So here's the situation. I have a camper. That camper has a 55 amp converter that supplies 12 volt power from 120 volts shore power and charges my 400 amp hour lithium iron phosphate battery Bank. I recently got a larger generator to to replace the undersized generator I had for boondocking. When connected to this 4,500 watt generator having the converter on causes my air conditioner compressor to make a ringing hissing sort of sound. This does not happen when connected to regular shore power or strangely enough on my old 2500 w generator from the same brand.
I contacted the generator company and they sent me a new inverter board for the generator. This did not fix the problem.
It is not voltage sag because the smaller generator sags more under this load and doesn't have the problem. I can also run the microwave at the same time as the air conditioner on the 4500 watt generator and it does not cause the problem even though the microwave is more of a load.
Frequency is right at 60 Hz the entire time other than a very slight fluctuation when load increases or decreases. This is verified with an oscilloscope and a bryman 867 meter.
I tried a different brand of converter and it does the same thing.
Looking at the oscilloscope waveform it is flat topping pretty dramatically when the converter is on but it does that on shore power as well and the noise isn't there.
Getting a different generator might fix the problem but it might not and I'm not really in a position to buy yet another generator.
I'm attaching a link to a video for exactly what's happening. This is me switching the 55 amp converter on and off.
Questions are
1) what could this be?
2) other than replacing the generator what can I try to do about it?
3) is whatever this sound is actually causing harm and can I just ignore it?
I've asked in camper groups electronics groups on Facebook air conditioning groups and have not gotten any information beyond what I already know.
Help is greatly appreciated!
https://drive.google.com/file/d/1fsoHn04KBU5iVOQ0wzKR1nrUcSogAe9Q/view?usp=drivesdk