Oh, but it does help! Peaks in the real world are not square waves, and the phase angles of 3-phase power does help us. Here is an o-scope metering of 3 typical PC supplies, from the high end to the cheapest.
![[Linked Image from pcpowerandcooling.com]](http://www.pcpowerandcooling.com/products/reviews/pcp_silencer/Oscope_web.jpg)
On the cheapest of the cheap (which we don't see in places that are going to be using 3-phase power), you'll see a peaked sinusoudal wave at about 180Hz on the neutral with short pauses of 0 current between. As PFC is added to the PSUs, the spikes widen, and current flowing in opposide direction from the different phases begin to cancel. A large harmonic is left, but it's not as bad as our super-cheap PSU. On the best PSUs, the current on the neutral cancels almost completely. In all cases you'll see harmonics to some extent, though.
[This message has been edited by SteveFehr (edited 08-01-2006).]
