Sine Wave Inverter Anomaly
After following this recent discussion about how to best utilize a sine wave inverter for RV use I decided to go ahead and buy the 1000 watt model mentioned in this discussion since it was on sale for...
Forum Discussion
brulaz wrote:
SoundGuy,
just to clarify (and forgetting your circuit tester)
what voltages do you read between Hot and Neutral, Hot and Ground,
A) at the Inverter, trailer unplugged
B) in a trailer socket plugged into the inverter
Done ... with some interesting results! Since I have my Surge Guard "permanently" installed I decided to leave it in the circuit as that's how I plan to normally use the trailer, whether powered by shore power, my genset, or from the inverter. I could repeat this test some time later with the SG removed but my bet is the results won't be any different. Measurements were taken with a $20 DVM from Crappy Tire so some variation is to be expected since this isn't a Fluke. Inverter was powered by my aging 7 yr old G27 Interstate battery which is "fully" charged. These tests were taken with the inverter output un-bonded but because I was seeing some unusual voltages where they wouldn't normally be when feeding the trailer from shore power I repeated each measurement, bonding the inverter's output by plugging in my genset air intake fan which is wired with a bonded plug. As a result of the fan load those voltage measurements are somewhat lower but they're nonetheless consistent and it was quicker than wiring up a bonded plug. Bonded results are in { } brackets.
Inverter Output Alone
Hot > Neutral 122 vac {117.5 vac}
Hot > Ground 00.3 vac {117.5 vac}
Neutral > Ground 00.3 vac {00.0 vac}
Main Service Cable Plugged Into Inverter, Surge Guard ON, Converter Breakers OFF, Measured Outside Trailer Where Main Service Cable Plugs Into Inverter
Hot > Neutral 120.2 vac {117.1 vac}
Hot > Ground 121.7 vac {117.1 vac}
Neutral > Ground 32.2 vac {00.0 vac}
Main Service Cable Plugged Into Inverter, Surge Guard ON, Converter Breakers ON, Measured Outside Trailer
Hot > Neutral 120.2 vac {117.1 vac}
Hot > Ground 125.0 vac {117.1 vac}
Neutral > Ground 55.5 vac {00.0 vac}
Main Service Cable Plugged Into Inverter, Surge Guard ON, Converter Breakers ON, Measured Inside Trailer From a Receptacle
Hot > Neutral 120.2 vac {117.5 vac}
Hot > Ground 126.2 vac {117.5 vac}
Neutral > Ground 55.6 vac {00.0 vac}
Whether it's "right" or "wrong", bonding the inverter's output clearly forces it to emulate shore power and eliminates odd voltages where one wouldn't expect to see them. Unless I can be convinced otherwise I think I'm going to bond the inverter's output, just as I have with my genset.
