I have a three phase power filter supplying three different loads, one phase per load, with the return running back through the neutral of the filter. At 15 amps per phase (not always balanced), how do I calculate current through the neutral to know if my filter is heavy enough?
V = 115
I = 15amps (assumed)
Load = computer power supplies

Thanks in advance.

 

To calculate current in the neutral, one must first know the imbalance.

Here is one good way to calculate approximate current in the neutral: http://www.electrician2.com/electa1/electa3htm.htm