nanog mailing list archives
Re: Want to move to all 208V for server racks
From: Gary Buhrmaster <gary.buhrmaster () gmail com>
Date: Fri, 3 Dec 2010 17:09:04 +0000
btw, one thing I do not recall seeing on this thread is that 208v avoids one of the common problems with 120v, which is the third harmonic issue. With the cheaper switching power supplies, one will often see significant 3rd harmonics in the waveforms(*). The 3rd harmonic, across a 3 phase circuit, are additive on the neutral. In worst case, your (common) neutral current may exceed the line currents. Proper engineering for significant 120v distribution in new DC construction often requires double sized neutrals to mitigate against this. Using 208v mitigates this particular issue. Gary (*) There are also other harmonics, but for this discussion, 3rd is what matters.
Current thread:
- Re: Want to move to all 208V for server racks, (continued)
- Re: Want to move to all 208V for server racks Lamar Owen (Dec 02)
- Re: Want to move to all 208V for server racks Jeremy Bresley (Dec 02)
- RE: Want to move to all 208V for server racks Alex Rubenstein (Dec 02)
- Re: Want to move to all 208V for server racks Chuck Anderson (Dec 02)
- Re: Want to move to all 208V for server racks Gary Buhrmaster (Dec 03)
- RE: Want to move to all 208V for server racks Alex Rubenstein (Dec 03)
- Re: Want to move to all 208V for server racks Lamar Owen (Dec 04)
- Re: Want to move to all 208V for server racks Chuck Anderson (Dec 02)
- Re: Want to move to all 208V for server racks Kevin Stange (Dec 02)
- Re: Want to move to all 208V for server racks Christopher Phillips (Dec 02)
- Re: Want to move to all 208V for server racks William Pitcock (Dec 02)
- Re: Want to move to all 208V for server racks Gary Buhrmaster (Dec 03)
- RE: Want to move to all 208V for server racks Alex Rubenstein (Dec 03)
- RE: Want to move to all 208V for server racks David Hubbard (Dec 02)
- Re: Want to move to all 208V for server racks Jay Nakamura (Dec 02)
- Re: Want to move to all 208V for server racks Mark Kent (Dec 02)
- Re: Want to move to all 208V for server racks Ingo Flaschberger (Dec 02)
- Re: Want to move to all 208V for server racks Seth Mattinen (Dec 02)
- RE: Want to move to all 208V for server racks Alex Rubenstein (Dec 02)
- Re: Want to move to all 208V for server racks Robert Bonomi (Dec 04)