To directly answer your question with specificity would require knowing the type of setup you have. Newer coaches and some older ones have combination "inverter" and "converter" units. The inverter provides 120 VAC to certain circuits on the coach from the 12VDC batteries if no other source of AC is available. A converter charges the coach house batteries when connected to external or generator AC power. Some coaches were equipped with standalone inverter units. Most of these were low powered and only powered one circuit such as a TV. Usually they have internal transfer switches that automatically switch to generator or external power if present. Finally there are very small inverters that don't switch between power sources but those are very uncommon as OEM equipment.