples of device waveforms is linked here.

I have used a scope many times during my career but now that I'm retired I don't really have ready access to one any longer so I suspect I'll probably just have to assume this inverter's output waveform, while sine wave, may just be a bit ragged nonetheless. Good idea to measure current between neutral and ground with a DVM ... that I can do. Thanks for your ideas! :B