I wanted to add the formula on how to calculate the currents flowing in an unbalanced parralled Genst last night, but my sausage fingers were to big for my Android Tablet with it's touchscreen.
So, I am going to post it now from my PC. I like when guys like 3DAngus ask questions.
The internal Resistance of the Generator Coil is 0.1 Ohm for both Units 002A and 003A
I would like to give you the formula based on 3DAngus question about the 120Volt to 100Volt imbalance:
First we subtract the lower Voltage form the Higher Voltage:
120VAC - 100VAC = 20 VAC Differential Voltage
Secondly, now we can calculate the current flow with Ohms Law:
I = U/R where U=20VAC and R=0.1Ohm Internal Resistance
I = 20/0.1 = 200 Amps
This will trip the breaker definetly on the Higher Voltage Generator almost instantaneously - meaning no damage to either Genset
another example:
120VAC - 116VAC = 4VAC
I = 4V/0.1Ohm = 40 Amps
This example will not trip the Circuit Breaker, depending whether or not there is an additional load attached to the paralleled Gensets. Assuming a no external load condition, this paralleled Genset Pair will get damaged within less then 20 minutes of operation due to overheat of the coil.
Again, a small Voltage difference between say 1Volt to 5 Volt will most likely not trip any Circuit Breaker since the Amp Values are to small, but will cause the Coil on the Genset with the lower Voltage to burn out over time.