[Amps] Benefits of 3-phase power?

[ka1xo at juno.com]

Dear Gene,
Having been fortunate to have 3-phase power available in the lab where we Type-Accepted DC Powerplants for cellular transmit sites I took advantage of the situation and hooked up a strip chart recorder to the three hot legs of the 5-wire service and to the three wire service of the split single phase mains supply to be able to tell the customer about sags and surges. While both services suffered equal amounts of transient pulses, measurable from 3 nS up to 1mS, and in equal amplitude, the three-phase service suffered less than one-third the amount of events from 1mS to 1S. The customer decided to bring in 3-phase power to as many sites as were possible, the big hurdle being the nearby availability of three-phase lines in the street.

The everyday advantage to using 3-phase mains is smaller wire diameter and lighter motor frames for the same HP. 

But who has 3-phase going to their house?

Hal
KA1XO