I have an ST5 generator, it is wired on 220V, it came without the configuration jumpers, selection of frequency and voltage, so it is fixed at 220V 60hz at 1800 rpm.
When I measured one of its output referenced to its case, its output is 110V,the other output is 110V referenced to the case also. Is this normal? Is it important to attached the case to ground, as in the ground connected to the soil?